Transcript for:
Networking Full Course Notes

networking is the practice of connecting two or more computers or devices to enable communication and information sharing this connection can be established through various means such as wired or wireless connections it can serve multiple purpose including sharing resources communicating with other users accessing the internet and many more devices are connected using network protocols such as ethernet and Wi-Fi and are assigned using IP addresses that allow them to communicate with each other networking is an essential component of modern Computing and is used in various settings from small businesses to large corporations and from home networks to Global networks networking is a rapidly growing field with many career opportunities available as technology advances the need for skill networking professionals is increasing some of the most popular networking career opportunities include network engineer network administrator Network security specialist wireless network engineer Cloud network engineer and many more according to Blaster a network engineer's average salary in the United States is around 81 000 in India it is 5 lakhs per annum the help of our Celtic cyber security boot camp you can launch your career as a cyber security specialist and acquire the knowledge and expertise businesses need to safeguard sensitive data and vital systems from cyber attacks with that in mind Hey guys welcome to the networking full course video by simply learn this video will begin with the basics of networking for beginners followed by ethernet we will learn about types of networks next we will move on to topics like Network topology IP address osm model and TCP IP protocol finally we will cover the topics like network security farewall network routing using digital's algorithm and error deduction then we will dive into little Advanced topics like stop and weight protocol sliding window protocol go back in arq protocol and selective repeat erq and cover Dynamic cost configuration protocol we will conclude this networking full course by discussing the essential interview question and answers of networking to help every individual crack an interview so let's get started with the two major types of network that should be considered basic knowledge for someone starting out with networking lands and rents the first variety of networks is a local area network also known as Lang it comprises of cables gateways switches routers and additional parts that allow these devices to connect to private servers cloud services and other lands via larger Networks the growth of virtualization has also sped up the creation of virtual lands which let Network managers divide and logically organize Network nodes without having to make significant modifications to the infrastructure the computers in each department could be conceptually linked to the same switch in an office with many departments be it accountancy it support and administration still they might be segregated to operate separately the benefits of a lan are similar to those of any collection of connected devices they may access anywhere control one another exchange files print to Shared printers and utilize a single internal connection to better understand this logic let us take a sample structure you can see the various components of a local network connection in this picture and now we can see three different devices a system a laptop and a printer so you have these few devices that need to be connected to a single local Ada Network now to identify these devices inside the network we need to assign an identifier to each device so this is where an IP address can help an IP address is a language string of digits allocated to any device connected to a network that utilizes Internet Protocol as the communication medium is the digital equivalent of your house or workplaces mailing address the addresses are divided into four sections separated by drops each traditional tree strain numeral portion represents an 8-bit binary integer which can range from 0 to 255. these four integers are expressed in normal decimal notation and then separated by Docs however computers work with binary numbers meaning zeros and ones and each number in an ipv4 address represents an 8-bit binary integer which is why none of them can be more than 255. the distribution of this IP addresses is not just limited to land every device which is a part of the network will have its own IP address as assigned by the network administrator as seen in the picture we can now identify each device individually by the designated IP addresses now the primary purpose of a network being the ability of multiple devices to communicate and exchange information with each other this IP addresses serve only half the purpose since allotment and identification of these addresses need to be managed automatically and On Demand if the laptop shown on the left of the screen wants to use the printer in the network it needs to know which particular device or more precisely which particular IP address to communicate this is where a switch comes into play it takes a role of the delegation and commands in a particular Network let's learn more about switches in detail a network switch joints devices in a network such as computers printers wireless access funds and allows them to communicate with each other by exchanging data packets they can do both physical Hardware devices that handle real networks or software-based virtual devices the vast majority of network equipment in modern data networks are switches will index the PCS access points automated equipment and some iot devices via wired connections such as card entry systems the LinkedIn computers and data centers that run virtual machines or VMS as well as the actual server and most of the storage equipment based on the type of switches employed they can either differentiate between network devices using either their IP addresses or Mac addresses which are separate types of addresses allotted to each Hardware device irrespective of the network it is connected to now that you understand the major parts of a local area network a major query that may come to your mind is how can these local networks can communicate with other networks a rocker is employed at the Forefront of every network setup to facilitate communication between foreign Networks this router can then be used to connect to the Internet so we can communicate with the loved ones from the comfort of our own homes so let's learn a little more about routers the router is a physical or virtualized Internet working equipment that receives analyzes and transmits data packets across computer networks the router checks and data packets destination IP address and utilizes headers and forwarding tables to determine the best path to transform the packet consider the router to be an air traffic controller and data package should be airplanes flying to various airports or networks and space each package like each chat has a unique destination and must be steered to its destination as effectively as possible a router helps direct these data packets to the intended IP addresses in the same manner that the air traffic controller ensures that flights arrive at their destination without getting loss while experiencing severe disruptions router employs an internal routing table which is a collection of Pathways to multiple Network destinations to properly direct packets it scans the header of a packet to establish its destination then consults a routing table to find the most efficient way to their destination the packet is subsequently sent to the next Network along the Route a router also has an IP address which is often called as the network Gateway a crucial part of the networking setup is determining whether a particular piece of Hardware is a part of a local network or a foreign device as you already know specific IP addresses exist for each device in a network be it a local or wide area network all these IP addresses must belong to a particular range of addresses which are often known as the subnet or sub Network and it's helped return on the overall range of a local area network for example the IP addresses that can be seen on the screen right now belong to a subnet that is 255.255.0.0 the first of flags did not fix values that must be present in every single IP address of every single device in this particular Network in our case the 192.168 is the consistent factor in every single IP address shown on the screen this implies that if the devices can connect to a piece of equipment with an IP address and it starts from 192.168 that device will most likely be in the same local area network the last two places are the three ranges in this example which means they can be any number less than 255 further helping the router and switch differentiate between multiple IP addresses in a network with that being said we can now take a look at how wide area networks work a wide area network or a van is in its most basic form a collection of local area networks or any other networks that interact with one another why Data Network is essentially a network of networks with internet serving as the world's biggest one however when a router communicates with devices outside a local network it tends to mask the internally allocated IP addresses and uses a single public IP address for all the devices this process is called Network address translation or Nat IP allocation a network address translation is a method of translating one IP address to another while these packets are in transit through a router this improves security and reduces the number of IP addresses required by a company answer how to receive some particular information that must be transmitted to a local device in the network it checks the internal routing tables to determine the correct internal IP address and the current destination to send the external leadership data too but let's say a device on the external network or a wide area network wants to communicate directly with the device from the local network this cannot be allowed since this can be a very big security risk for devices in a secure environment all of this M3 and exit rule creation and handling can be taken care of by a firewall a firewall is a type of network security device that analyzes the incoming and outgoing networking traffic and allows organized data packets depending on a set of security rules its objective is to provide a barrier between your local network and external traffic such as the internet the most common sort of firewall which are packed at filtering firewalls check packets and prevent them from getting through if they do not maintain established security rules this sort of firewall examines the package destination and Source IP addresses if the packet fits an allowed rule on the firewall they are permitted to access the network but let's say we as users want to allow external requests to reach individual computers or devices on our local network there are two ways to facilitate this Behavior the first way to go through this step is by using a DMZ which stands for a demilitarized zone instead of communicating directly with the local network device the external data is sent to the router instead the router will have created a DMZ sub network with only those devices added to it that require other external information to reach them on altered once the data is received by the router it passes it on to the dng subnet and subsequently to all the devices which are a part of that summary however since external data can reach devices in a network without any firewall checks if they are part of the DMZ subnet the security risk associated with this method are very large compared to the second variant which is port forward ing is a method of granting external devices access to computers on private networks it accomplishes this by translating an external IP address and port to an internal IP address and port all the devices talk to each other and the network Gateway using the IP addresses and specific ports for example the TCP IP protocol basic internet usage uses Port 80 on every Network similarly we can create additional file or rules to open up certain ports for external devices to communicate with if the designated ports are open during communication the firewall will allow the external network device or server to communicate directly with the local network device without any hindrance so it's always really need to know for now about the basics of networking hope you learned something new today what is ethernet ethernet is a form of communication Network that uses a wired medium to connect devices for data Exchange in the network for example LAN also known as local area network also van known as wide area network ethernet also applies different protocol on the data to be transmitted over the communication Channel efficiently and smoothly moving on let's look into why to use ethernet as we now know the ethernet is a mode of connection for multiple devices to share and exchange data but using this way of transmission also has its benefit for example the ethernet Network provides us with a high speed connection for sharing data ethernet also provides the user data with a secure channel for transmission the data that is transmitted over the ethernet channel is reliable and has rarely faced in issues at the sender site let's move on to the next heading now we will look into different types of ethernet in general the ethernet is divided into three different types first is the fast ethernet this type of ethernet operates on a twisted pair cable with the data transmission speed of up to 100 Mbps fast ethernet connections are used for personal connections or use in companies that require low internet connection moving on we have gigabit Ethernet this Linux is used for high-speed internet connection with the speed ranging from 1000 Mbps to 1 gbps it is an upgraded form of fast ethernet and the last type is switch ethernet this ethernet type installs network devices such as switches or hubs so as to improve the network transmission the transmission range for switched ethernet connection is around 1000 Mbps to 10 gbps now let's look into the working of ethernet ethernet Services specifically work in the first layer of the OSI model that is known as the physical layer and the second layer of the OSI model also known as data link lab functioning of the ethernet can be divided into three different parts First Step being acquiring the physical address that is Mac address media Access Control address of the sender and the receiver device then the second step is to check the data security quality of the data and the connection speed of the transmission channel for efficient and smooth transmission of data over the network and the last step is to check Network traffic and detect any error that occurs in the communication Channel to solve these issues if occur csma protocols and other Protocols are used for example the csma protocol is used in case of packet Collision in the network channel now let's look at a simple ethernet model for further clarification of the steps but before we begin with the model the point to be noted is the transmission of data over the ethernet channel is divided into two parts frames and packets where packets represents a unit of data in the network whereas frame refers to a collection of data packets being transmitted over the channel and the application of ethernet Services which includes security traffic check and protocols being applied on the data and that is when it reaches the receiver end moving on let's look into advantages and disadvantages of using ethernet for advantages we have cost of installing ethernet connection is low in comparison to other network channels the security of the data being transmitted over the ethernet channel is maintained as for disadvantages we have it is suitable only for establishing short distance communication Network due to high requirement of Hardware resources whereas ethernet is also not suitable for sharing real-time data and information let's look into some more advantages and disadvantages ethernet is suitable for maintaining the data quality of the information being transmitted it also provides high-speed data transmission option for the network for disadvantages we have the network traffic issue is a drawback of installing ethernet cables troubleshooting faults and issues in the internet cable is also a Troublesome work now let's move on to the last heading for this topic that is ethernet versus internet the first difference is connection medium for ethernet connection physical cables are required that means it uses wide medium for connection whereas in case of Internet it uses Wireless mediums such as satellites has a connection medium moving on the next difference is Network model the ethernet is available only for a low distance connection for example LAN whereas internet is available for all the network connection distances beat Lan man or van let's move on to the next difference that is Network control for ethernet the complexity of the connection medium is low due to the less distance it uses and also provides much efficient transmission of data over the communication Channel whereas for internet is a large collection of networks and hence require large group of administrator for control the last difference between ethernet and internet is network security and reliability ethernet connection is a secure network from external interference and provides data security whereas in case of Internet it is an open type of connection so it is more prone to hacking attempts and less secure network with the first setting that is what is a computer network a computer network refers to a group of networking devices for example computer system switch router or hubs connected to each other through our central unit to share Hardware resources and Information Services the more to connect different devices in a computer network can be based on wired or Wireless medium which depends upon the requirement of the user and the availability of network channels now let's move forward with the next setting that is different types of computer networks available in a network channel thank you there are different types of computer networks available to choose from which also depends upon the need of the user or the network channel on this basis we can differentiate into four different types where the first is personal area network that is pan Which as the name suggests is used in personal area to connect devices like mobile phones personal computers etc the next type of network is local area network also known as LAN this area network is used to connect multiple devices across different buildings on multiple devices in a single building and the next computer network is metropolitan area network also known as man which connects multiple land networks within it as for the last Network we have wide area network also known as van which covers locations that are not easily available through wired medium for example different parts of states are connected to each other using wide area network in this session we will look into local area network metropolitan area network and wide area network let's move forward with the first that is local area network the local area network or Lan is used to connect devices that are available in a limited range or small geographical location as it does not cover large locations because of Hardware limitation the devices that are connected in this computer Channel use multiple protocols for proper and efficient exchange of data and internet services the data exchange occurs from a server device that acts as a central unit and is passed on to the devices that are connected in the network channel let's take a look at some of the features of local area network the data transmitted in the network that is Land network is relatively higher in comparison to other network types man and man because it covers a small geographical distance so the speed of data transmission is very high land uses private Network addresses for network connectivity as the exchange of data and services takes place in a closely lit Channel which decreases the error occurring rate and also provides much better security let's take a look at some of the advantages and disadvantages of applying Lan Network for advantages we have it has a single control unit which is used to store data and information and can be used anytime transferring of data information becomes much easier and much faster in line Networks as for disadvantages we have data security is compromised if the Lan admin decides to steal data and information as for the other disadvantages it requires constant Administration for continuing data services and distributing Hardware resources in Align Network with this we have completed the Lan Network part let's move on to the next that is man network the metropolitan area network or man is a network type that encompasses network connection of an entire city or connection of a small area in a country the area covered is less in comparison to van and faces moderate Network traffic due to the large location it covers the exchange of data occurs from one line Network to the other Lan Network and this case is looped let's take a look at some of the features for metropolitan area network the metropolitan area network covers a large geographical area and is also used as an internet service provider by many of the local services because it provides High data transmission rate it also applies many network devices for smooth data services and is connected through telephone lines using wired medium to provide High internet services let's move on to the advantages and disadvantages of using man it applies fiber optic cable for high transmission and much better security in comparison to Lan Network it also uses full duplex method for data transmission that is data exchange occurs simultaneously as for disadvantages we have it needs a good quality Hardware resources and the cost of installation is very high it also needs an experienced technician to maintain and provide much efficient data services in case of man network now let's move on to the next setting that is Van Network the wide area network of van is designed to connect devices over large distances like a Global Network that is the internet because the wide area network covers a very large geographical area for example connection between different states or even between countries it uses Wireless Medium as a connection mode for example Network tasks and satellites it also can be termed as the connection of multiple lands or multiple mans let's take a look at some of the features of wide area network wide area network uses satellite Medium as we already saw the satellite medium is used to connect multiple Network tasks which in turns provide high-speed data connection for the devices in a network channel whereas the data transmission rate of a wide area network is in comparison to Lan and man very low because it uses Wireless medium in most of the cases so the speed of data transmission is low and it also covers a larger distance so it often faces data errors and loss of information now let's take a look at the advantages and disadvantages outline one network when Network uses multiple Network tasks to connect numerous devices to be interconnected with the internet it also covers a very large area to establish multiple connection between different parts of a country and also connect different countries as well let's take a look at the disadvantages of applying van Network the chances of an error occurring in a van network is very high due to the availability of different types of network channels network devices and different modes of connection medium the initial cost of setting up a van network is very high as it needs very experienced technician to work on and requires Hardware resources example satellites Network tasks which are very costly to set up let's begin with the first heading what is Network topology it is referred to as an arrangement a multiple system and network devices interconnected to each other through a physical medium or logical channels the term Network topology is combination of two individual Network concept first is the network part which represents the devices or systems that are also known as nodes which is connected and how to change the data within the network then the other part is topology which represents the connection medium between different network devices and governs the data flow between them moving on let's talk about why do we apply the concept of network topology for the first point it allows the users to understand the overall model of the network along with the number of devices installed and their positions in the network which provide ease of installation of security measures and network and helps in case of troubleshooting cases then for the next reason applying Network topology helps the user to understand the communication relationship among the different devices and through a connection medium this in turn helps the network professionals to set up an optimal Network unit for the user next in the list we have different types of topologies used in networking first is the bus topology then we have ring topology Then star topology then tree topology and in the end mesh topology but to understand the concept of topology let's start by point to point topology this is simpler form of topology connection which consists of two nodes connected through a connection medium like a network cable the nodes at the two ends of the cable shares data information between them where the data sharing part represents the network and the cable connection is the topology part with this we have understanding of network topology then let's begin with complex types of tech connections first is the bus topology in this topology the connection channel is a single cable known as the network backbone through which all the other nodes are connected to in this network setting the data packets sent by the nodes are provided with the receiver address to avoid transmission errors the data in this topology can travel from any endpoint where they are termed as terminate points advantages of bus topology it is easy to set up due to that simple configuration settings this setting is also cost effective as it requires only a network cable for the connection in the case of krishnor the whole network remains unaffected as it does not have any direct connection to the other node let's take a look at disadvantages of bus topology in case of troubleshooting we require the use of special equipment to detect The Fault in the network in the case of multiple data transmission the packet Collision is the frequent occurrence damaging the transmitted message data due to the unavailability of network devices such as switches repeaters Etc the loss of data over long distances communication is quite High then ring topology as the name suggests the node in the network are connected in a circular pattern similar to a ring the data transmitter in this connection is always in the clockwise Direction the topology does not have any termination point due to its ring structure the method of data transmission is used is known as token passing which involves sending a token along with a data packet to which each of the node matches to identify the destination node using the destination address in the token next advantages of ring topology the crash node can be easily removed from the network the configuration settings are not complex for certain and materials are easily accessible the cost of installation is low as no extra Network device are required to the connection moving on we have disadvantages of ring topology in the case of a node crash the whole system is affected and is known accessible due to the direct connection of each node the transfer of data is slow due to the Token processing method in the network difficulty in The troubleshotting Fault in the connection leads to the crash of the whole network now let's talk about start apology in this topology the networks are connected to each other through the central Hub which can be a computer or a server the central unit in the connection is also known as the server and the nodes are known as the clients any connection between the node has to be through the server and is one of the most popular topology connection next advantages of start apology in case of a node crash the network as a whole remains unaffected as each node is connected to the server of a connection the hardware requirements are easily available and of low cost troubleshooting is easy through the use of central Hub to identify the faulty node disadvantages in case of a server failure the whole network is shut down as all nodes are interconnected through the server the connection configuration is complex due to the pattern of the typology next up free topology this topology is a combination of tar and bus topology the node Connection in the topology follows hierarchical pattern with the topmost node as a root and the branching node as the child node the sharing of data is from the root node to the child node pattern next up advantages of tree installation of a new network group is easy due to the root child configuration of the network in case of a node fault or trash the whole network is not affected by the error this makes it easier to troubleshoot the issue next up disadvantages in case of a server crash in any of the star connection group the whole network is affected due to the complex setting of The topology installing security points is difficult in the network configuring and troubleshooting internal issues is quite complex due to this topology next up match topology as the name suggests this topology is a connection of interconnected system connected to each other in no particular order no installation of network devices such as switch or hubs this topology pattern can be divided into two forms first is full match topology in this connection all the nodes are connected to each other in the network then we have partial mesh topology where all of the nodes are connected to each other available in the network let's talk about the advantages of mesh topology in case of node damage the whole network does not suffer from the fault due to the interconnected patterns of the connection the transmission of data is very high in the network next up disadvantages the cost of installation is high due to the requirement of multiple cables and nodes for the network to function efficiently the management of the network becomes complex due to the large number of interconnections in the network due to the absence of repeater or a switch the data signal loss during the transmission is very high now let's take a look at how to choose best topology for a network configuration first of course the installation cost is one of the biggest factor that affects the type of topology configuration we choose from our Network as the cost of installing cables routers such as and other network connections is slow then we have easy installation installing the hardware devices efficiently and precisely is also one of the factors that affect our choice of network topology moving on we have flexibility the ability of the topology to include new network nodes after installation and ease of troubleshooting refers to the flexibility of topology in the hand we have reliable security it is important that the Tuple installed allows us to introduce proper security point in the network and leading the fewer crash cases by referring the above factors we can decide the best topology of for our Network assuming that a person had to send a letter to a relative's house but he wasn't sure which house though so how can this problem exactly be solved well this problem can be solved if we take a look at the house number mentioned on the meal let's take a look at the house number mentioned on the meal on the meal it seems like the house number is 2 that means the meal would go to house number two similarly we also have an identification method on the internet that is known as IP address which is used to identify different mails and the owner of that email address let's now take a look at the agenda for today's video firstly we will know what is an IP address then we'll see what functions does IP address have moving on with knowing different versions of IP addresses and lastly different types of IP address firstly we'll understand what exactly is an IP address an IP address or Internet Protocol address for an example is a unique numerical identifier assigned to every Network device when it connects to the internet this address is assigned by the internet service provider which acts as a way for the system to access the internet applications and the unique identity for the device moving forward we will understand what exactly are IP functions to begin with IV functions can be divided into two types for the first function we have the internet service provider assigns an IP address to the network device the first function of the address is to provide an identity to the host on the internet whereas the second identity is used as a location address for the host on the internet let's now take a look at different versions of IP address IP addresses can be divided into two types where the first type is known as ipv4 address whereas the other address is known as IPv6 let's take a look at both of them in detail for first one we have ipb4 address this is the original version of an IP address developed on 32-bit binary format which contains 2 to the power 32 address the address range from 0 to 255 in terms of zeros and ones with four octets each of them separated by a period the network device uses binary format whereas the numerical format is used for the host reference the first part denotes the network part in an IP address and the second part is for the host part now let's move on to the IPv6 address type with the rise in technology the ipv4 could not complete the requirements so the need for ipv4 arrows based on 128 bit address size which is sufficient for a long time which is approximately 320 undecilion this type of IPv6 address is designed for four hexadecimal digits and 8 sets with each block containing 16 bits separated by a colon now let's take a look at the IP classes IP classes are designed for the purpose of EC assignment of addresses to the network divided on the basis of class size we have five classes depending upon the requirement of the network plus a were designed to accommodate networks with a large number of network hosts with first bit in the octet is always zero with the large number ranging from 0 to 127 then we have class B Class B fulfilled the requirements for medium size Network host where the first two bits for the network ID is 1 and 0. with the range from 128 to 191 then we have class C which can fulfill the requirement for small size Network host where the first rebirth for network ID is one one and zero ranging from 192 to 223 from this we get that class A B and C are used for assigning addresses to the host Network and then we have class D which is used for multicasting which means it is used to send a signal from one host to multiple hosts like cubes and video streaming where the first four bits for network ID is 1 1 and 0. with a range from 124 to 239 and lastly we have class E network ID for this range is reserved for research purpose and not assigned to any network with a range from 240 to 255. Let's see different types of IP addresses on the basis of accessibility we have private IP addresses and public IP addresses for private IP addresses the devices are assigned addresses in a network and each system is provided with a unique IP address which they can communicate through within the same network and cannot access public network and they do provide much more Security in regards to the public IP addresses take a look at the public IP address now for public IP addresses ISP in or Internet service provider assigns it to the router which allows a user to access the internet and also different network application can be accessed with security Less in comparison to private IP addresses let's now see the other two types of IP addresses which are static and dynamic IP addresses authentic IP addresses is assigned manually and is constant to the system whereas dynepic IP address is assigned by the internet service provider for static IP addresses the importance is much more whereas the address is used for business and is not beneficial to have different IP each time in case of dynamic IP address the assigned IP for network devices do not need dedicated IP due to being constant in nature static IP address is preferred to be assigned as official address for a business whereas in case of tiny pick IP address due to assigning different each time when it connects to the internet address provides much better security and often prevents hacking now if you want to take a look at the IP address for a system which is publicly available we can do by the following steps access your internet browser and type IP address and over here we can take a look at the public IP address for the system and if you want to take a look at the system IP address which is dedicated to the device you can do the following steps access command prompt and write the command ipconfig and you can take a look at the system IP address let's take a look at the first heading that is ip4 addresses the first version of an IP address to be developed was based on 32-bit binary format that counts roughly around 2 to the power 32 bits of total IP addresses in ipv4 format video sufficient at the initial phase of network requirement but is somewhat lacking according to the current advancement in the Network Technology the addresses in this IP ranges from 0 to 225 in terms of zeros and months with 4 octets where each of them is separated by a period this is an example for an ipv4 IP address where the first three parts represent the network ID and the last part represents the host ID using the ipv4 address as I reference we can identify ipv4 addresses from IPv6 addresses now let's move on to the next topic that is ipclasses IP classes are designed to allow easy and efficient assignment of IP addresses to a network depending on class size we have five different IP classes in a network that are named as a b c and d for the first part we have class A that accommodates network with a large number of network hosts where the first bit in the octet is always zero with number value ranging from 0 to 127 then we have class B which can fulfill the requirement for a modded number of network hosts the lead bit is 1 and 0. and network ID ranges from 128 to 191. then we have class C which can allocate an IP address for Low number of network host where the first three bits of the network ID is 1 1 and 0. ranging from 192 to 223 so the above three classes that is Class A B and C we can easily identify and assign addresses to a network host moving on behalf class D where it is used for multicasting that means it is used to send multiple signals at the same time from a single host for example using video streaming where the lead bit is 1 1 1 and 0. with network ID ranges from 224 to 239 and then we have class E where the IP bits for this is reserved for research purpose only where the IP addresses ranges from 240 to 255. moving on let's take a look at some of the features for ipv4 version addresses where the first is the memory required for student ipv4 version addresses in a system is very low then we have ipp4 version addresses apply connectionless protocol for sharing data and providing the best effort in delivery moving on we have stacking option for ipv4 addresses that means in ipv4 version it allows to create a multiple network over a single host which allows different hosts to connect to it moving on we have ipv4 version addresses being the earliest IP design are applicable to most of the network devices and system for connecting to the internet so it is supported by many devices then we have IPv6 addresses let's take a look with the increase in the need for an IP address the ipv4 version addresses are somewhat unable to complete the requirements of the network host so the need for ipv4 version Eros which is based on 128-bit address size which is sufficient for a very long time that is approximately 320 under zillion IP addresses in version 6. this type of IPP version is designed of four hexadecimal digit and 8 sets with each block containing 16 bits separated by a colon moving on let's take a look at some of the features for IPv6 version addresses where the first is ipv version 6 addresses provides an integrated security protocol for the network that is Internet Protocol security ipsec then we have it allows its application to extend in various Services according to the need of the network it also allows address configuration pretty stateful that uses DHCP server for network settings and stateless that applies Auto configuration settings IPv6 addresses also allows some methods to convert ipv4 addresses to IPv6 addresses which is according to the requirement of the host or the network moving on let's take a look at the differences between ipv4 version addresses and IPv6 version addresses this heading would allow us to choose a best IP address that we can decide for a network let's take a look at the first difference that is address and performance in accordance to the address size ibv4 version is composed of 32-bit address length and is the fourth version of the Internet Protocol for IPv6 we have the address size is 128 bit long and is the latest version of the Internet Protocol the second difference is on the basis of address field type IPv6 addresses are based on numeric data with four Fields each separated by a period whereas for IPv6 addresses are based on alphanumeric type data with eight Fields each separated by a column the next difference is based on address configuration in ipv4 version addresses a manual setting for the network is required along with the dhcb configuration settings whereas in case of IPv6 version addresses the network setting is based in accordance to the systems requirement and it also supports Auto configuration setting for the system foreign in case of ipv4 the total number of addresses are nearly 4 billion addresses whereas in case of ipe6 version we have 320 undecilion addresses now let's take up a quiz to understand what we did so far and the question is identify the correct form of ipv4 version address in the given options and the options are you can give your answers in the comment section below let's move on to the next difference that is address security and functioning ipv4 version addresses do not provide any security function for the network whereas in case of IV 6 addresses integrated Internet Security protocol at its ipsec it's responsible for the security of the network the next difference is encryption and authentication settings ipv4 version does not provide any encryption or authentication services for the network IPv6 addresses do provide mandatory encryption and authentication services for its addresses moving on behalf address routing and performance ipv4 version follows routing protocol that has rip for network configuration and is preferred over IPv6 version and in case of IPv6 it does not follow any routing protocols and it uses static routes for Network functioning now that we have completed with the differences between IPv6 and ipv4 we can easily identify the IP address we want to choose for our Network for today's topic firstly we will understand what is an osr model then we'll see the structure for the OSI model continuing with knowing the layer structure and information in the OSI model let's start to better understand the OSI model let's take a look at a scenario assuming we have two different systems with different operating system installed in them and there is a communication Channel between them over which the data is shared but sometimes during transmission of data it faces some problems these errors often arise due to the different operating system installed in the system or due to a network problem during a transmission but to overcome such situations The OSI model structure is used using the OSI model structure we can make the transmission of data over the communication Channel error free let's take a look at the definition for the OSI model the osm model stands for Open System interconnection model or a specifically designed set of protocols and standards that governs the modeling and conversion of the data for proper transmission over the network channels the osm model is based on the layer structure where it consists of seven different layers where each layer has different set of protocols that are to be applied on the data during the transmission over the network channel let's take a look at the different layers of the OSI model the osm model consists of seven different layers which perform specific functions and apply different protocols at different layers to maintain the quality and prevent the data from getting corrupted when it is transmitted over the communication Channel let's take a look at each of them the first layer is known as the application layer which is a topmost layer then we have the presentation layer session layer transport layer Network layer data link layer and physical layer which is the last layer of the OSI model the upper four layers in the OSI model represents the host layers that is they interact with the application related issues when the data is transmitted over the communication Channel whereas the lower layers are termed as networkless they specifically deal with the transmission related steps for the data over the network channel let's take a look about some information in regards to the layers now let's take a look at the function and the data format that is handled by each of the layers during the transmission of data the first layer is the application layer which interacts as a Gateway for the host data and network applications and handles the data format then we have the presentation layer which handles the initial step towards the conversation of data for transfer it also handles the data format then we have the session layer session layer establishes a connection between the network devices for the data transfer then we have the transport layer which oversees the data that is transferred without any error and is in the same pattern needed by the destination system the data format handled by this layer is segment format next we have the network layer which determines the part for the data transfer it handles packet related data then we have the data link layer which performs the task of connecting the physical nodes for the transfer of data it handles Frame data and in the end we have the physical layer which is used to transfer the raw bits that is in terms of ones and zeros over the physical mode now that we are clear about different layers that are present in the USM model and some information regarding them let's take a look at each of the layers in detail we'll start with top to bottom that is the application layer will be the layer that we'll be starting with let's take a look the topmost layer in the osm model is the application layer which acts as an interface between the user and the applications that are being accessed which can be Internet Explorer Chrome or any email client it also handles different protocols that are needed for the data transmission over the network channel which can be given as hypertext transfer protocol the HTTP protocol and the SMTP protocol which is the simple mail transfer protocols now let's move on to the next layer the next layer is known as the presentation layer the presentation layer is responsible for performing conversion tasks over the data that is received from the application layer the conversion of data is done in accordance to the required format it also performs encryption over the converted data so as to prevent it from getting hacked by cyber criminals or hackers the compression of the encrypted data is also performed by the presentation lab so that it can be passed on to the session layer the next layer in the OSI model is known as the session layer in this layer the communication Channel between two different devices is established the network devices are individually known as session the data that is transferred is to be done over these session channels that layer that is the session layer establishes and terminates these sessions in case of an error or some other unforeseen event this layer is also responsible for authentication checks regarding the data that is mean transferred and also provides data recovery options in case an error occurs over the communication Channel some model list let's take up a question the question is what is the mean action that takes place at the presentation layer and the options are First Option data segmentation second option encryption of data third option framing of data and the fourth option bit conversion of data you can provide your answers in the comment section below let's move on to the next layer the next layer in the osm model is known as the transport layer the main task performed by this layer is to break the data that is received from the session layer into different segments these segments comprises of protocols which are UDP protocol and TCP protocol along with the data that is segmented from the received data then the segmented data along with the UDP and TCP identification it transferred over to the transmission Channel where then it's further transferred to the network devices that requested for the data this layer also performs a very crucial part which is the flow control let's understand flow control over the network channel through a small example in this example the server has a capacity to send 50 Mbps of data at once whereas the receiver site has a capacity for 10 Mbps when the data is transferred from the server to the client it transfers 50 Mbps but it is impossible to transfer all this data at once due to the lower capacity on the client side which is why the flow control changes is required which is provided to the server side by the transport layer now let's move on to the network layer which is the third layer from the bottom in the osm model this layer is responsible for breaking down the segments into Data packets by adding IP address to them that it received from the transport layer these data packets are then further transmitted over to the best possible route to the destination system which are governed by the internet protocols including IP and IPv6 protocols for example if we have a data that is to be transferred to the network device too but choose the best option that is the route to be transferred over to that Network device now let's move on to the next layer in the osm model which is a data link layer this layer is responsible for maintaining and terminating the established connection between the devices over the network the MAC address in this layer is added to the data packets which are collectively known as data frames these data frames are then further transmitted over to the physical Network these are divided into two different sub layers medium access control that is Mac which controls the established connection device and the second sub-layer is logical link control layer LLC which identifies the address and provide flow control for the data this data frame has earlier told is transferred over to the physical layer now let's take a look at another question to brush up whatever we learned so far the question is which layer includes the max sub layer in the OSI model Option 1 application layer option 2 session layer option 3 data link layer option 4 transport layer you can give your answers in the comment section below let's move on to the last layer in the osm model which is a physical layer this layer is responsible and provides the physical medium over which the data frame is transferred but the transfer data is converted into bits before it's transferred the transmission of data is covered by different protocols that are embedded in the physical layer the transmission of ones and zeros format data is done it also responsible for maintaining the data quality by applying different necessary protocols and maintaining the bit rate throughout the transfer of data whether it be wide medium or Wireless medium now let's get started with the first topic that is what is an osm model to better understand the osm model's role in transmitting data from Network to another let's consider we have two networking devices between which data is being transferred the part between the devices is called Communication channel let us assume that we different operating system for the network channel to overcome such situation where the data cannot be transferred due to the different OS in the system once a model is used which uses the seven layer structure to allow the conversion of data from the upper model to the data that is to be transferred now let's take a look at the technical definition of the USM model the osm module stands for Open System interconnection model a specifically designed set of protocols and standards governing the data's modeling and conversion of proper transmission the oyster model is divided into seven layers which perform specific functions and apply protocols to maintain data quality without any error now let's move on to the main heading for the session that is what is the physical layer the physical layer which provides and is responsible for physical mode between the sender and the receiver node in the data transmission this layer converts frames received from the data link layer into bits that is in terms of ones and zeros to be transferred it is also responsible for maintaining the data quality by applying necessary protocols and maintaining the bit rate through the data transfer using wired and wireless medium now let's move on to the attributes of the physical layer the physical layer has multiple attributes which is applies in the USM model the first is signals the data is to be converted to signals for efficient data transmission where it has two different types digital signals represents the network pulses and Digital Data from the upper layer whereas the analog signal is converted data for transmission of the model the next attribute is known as transmission medium the network function is damaged without proper conversion at the physical layer it has two different types wide medium the connections tab list is made through application of cables example fiber optic cable and coaxial cable and the second type is wireless media connections established using the wireless communication Network example Bluetooth and Wi-Fi the other attributes of the physical layer are data flow which is defined as a rate of information flow and the transmission wireframe the factors that affect data flow rate are error rate receiving incorrect data due to noise in the transmission encoding encoding data for transmission over the network channel and the last is bandwidth that is the transmission rate of data in the channel the last attribute of the physical layer is noise in transmission during data transmission the transmitted data may get damaged or corrupted due to multiple reasons some of which are mentioned as dispersion in this case details is spread and overlapped during transmission which causes damage to the original data then we have attenuation which is the gradual weakening of the Network signal over the transmission Channel then we have data delay the transmit is data reaches the destination system outside the time specified now let's move on to the role of the physical layer in a model the physical layer due to data transmission ability performs multiple roles which are the data bit are converted to physical signals and transmitted over the channel by the physical layer it also integrates multiple electronic sockets for data transmission and apply different technological Hardware it is also responsible for translation of data that is received from the upper layer in the ASM model now let's move on to the last setting that is importance of physical layer the physical layer is responsible for maintaining the communication between the hardware and the network model without the physical layer the conversation of data from upper layer will halt which leads to collapse of the communication model it also handles data flow rate of the data being transmitted along with the time frame of the transmitted data with this we have covered all the important points and definitions related to the physical layer in the osm model let's get started with the first heading what is the OSI model The OSI model stands for open system interconnection Model A specifically designed set of protocols and standards governing the data's modeling and conversion for proper transmission The OSI model is divided into seven layers which perform specific functions and apply protocols to maintain data quality without any error now let's move on to the main topic for today's session which is about what is the physical layer the data link layer is responsible for maintaining and terminating the established connection between the devices over the network it has two sub-layers the first one is the medium access control which uses the Mac addresses from the devices to transfer data between them the second layer is The Logical link layer which identifies checks flow control and performs the error check for the transmitted data advancing let's take a look at the functions provided by the data link layer but before we begin let's understand the data flow between the data link layer and other layers in the OSI model that is to begin with the network layer we'll share the data packets with the data link layer the data link layer handles these data packets by integrating them with frame structure where the frame acts as the header for the data packet the data packet will contain information about the destination address sender address and other related Services the final product of the data link layer is known as the data frame which is then transmitted to the physical layer of the OSI model now let's take a look at the list of functions provided by the data link layer first is framing framing acts as a header format for the data then we have addressing which handles the physical address of the data frame next is flow control which is responsible for maintaining proper data exchange between the sender and the receiver side continuing with access control which handles the communication link between multiple network devices the last function is error control as the name suggests ddl provides error control services to the data now let's take a closer look at all the data link layer functions the first one is framing the data packets received from the network layer are encapsulated in frames by the data link layer for bit to bit sharing over the channel it is also responsible for restructuring the framed data in the network model and each data frame is different from the others followed by that we have addressing the task of adding a physical address to the frame in the header format is known as addressing it acts as the identification service for transmitting the frames to multiple Network models over the channel the next one is the flow control during the data transmission the data flow of the sender or the receiver side may be different causing Network congestion in the channel the data link layer in such situations acts as a flow control for the sender side to prevent the Overflow at the receiver's side followed by that we have the access control in this network model when multiple devices share the same Communication channel this leads to data Collision in the model to prevent such data collisions the data link layer performs checks on the devices with the same network channel to avoid any data loss lastly we have error control during data transmission due to noise or signal loss errors might occur in the data being transmitted to minimize such data error rate the data link layer performs error detection and correction techniques on the transmitted data error detection is done by adding detection bits in the header of the transmitted data and the receiver site can check for any error in the received data now let's take a look at the sub layers of the data link layer in the OSI model the data link layer can be divided into two sub-layers which are logical link control this is the upper sub layer of the data link layer the second one is the media access control or Mac which is the lower sub layer of the data link layer but before we begin with the details regarding the two sub-layers let's take up a quick quiz to consolidate what we have learned so far question which of the following tasks is not performed by the data links layer a addressing b i p Services C framing D Access Control you can give your answers in the comment section below now let's take a look at some points related to each layer of the sub layers the first one which is logical link control this sub layer is responsible for handling and maintaining the communication repeat this sub layer is responsible for handling and maintaining the communication between the other layers of the OSI model this layer also performs the task of overseeing the data flow rate of the channel lastly it is also responsible for handling error messages and reliability checks for the data next we have the media Access Control this sub layer manages framing of the data received from the upper layers this layer also handles the physical media for the model and interacts with the computer and IC it is also responsible for data encapsulation and media access control for the data received now the OSI model stands for open system interconnection Model A specifically designed set of protocols and standards governing the data's modeling and conversion for proper transmission the osm model is divided into seven layers which perform specific functions and apply protocols to maintain data quality without any error now let's move on to the core topic for this session what is Network layer the network layer is responsible for breaking down the segment into Data packets and resembling them on receiving end this layer also ensures that the packets are transmitted over the best possible route to the destination system governed by the internet protocols so now moving forward let us look at the networks layer function but before we begin first let's understand the data flow between the network layer and the other layers in the OSI model that is to begin with the network layer we will receive data from the transport layer of the OSI model the network layer handles these data packets by integrating them with the sources and destination address it also add Network protocol for the proper transmission over the networks Channel now let's look at the functions of the network layer first we have Internet working that handles the network channel as the name suggests then we have Network addressing followed by packet routing and packet handling now let's look at the sum of the points regarding the functions first up internetworking it is one of the main tasks of the network layer to handle the network connection between multiple devices in the channel this task applies multiple protocols available in the network layer of the OSI model for stable network connection next up Network addressing the network layer does the tasks of adding the source and the destination address in the header of the network channel the network addressing is performed to identify the device where the data is being shared next up packet routing now the establishing and routing path for the data packets is one of the main functions of the network layer in the network model a network layer chooses the most suitable path out of the line of the path available in the channel next up packet handling in this the network function the layer handles the data received from the upper layers of the OSI model the network layer converts the received data into the packets for sharing over the communication Channel now let's look at the responsibilities of network layer the network layer is responsible for handling the shortest routing path for a data packet in the network channel it is also responsible for converting the received data into packets for transmission this layer also handles the network layer protocol which is responsible for maintaining the Network's traffic in the channel The OSI model is a specifically designed set of protocols that govern communication channels through which network devices share input and data this task of sharing information is divided among seven layers of DSi model for micro level network communication now let's move on to the core topic for this session that is what is transport layer the transport layer is responsible for overseeing the data being transmitted and check there's no error in the data using different network protocols for example UDP and TCP then these data segments are shared over the connection and non-connection Network Services it also identifies suitable Communication channel for the data now let's move on to the next heading that is the functions of Transport layer before we begin with the actual functions of the transport layer let's take a look at the data flow that occurs between the multiple layers of the SR model and the transport layer to begin with the session layer will share data packets over to the transport layer where it will be checked for various errors or corruption in the data received it is then transmitted into smaller units over to the next layer in between this multiple Protocols are applied in the transport layer for example TCP UDP a CTP and then these data segments are shared over to the bottom layer now let's take a look at the functions available for the transport layer the first is process to process delivery multiplexing and deep multiplexing congestion control flow control and lastly error control let's move on with each of them in detail the first is process to process delivery function in this function it is one of the main tasks of the transport layer that is designed to effectively deliver data segments to the correct process among all the working application over the sender site this task applies a 16-bit port number to identify the sender destination application correctly to transmit data over the network channel now let's move on to the next function that is multiplexing and demultiplexing the first term is multiplexing it is also one of the core tasks of Transport layer to allow simultaneous use of multiple networks over the sender side and this is known as multiplexing whereas demultiplexing is executed at the receiver end to obtain data from multiple senders application now let's move on to the next function that is congestion control this function is used to handle traffic of data in the network model which arises you to access data being transmitted over the network channel the congestion control of data is handled in two parts the first is open loop control which is applied to stop congestion condition in the network channel whereas the second control is known as close loop control that is applied to eradicate the congestion situation in the network model now let's move on to the next function in the transport layer the next function is known as flow control the transport layer performs flow Management Services in the TCP Network model in a communication Channel this channel applies the sliding window protocol principle to handle the data flow in the network model to know more about the sliding window protocol principle you can watch our previous videos now let's move on to the last function of the transport layer the last function of the transport layer is known as error control the transport layer also checks errors in the information received from the upper layer in the osm model error detection is performed using the checksum method or error detecting codes to check corrupted data acknowledgment and no acknowledgment services are used to inform sender if the receiver has received corrupted or damaged data through the network channel with this we have cleared all the functions related to the transport layer now let's move on to the last setting for the session that is what is TLS TLS stands for transport layer Securities the TLs service is responsible for providing enhanced security to the transport layer in the network model to ensure that the external services do not affect the data being handled in the transport layer TLS performs a main role let's take a look at some of the TLs services in the transport layer where the first is known as encryption which performs encryption procedures for sensitive data being handled in the layer next is hidden many of the TLs services are invisible to the client side and are only available to the transport layer for being used in data compatibility most TLS services are available for multiple web browser and are compatible with multiple devices with this we have cleared all the points regarding the transport layer in the SM model what is an osr model The OSI or Open System interconnection model is a specifically designed set of protocols that govern communication channels through which network devices share information and data this task of sharing data is divided among seven layers of the SI model which works at micro level in a communication Channel now let's move on to the core topic for the session that is what is session layer the session layer controls and maintains connection between devices to share data among them it is also responsible for establishing and terminating sessions in the channel it also checks the authenticity and provides recovery options for the active sessions in case of a network error now let's move on to the next heading that is functions of the session layer but before we begin let's take a look at the actual working steps of the session layer in a communication Channel recession layer received data units from the upper layers in USM model or from the communication Channel where it integrates the data with session address and the session layer is responsible for maintaining the dialog between the system that are connected in the communication Channel it applies multiple protocols for secure and safe transmission for example rtcp pptp pap after that the session data is being transferred to the lower layers in the USM model now let's take a look at the functions of the session layer whereas the first is session establishment then we have data transfer dialogue managing and synchronization let's take a look at each of the functions in detail the first function is session establishment it is responsible for establishing connections between systems also known as sessions this connection allows user to share data remote access and find handling in a communication Channel it acts as a transport connection that is accompanied in the session establishment that is the transfer connection is mapped when the session is released through this connection there are three ways of Transport connection which are one to one many to one and one to many now let's move on to the next function that is data transfer one of the core functions of the session layer is to handle exchange of data between systems in half duplex of full duplex Network Mode the session layer also allows the user to initiate data transfer in case of half duplex and simultaneous data Exchange in case of a full duplex Network model now let's move on to the next function that is dialog management the recession layer is responsible for keeping log data on which the system established connection to exchange data this is known as dialog management it also uses a token method to maintain the efficiency of The Connection by giving the token to the user sharing data in case of a half duplex mode and then transferring it along with the data to the next system now let's move on to the next function that is synchronization the session layer maintains proper interaction between systems and provides a recovery option known as the known state in case of an error it also uses synchronization points to be added in the communication channel for using a known state in case of an error with this we have completed all the mean functions of the session layer now let's move on to the next heading that is protocols in the session layer the session layer provides multiple Network protocols for security safety and efficiency between the communication systems some of the session layer Protocols are real name transport control protocol rtcp this protocol provides statistical and controls the information for an RTP session in the communication Channel then we have point-to-point tunneling process pptp this section layer protocol provides a way to implement virtual private networks also known as VPN using TCP in the network channel then we have password Authentication Protocol pap this protocol in the session layer is used as a password Authentication Protocol by the PPP control to validate users in the communication Channel with this we have completed all the important points related to the session layer in the OSI model what is an OSI model The OSI or Open System interconnection model is a specifically designed set of protocols that govern communication channels through which network devices share information and data this task of sharing information is divided among the seven layers of the OSI model which works at the micro level network communication in a network model now let's look into the next setting that is what is presentation layer the presentation layer performs the task of converting data into an uncomplicated form for the application layer it is also responsible for encrypting and decoupling data which is shared over the network model it also executes the task of compressing the data transmission over the network channel for the lower models now let's move on to the next setting that is functions of the presentation layer before we begin with the functions of the presentation layer let's take a look at the general functioning of the presentation layer to begin with the application layer will share the data with the presentation layer where the presentation layer ndsm model is responsible for handling the translation and conversion of data based on the network protocols and architecture some of the protocols applied in the presentation layer are AFP ICA and lpp after which this processed data from the presentation layer is transferred over to the session layer now let's take a look at the functions of the presentation layer the first function is data representation then we have data compression and the last is network security let's take a look at the first function that is data representation the data storage and the process is handled by the American code of information interchange and binary coded decimal in the presentation layer it takes data so that the receiver can understand the data effectively and use it efficiently it is also responsible for encrypting data for data transmission now let's move on to the next function that is data compression the presentation layer also applies multiple compression techniques to minimize the data required to present the information over the network model the compressed data is much more easier to transmit and is also transmitted at a much faster speed then we have network security the presentation layer is responsible for adding encryption at the sender and the receiver side so that the data is transmitted with proper encryption over the network model it also encrypts data sent over the network and provides multiple security protocols for maintaining the encryption state for the network model now let's take a quick recap of all the functions of the presentation layer the presentation layer is responsible for exchanging data among computer devices and applying multiple encoding techniques for safety purposes it is responsible for dealing with presentation part of the data and integrating multiple data formats for efficient data transmission the presentation layer is also responsible for formatting translation and delivery of the data shared from the upper layers as well as the lower layers in the OSI model this layer also manages high level information increasing data transmission efficiency over the network channel with this we have completed all the functions of the presentation layer now let's move on to the next setting that is Protocols of the presentation layer the presentation layer is responsible for maintaining the security of the transmitted data and ensuring that the received data is accurate and effective for the receiver end this is handled by the multiple protocols available for the presentation layer in the network model some of which are apple filling protocol AFP this protocol handles basic Network file control and is specifically designed for Mac based platforms then we have lightweight presentation protocol lpp lightweight presentation protocol provides PCP products with ISO presentation services in the network model then we have network data representation ndr this type of presentation protocol is used to implement the presentation layer in the osm model and the last protocol is secure socket layer SSL as the name suggests this protocol is applied to provide security to the data being transmitted over the network channel by encrypting the data link between the web page and the data service with this we have covered all the important points regarding the presentation layer in an osr model The OSI or Open System interconnection model is a specifically designed set of protocols that govern communication channels through which network devices share information and data this task of sharing and dividing among the seven layers of the USM model for micro level is known as the Versa functioning now let's move on to the main heading for the session that is what is an application layer the application layer acts as an interface for the user and the application being accessed it manages the protocols required by the application to present the data to the user they apply HTTP and SMTP and similar protocols for the data transmission over the network channel now let's move forward with the next setting that is functions of the application layer but before we begin let's take a look at the brief working of the application layer in an osm model to begin with the application layer we share data unit with the lower less where the work of application layer is that it acts as an interface between the user and the system applications it is responsible for applying multiple Network functions and protocols to better understand the data and edit them for the lower layers it applies multiple protocols in the network channel some of which are telnet DNS DHCP now let's move on to the functions of the application layer where the first function is Network virtual terminal then we have file transfer access and management addressing and we learn directory services let's move forward with the first Network function Network virtual terminal the application allows the user to connect user system to a Remote device to access functions and services to establish remote access for the user the application layer stimulates a terminal at the remote host let's take a look at the second function file transfer access and management the application layer through remote accessing can transfer and manage files for the user system in a Remote device the file access of files is handled in terms of file attributes such as file structure and the functions applied to the files along with the features included in the file system over the network channel now let's move forward with the next function of the application layer that is addressing the application layer to establish the connection between the network devices requires a need to access addresses the application layer handles requests from the client to the server device this is possible by using the server and the client address the server will reply to the client's address using the DNS service for addressing reasons now let's move forward with the next function of the application lab mail and directly services the application layer function is also responsible for handling email forwarding and Storage this function of the application layer is also responsible for handling access rights for Global Information on the network services with this we have completed all the important functions applied in the application layer in an OSI model Lord let's move forward with the next setting that is the protocols of the application layer the application layer provides multiple protocols providing software with multiple protocols for handling data transmission and accessing the received data over a remote access channel in the network model some of the application layers applied in a network model are telnet telnet refers to the telecommunication Network this application lab protocol is responsible for handling access filing over the internet telnet protocol uses port number 23. in the network channel then we have DNS DNS stands for domain name system the DNS service protocol is designed to translate the domain name into corresponding IP addresses over the network channel the DNS protocol uses port number 53 in a network model then we have DHCP DHCP stands for dynamic host configuration protocol which is responsible for assigning IP addresses to the host Network the DHCP protocol uses port number 67 and 68 in a network model the last protocol for the application layer is SMTP the SMTP protocol stands for simple meal transfer protocol as the name suggests this protocol is designed to handle meal transmission from one user to another user the smtv protocol uses port number 25 and 587 over the network model for transmission purposes with this we have covered all the important points regarding the application layer in nosm model firstly we'll understand what exactly is the model the TCP model is a method of sharing data and information over the communication Channel where the data has to go through each of the four layer structure of the network model where it also performs tasks such as remodeling of data efficient transmission and air related issues each layer has dedicated protocols that they enact on the transmission data now let's continue with the protocols that are used in the TCP model to understand the protocols that are used in the TCP model we'll compare it with the OSI model and if you want to know more about the OSI model you can visit a video on the simply learn Channel let's begin the topmost three layers of the OSI model which are application layer presentation layer and session layer collectively refers to the application layer in the tcbip model where they use protocols such as FTP file transfer protocol HTTP hypertext transfer protocol Tel length and SMTP which is simple mail transfer protocol then we have the transport layer from OSI model which refers to the transport layer in the TCP model where they apply protocols such as TCP transmission control protocol and UDP user datagram protocol moving on we have Network layer from the osm model which refers to the internet layer in the TCP model which apply a protocol such as IP Internet Protocol icmp internet control message protocol and arp address resolution protocol then we have data link layer and physical layer from the USM model which refer to the network access layer in the TCP module this layer doesn't exactly apply any protocol but are connected through physical medium which includes ethernet Wi-Fi and cables now that we are completed with the protocols regarding tcpip model let's take a look at the layers in detail the tcpip network model consists of different layers where the original model consists of four different layers which are application layer transport layer internet layer and network access layer then we have the updated model which consists of layer application layer transport layer internet layer data link layer and physical layer let's take a look at the layers in detail the first layer that we are going to know about is the application layer application layer this layer acts as an interface between the application and programs that require the tcpip model for communication including tasks performed by the layer such as data representation for the software application that are executed by the user and then forwarded to the transport layer the protocol supplied by this layers are HTTP hypertext transfer protocol which is used to access information available on the internet then we have SMTP simple mail transfer protocol which is used to access email related tasks moving forward we have the transport layer this layer is responsible for establishing connection between the sender and the receiver device this layer performed the task of dividing the data from the application layer into packets where they are used to create sequences which are then transferred over to the destination device it also performs the task of maintaining the data that is to be transmitted without error and controls the data flow rate the protocols that are applied in the transport layer are TCP transmission control protocol which is responsible for transmission of segments over the communication Channel then we have UDP user datagram protocol which is responsible for identifying error in the data that is to be transmitted over the communication Channel moving forward the next layer is the internet layer this layer is responsible for the transmission of data over the network channel that is they provide a proper route for the packets to be transferred over the communication Channel the protocols that are applied by this internet layer are IP protocol which is the Internet Protocol this protocol assigns a unique address to a physical system so that it can be identified on the internet then we have arp address resolution protocol this protocol is used to find the physical address of the system using the Internet Protocol address in the end we have the network access layer this layer is a combination of data link layer and physical layer from the USM model where it is responsible for maintaining the task of sending and receiving data in Roberts the raw bits are transferred from the sender side to the receiver side in the format of binary digit which are zeros and ones let's move on with the advantages of using the TCP model the TCP model assigns an IP address to each of the system that is available on the network channel so that they can be identified on the internet then they are also responsible for enacting different protocols on the data that is to be transmitted over the communication channel the tcpip model also enables the user and the system to access different format of data over the communication Channel now let's take a look at the last topic for this session which is the osm model versus a TCP model on comparing both of the network models we get The OSI model consists of seven different layers whereas the TCP model comprises of four different layers The OSI model has separate session layer presentation layer whereas the TCP model comprises of a single application layer the transport layer in the OSI model provides packet delivery protocols but in the TCP model transport layer does not provide any such protocols the osm model is implemented during network communication but in case of TCP model it is used as a reference model for the network channel network security is a set of technologies that protects the usability and integrity of a company's infrastructure by preventing the entry or proliferation within a network it architecture comprises of tools that protect the network itself and the applications that run over it effective network security strategies employ multiple lines of defense that are scalable and automated each defensive layer here enforces a set of security policies which are determined by the administrator beforehand and accessibility of the data and the network the every company or organization that handles a large amount of data has a degree of solutions against many cyber threats the most basic example of network security is password protection it has the network the user chooses the recently network security has become the central topic of cyber security with many organizations involving applications from people with skills in this area it is crucial for both personal and professional networks most houses with high speed internet have one or more wireless routers which can be vulnerable to attacks if they are not adequately secured data loss theft and sabotage risk may be decreased with the usage of a strong network security system the workstations are protected from hazardous spiral thanks to network security additionally it guarantees the security of the data which is being shared over a network by dividing information into various sections encrypting these portions and transferring them over separate Pathways network security infrastructure offers multiple levels of protection to thwart man in the middle attacks preventing situations like eavesdropping among other harmful attacks it has become increasingly difficult in today's hyper-connected environment as more corporate applications migrate to both public and private talks additionally modern applications are also frequently virtualized and dispersed across several locations some outside the physical control of the IT team Network traffic and infrastructure must be protected in these cases since assaults on businesses are increasing every single day we now understood the basics of network security but we need to understand how network security works in the next section in slightly more detail network security revolves around two processes authentication and authorization the first person which is authentication is similar to access path which ensure that only those who have the right to enter a building in other words authentication checks and verifies that it is indeed the user belonging to the network who is trying to access or enter it thereby preventing unauthorized intrusions next comes authorization this process decides the level of access provided to the recently authenticated user for example the network admin needs access to the entire network whereas those working within it probably need access to only certain areas within the network based on the network user's role the process of determining the level of access or permission level is known as authorization today's Network architecture is complex and faces a threat environment that is always changing and attackers that are always trying to find an extraordinary vulnerabilities these vulnerabilities can exist in many areas including devices data applications users and locations for this reason many Network Security Management tools and applications are in use today that address individual threats when it's just a few minutes of down times can cause widespread disruption and massive damage to an organization's bottom line and reputation it is essential that these protection measures are in place beforehand now that I know a little about network security and it's working let's cover to the different types of network security the fundamental tenet of network security is the layering of protection for massive networks and stored data that ensure the acceptance of rules and regulations and Suppose there are three types the first of which is physical security the next being Technical and the third being administrative let's look into physical security post this is the most basic level that includes protecting data and network to unauthorized Personnel from acquiring control over the confidentiality of the network this include external peripherals and routers that might be used for cable connections the same can be achieved by using devices like biometric systems physical security is critical especially for small businesses that do not have many resources to devote to security personnel and the tools as opposed to large firms when it comes to technical network security it focuses mostly on safeguarding data either kept in the network or engaged in network transitions this kind fulfills two functions one is defense against unauthorized users the other is a difference against malevolent actions the last category is Administrative this level of network security protects user Behavior like how the permission has been granted and how the authorization process takes place this also ensures the level of sophistication the network might need to protect it through all the attacks this level also suggests necessary amendments that have to be done to the infrastructure I think there's all the basics that we need to cover on network security in which our next topic we are going to go through two mediums of network security which are the transport layer and the application layer the transport layer is a way to secure information as it is carried over the Internet with users browsing websites emails instant messaging Etc TLS aims to provide a private and secure connection between a web browser and a website server it does this with the cryptographic handshake between two systems using public key cryptography the two parties to the connected in exchange a secret token and once each machine validates this token it is used for all Communications the connection employs lighter symmetric cryptography to save bandwidth and processing power since the application layer is the closest layer to the end user it provides hackers with the largest threat surface poor app layer security can lead to Performance and stability issues data theft and in some cases the network being taken down examples of application layer attacks include distributed denial of service attacks or pdos attacks HTTP plots SQL injections cross-site scripting Etc most organizations have an arsenal of application layer security protections to combat these and more such as web application firewalls secure web Gateway Services Etc now that we have the theory behind network security has been covered in detail let us go through some of the tools that can be used to enforce these network security policies the first two to be covered in this section is a firewall a firewall is a type of network security device that keeps track of incoming and outgoing Network traffic and it decides which traffic to allow ordinary in accordance to a set of security rules so more than 25 years firewalls have served Network Securities first line of defense they provide a barrier between trustworthy internal protector and regulated networks from Shady external networks like the internet at some point the next tool which can be used to bolster network security is a virtual private Network or VPN for sure it's an encrypted connection between a device and a network via the Internet the encrypted connection is the secure transmission of sensitive data it makes it impossible for unauthorized parties to eavesdrop on the traffic and enables remote work for the user the usage of VPN technology is common in both corporate and personal networks next we cover the importance of inclusion prevention systems in network security or IPS Frameworks an intuition prevention system is a network security tool that continually scans the network for harmful activity and responds to it when it does occur by reporting blocking or discarding it it can be either Hardware or software it's more sophisticated than an intrusion detection system or an IDs framework which can just warn an administrator and merely identify harmful activities while in the case of an IPS it actually takes against that activity the next tool in this section and the final one are going to be behavioral Analytics Behavior analytics focus more on the statistics that are being carried over and stored through months and years of usage some kind of similar pattern is noted but the idea administrator can detect some kind of attack the similar attacks can be stopped and the security can be further enhanced another way I've covered all that we need to know about network security the necessary tools and different types Etc let's go to the benefits of network security as a poor the first which is protection against external threats the objective for cyber assaults can be as varied as the Defenders themselves although they're typically initiated for financial gain whether they are industrial spies activists or cyber criminals these Bad actors all have one thing in common which is how quick clever can cohort the attacks are getting a strong cyber security deposit that considers routine software updates May assist Works in identifying and responding to the abuse techniques tools and the common entry points the next benefit is protection against internal threats the human aspect continues to be the cyber security system's weakest link inside the risk can originate from current or former workers third party vendors or even trusted partners and they can be unintentional careless or downright even aside from that the rapid expansion of remote work and the personal devices used for business purposes while even iot devices in remote locations can make it easier for these kind of threats to go undetected until it's too late however by proactively monitoring networks and managing access these ranges may be identified and dealt with before they become expensive disasters the third benefit is increase productivity it is nearly impossible for employees to function when Network and personal devices are slowed to a crawl by viruses and other cyber attacks during the operation of website and for the company to run you may significantly minimize violations and the amount of downtime required to fix the breach by implementing various cyber security measures such as enhanced firewalls by the scanning and automatic backups employee identification of possible email phishing schemes suspicious links and other malicious criminal activities can also be aided by Education and Training another benefit is brand trust and reputation customer retention is one of the most crucial elements in business development customers today pays a premium on maintaining brand loyalty through a strong cyber security stance since this is the fastest way to get other businesses back get referrals and sell more tickets overall additionally it helps manufacturers get on the vendor list with bigger companies as a part of the supply chain which is only as strong as its weakest link this opens possibilities for potential future endeavors and development it's all really so all for the theoretical part of network security after covering so many topics let's go through a small demonstration to drive homeless of its importance so what are the first things we're going to cover is the installation of nmap what we're using right now is actually VMware career running an instance of a Linux distribution known as parrot security operating system security OS is a Debian based Linux distribution that is Catered more towards ethical hackers and beneficial testers the Howard is created mode is it comes pre-installed with a lot of tools that ethical hackers need including nmap so let's say you're using another Debian based error distribution if you want to install nmap you can go with the command of sudo apt which is the package manager installed and Mac and just press enter at this point it's going to ask you for your administrative password because of the pseudo command which you have used now this apt will change depending on the distribution let's say using a distribution that is based on our students that will be different if there is some other distribution which is built from scratch the commands will differ but more or less a lot of the distributions the mainstream distributions and people use like Ubuntu sorry noise Max cement they are Debian based so you're just going to be using sudo apt install nmap if you give your administrator password Here it's going to see that nmap is set to manually installed and it is already the newest version at this point if you do not have nmap in your distribution it's going to install the necessary package files if I just use the nmap command you can see some helplines where it basically says what kind of flags you can use for some of the most common commands the version Etc it gives a small sample for the usage of nmap no the first one of the most basic functions of nmap is to identify active hosts on your network nwap does this by using a ping scan or sometimes it's called a paint swing this identifies all of the IP addresses that are currently online without sending any packets to these hosts to run the command we're just going to go let me just clear the screen for now another thing you have to do before running nmap just for our ease of use is we're going to use the sudo Su command this will turn our console into an administrator console so let's say we want to use some drivers or some action adapters or anything that requires administrative permission we don't have to use the admin password again and again foreign has changed into a hash symbol which means we now have root access of this console right now of this terminal so what we're going to do for the pink C where we have to check existing course is we're going to use the command in map minus s p and go with the IP address of the current subnet that you are in which is always going to be minus 1 2 which always going to be 192.168.1.1 the 24 pack so this is going to take some time considering this is going to check all the hosts in this particular subnet the command then returns a list of posts on your network which is this and the total number of assigned IP addresses if you can spot like any IP addresses that you cannot account for in your network OS server you can then further commands to investigate them further using nmap itself now coming to another feature of NF which is a very important usage is when scanning posts and map commands can use server names IP addresses or even six addresses a basic and map command will produce information about the given host so to run a basic board scan we can just use the nmap command with that IP address of the device or the IP address that we are targeting the port now the host machine that I am using currently has this current IP address if you can see the current IP address is 192.168.1.22 as it's written in the ipv for address preferred section so now we're going to try and attack this host machine using nmap on parent security operating system so we're just going to go with the end map 192 what's it say 122 and press enter and it's going to start scanning the host for different services and IAP address that are being done on this store the speed of these scans usually depend on how quick the processor is and also how quickly the two machines can connect with each other but two machines I mean the virtual machine in this case and the Machine that is being attacked which is right now the post machine which is running VMware Workstation as you can see the host scanning is complete for this particular IP address and you can see the number of ports is mentioned and the services that these posts are used for is also mentioned it says which of these are open for example 53 TCP Port we can see it is closed while some of the other ports are open now one more feature of nmap is the ability to guess the operating system of the IP address that we are attacking for that we need to add one more flag which is going to go with the normal command is nmap minus o and the regular address that we are in the processor attacking just give a few minutes to run the scan and it will try and put a small case on the operating system that this host might be running this guest might not always be accurate but it puts a small idea and this is much more accurate in the case of actually Unix based operating system other than Windows based operating systems it may be able to detect that if it is a Windows a Linux MacIntosh and so on but it may have difficulty finding exact single versions which it becomes easier in the case of Linux because we can identify different distributions by some of the kernels which under most of the vulnerabilities comes from the kernels and not the particular distributions as you can see the OS detection guess is complete and you can see aggressive OS cases over here which is Microsoft Windows XP Service Pack or Windows server and there's the 98 guess that is mostly uh like I mentioned if you can guess if it is a Windows based system you can apply the vulnerabilities and the exploits accordingly now at times you may need to detect service version and the and similar information from the open ports actually this is useful for troubleshooting and scanning for vulnerabilities or Locating Services that need to be updated considering a lot of the new updates are used to fix these kind of open vulnerabilities so the flag that we're going to use in this case is minus SV or hyphen SV so only this is going to change with the nmap and the IP address of the host systems staying consistent a lot of the services that are being run on these ports are often not the most say for example Apache web server which is a very common web server being used for even local and Global projects a lot of the older versions used to have systems that can allow privileged escalations or other vulnerabilities that can allow hacker to get into your system without even impacting a trace of it celebrated versions tend to fix these as quickly as possible and most of these versions do not circulate in the real world but can be used for ethical hacking and testing on how these benefits and how these vulnerabilities can be attacked further now with the SV command scan is complete you can see that it is mentioning some of the version of the services that are being run on the particular post once again like I mentioned using these version numbers you can identify particular vulnerabilities and use the exploits designed for these vulnerabilities to gain access to the system another thing that nmap does well is sports scanning which are the basic utilities actually that nmap offers and consequently there are few ways that this command can be customized further for example to come to start a port scan we're going to use the flag of my iPhone P we're going to specify a random port for example 443 which we know it will be open because it is the port used by https connections which is obviously essential for you to access the internet and once again we are going to use the IP address for localhost as the test machine that are being attacked as you can see it clearly states that the 44th report is open as expected now you can use multiple ports you can check multiple ports this way for example and map hyphen people will scan three different ports 443 80 and 445 I'm going to use the same IP address again and it's going to show the state of all the three ports now you can see this Filter part here which does not mean it is open and it cannot be exploited in any way at least right now maybe if there is any other survey that is being run it can be exported further but right now it is in a filtered condition that is how we can actually scan for monitable ports together you can also we can also use actually in a sport can in a Range format for example let's say we're going to scan the ports from 200 to 300. once again going to use the hyphenkey flag then the IP address of the system being attacked it's going to scan all the posts from 200 to 300 and mention what are the ports that are open filtered or just straight up closed as you can see all the 101 stand ports are ill ignore state for example if we try to scan a range in the more reasonable range for example uh four four three two four percents that's it will give the IP address similar and you can see two of them are open and two of them are filtered for different reasons this is how you can find out which of the posts are reliable for exploitation before attacking these kind of devices imagine our houses without a fence or boundary wall this would make our properly easy accessible to trespassers and robbers and place our homes at Great risk right hence fencing our property helps Safeguard it and keeps trespassers at Bay similarly imagine our computers and networks without protection this would increase the probability of hackers infiltrating our Networks to overcome this challenge just like how boundary walls protect our houses a virtual wall helps Safeguard and secure our devices from Intruders and such a wall is known as a firewall the firewalls are security devices that filter the incoming and outgoing traffic within a private Network for example if you were to visit your friend who lives in a gated community you would First Take permission from the security guard the security guard would check with your friend if you should be allowed to entry or not if all is well your access is granted on the other hand the security guard would not Grant permission to a trespasser looking to enter the same premises here the entry access depends solely on your friend the resident's discretion the role of the security guard in this case is similar to that of a firewall the firewall works like a gatekeeper at your computer's entry point which only welcomes incoming traffic that it has been configured to accept firewalls filter the network traffic within your network and analyzes which traffic should be allowed or restricted based on a set of rules in order to spot and prevent cyber attacks your computer communicates with the internet in the form of network packets that hold details like the source address destination address and information these Network packets enter your computer through ports the firewall works on a set of rules based on the details of these Network packets like their Source address a destination address content and port numbers only trusted traffic sources or IP addresses are allowed to enter your network when you connect your computer to the internet there is a high chance of hackers infiltrating your network this is when a firewall comes to your Rescue by acting as a barrier between your computer and the internet the firewall rejects the malicious data packet and thus protects your network from hackers on the other hand from trusted websites is allowed access to your network this way a firewall carries out quick assessments to detect malware and other suspicious activities thereby protecting your network from being susceptible to a Cyber attack firewalls can either be Hardware or software software firewalls are programs installed on each computer this is also called a host firewall meanwhile Hardware firewalls are equipments that are established between the Gateway and your network Linksys routers are a good example of a hardware firewall besides this there are other types of firewalls designed based on their traffic filtering methods structure and functionality the firewall that compares each outgoing and incoming Network packet to a set of established rules such as the allowed IP addresses IP protocols port number and other aspects of the packet is known as a packet filtering firewall if the incoming Network traffic is not for the predefined rules that traffic is blocked a variant of the packet filtering firewall is the stateful inspection firewall these types of firewalls not only examine each Network packet but also checks whether or not that Network packet is part of an established network connection such firewalls are also referred to as Dynamic packet filtering firewalls our next type of firewall is called a proxy firewall this draws close comparison to how you give proxy attendance for a friend like how you take the authority to represent your friend the proxy firewall pretends to be you and interacts with the internet they come between you and the internet and thereby prevents direct connections this protects your device's identity and keeps the network safe from potential attacks only if the incoming data packet contents are protected the proxy firewall transfers it to you they are also known as application Level Gateway the firewall can spot malicious actions and block your computer from receiving data packets from harmful sources in addition to preventing cyber attacks firewalls are also used in educational institutions and offices to restrict users access to certain websites or applications it is used to avoid access to unauthorized content cyber crimes are today making headlines every day and individuals and companies must do everything possible to secure their information hence using security devices that helps Safeguard our networks from falling prey to deadly cyber attacks is the need of the hour what is ipsec ipsec Internet Protocol security is defined as a set of framework and protocol to ensure data transmission over a network channel this protocol was initially defined of two main protocols for data security over a network channel which work authentication header which is responsible for data integrity and anti-replay services and the second protocol is encapsulating security payload in short ESP which includes data encryption and data Authentication now let's move on to the next setting that is why do we use ipsec in a network ipsec is used to secure sensitive data and information such as company data clinical data Bank data and various sensitive information regarding an institution which I use during data transmission over a network channel the use of vpns that are virtual private networks and apply ipsec protocols to encrypt the data for end-to-end transmission let's continue with why do we use ipsec services also used to encrypt data for application layer in the osm model and provide security for sharing data over Network routers and data Authentication let's take a look at the working of ip6 services to begin with we have two different systems system one and system 2. which will establish a network channel and then the encryption of data will takes place when one host will share the data to the second host during this ipsec services will secure the data that is to be transferred over the network channel by applying router encryption and Authentication now let's move on to the next topic that is components of ipsec the ip6 services comprises of multiple protocols that ensure the data transmission over the network channel the first one is encapsulating security payload protocol in short ESP this protocol of Ip security provides data encryption and authentication services and it also authenticates and encrypt the data packet in the transmission Channel moving on we have authentication header in short ah similar to ESP the authentication header also provides all the security services but it does not encrypt the data it also protects the IP packet and adds additional headers to the packet header the modified IP datagram looks this way where the IP components are included at the second position the seventh position and the sixth position along with the authentication of data services over the network channel moving on we have internet key exchange Ike this protocol provides protection for Content data and also changes the attribute of the original data to be shared by implementing sha and md5 algorithms they also check the message for authentication and then only is forwarded to the receiver site for example this is the original data packet we are used to with IP header part TCP UDP and data whereas this is the modified ipsec data packet where ESP header is added between IP header and the TCP protocol now let's move on to the next heading that is modes of ipsec there are basically two types of ipsec modes available for data transmission over the network channel where the first one is tunnel mode this mode of transmission is used to secure gateway to Gateway data it is applied when the final destination of the data is to be connected to a sender site through a connection Gateway over the internet for example we have two hosts host a and host B through the host a we are sending a message to host B which will pass through a Gateway at host a point and it passes through a gateway to goes B then this is a basic format for Gateway to Gateway data transmission and the given IP datagram format is used for tunnel mode now let's move on to the second mode of ipsec that is transport mode this mode of ipsec is used to protect protocols like TCP or UDP and is used to ensure end-to-end communication unlike tunnel mode the transport mode data at authentication header and encapsulating security payload for security purpose in the IP header this is the modified IP datagram for transport mode the point to be noted is the ipsec header is always added between IP header and TCP header now let's move on to the last setting for the session on ipsec that is the working steps involved in IP security in general there are five steps involved in the working of ipsec to ensure data transmission over a network channel the first step is host recognition in the first step the host system will check if the packet is to be transmitted or Not by automatically triggering the security policy for the data which is implemented by the sender side for proper encryption then the second step is known as Ike phase one in this step the two host devices the sender and the receiver site will authenticate each other to establish a secure network channel it is comprised of two modes the main mode this provides much better security with a proper time limit and the second mode known as aggressive mode as the name suggests it establishes the ipsec protocol much faster in comparison to main mode let's move on to the third step which is Ike phase 2. after the second step the host decide the type of cryptography algorithm to apply over the session in the network channel and the secret key for the algorithm to be used to encrypt the data for transmission then we have ipsec transmission this step involves the actual transfer of data over the network channel using various protocols used in ip6 security which are implemented under the tunnel condition and the last step is ipsec termination after the completion of data exchange of session timeout the ipsec terminal is terminated and the security key established is discarded by both the host system what is Network address translation the motive behind implementing Nat is to allow several network devices to connect to the Internet by single public address the NAT model is a method to conserve IP addresses by using a unique address to represent the whole private Network and the mentioned public IP address is a globally recognized IP address to access the internet let's move on to some more details regarding Network address translation the task of nat process is to translate a private IP address in a network to a globally recognized public IP address and vice versa that is the same process begins from public IP address to a private IP address this task is performed by a router or a Nat firewall let's move on the flow of this process is something similar like the router configured acts as an interface between the private and network and the public network that means the private network will communicate with the router when it wants to access an internet same is the case for public addresses too when the public address wants to communicate with the private Network the router will convert it to a private network ID and allow us to access the internet the reason behind applying math process is to conserve public IP addresses to be more specific it's ipv4 addresses and it also provides much better security to the network now let's move on to the next topic Nat addresses there are different types of terms used in that process more specifically there are some addresses information that are necessary to understand the process which takes place during Network translation we will discuss them one by one let's take a look at the first address before we begin let's take a look at the example this is a general or any simple form of nat translation process we have a private Network a private device a router a public network that we can access Internet through the first term that is used is known as inside local address this IP address represents the host of the private Network and this cannot access the internet directly unless provided by an ISP server after we have the inside local address through the private Network we share it with the router when the router receives this private network ID it converts it to the public network that is known as inside global address this IP address represents the whole private Network for the outside Network and is used to access the internet for the private Network now let's move on to the remaining IP addresses for Nat according to this example now we are returning from a public network to the private Network please keep that in mind according to this the address type next comes up as outside global address this IP address represents the outside Network address for the host before that process took place then we have outside local address this IP address represents the actual address representing the host on the internet after the net process takes place now let's move on to the next setting and the topic choose from over 300 in-demand skills and get access to 1 000 Plus hours of video content for free visit skillup by simply learn click on the link in the description to know more types of math there are different types of nut available on the Internet or in the network channel but we will discuss three generally used ones where the first one is known as static Nat according to static Nat process in the given private Network each device will have a particular or a single IP address publicly designed to them that means if you have two devices in your private Network you'll have two different types of public IP addresses for each of those IP addresses that is available in your private Network due to this property of the static Nat process it is also known as one to one Nat and it's mostly used for personal addresses for example please take a look at the diagram below if we have a single IP address in a private Network we will have a single public IP address for the same again if we have another private IP address in the private Network we will have a public IP address for the same this represents static Network let's move on to the next one the next type of map process is known as Dynamic Nat for the dynamic Nat process private Network addresses is translated to public addresses from a pool of public IP addresses available to the communication Channel that is something similar to this according to the example if we have two private addresses available in the network then we have two pool of public addresses too out of which we can convert the private address to a public address and for example if we have a third private address and only two possible public addresses pool then the third address is dropped let's take a look at the diagram for a clarification this is the pool of public addresses available for this network out of which we converted 192.168.32.10 to 213.18.123 to point hundred now let's move on to the last type of nut available this Nat is known as port address translation in Port address translation of Nat the process takes place something similar like this all the available private IP addresses in the private Network are converted to a single available IP address publicly recognized that means if you have five private networks in your available Network you will have a single public IP address available to all of them due to this nature of this process it is also known as not overload but the catch is all the addresses in the private network available will have different port number assigned to differentiate between them for example 192.168.32.10 is translated to 213.18.123.100.11 where 101 represents the port number similarly for the second private Network we have 192.168.32.12 which translates to two one three point one eight point one two three point hundred that is similar with the earlier case but the change comes over 0.102 that is the port number assigned to the second private address now let's take up a small quiz to refresh all the topics that we read so far and the first question is what does outside local address refer to in that your options are name of insight Source address before translation name of destination host before translation name of inside host after translation name of outside destination host after translation please read the options very carefully to answer this now let's move on to the next question and the question is Pat address is also termed as part refers to port address translation option a static net option b121 Nat option C Nat overload and option D not overlapping you can give your answers in the comment section now let's move on to the last heading for this session that is advantages and disadvantages of applying Nat in a network channel let's take a look at the first advantage of using net mat provides privacy and security measures to the private address as it converts a private address to a public address through which we can prevent a ID from being hacked over the internet let's move on to the next advantage that process is applied to conserve approved IP addresses over the network channel as discussed earlier in the previous slides net process helps to conserve us ipv4 addresses now let's look into some disadvantages of applying Nat in the network channel and the first disadvantage is net translation leads to part delay and prevent some applications to lose their access over the network channel now let's take a look at the second disadvantage according to the NAT process router is a one that translates a private address to a public address or vice versa during this process it does happen to tamper with the port numbers as we already discussed but according to the rules set by the network channel router is not usually allowed to hamper with the port numbers but it has to because of nat let's begin with the introduction to the network hub a network Hub is a device that is designed to connect multiple Network units in a closely connected Network channel so hubs are also were used in Lan Networks the network Hub shares data with the destination device by acting as a central connection point of data transmission and connecting all the other devices in the channel some points to remember about the working of a hub Hub is incapable of processing any complex protocols due to the absence of intelligent unit in the system also the physical model of the Hub is composed of multiple sockets for connecting network devices now let's move on to the working of a network hub for the first scenario we will assume that a message is being sent through the Hub to a destination node let's begin according to the example Hub has received a message for device a where it will share the same message to device a which is a basic protocol but due to the absence of any intelligent unit or a processing point in the hub device it will share a message for a to all the other connected devices that are device p as well as device C this creates a lot of access of traffic in the network channel now let's move on to the second scenario which is when receiving a response from the device in this case when the device a shares a response to the hub to be sent to the sender device it will share the same response to all the other connected devices again due to the same reason that is lack of any Processing Unit or intelligent point in the network channel please take a look at the arrow points which is very important during the transmission of data with this we have clear all the points that are important for a network Hub now let's move on to the next topic that is information on switches the network switch is a networking device that is active in the data link layer of the OSI model and is designed specifically to connect private networks in a lan Channel switches are programmed to share messages only with the designated device that is mentioned in the header format of the message which cuts down the network traffic in the channel switches uses different types of data which can be either packets or data frames switch uses destination Source address and the destination address for forwarding the message to the specific device in the system now let's look into the working of a network switch the first scenario is when the message is received to a switch and is to be forwarded to a particular device in this case we are receiving a message for device a which will be shared only to device a according to the address mentioned in the header format this decreases the network traffic in the channel and also prevent the access of message to device B and device C this task of managing the address and sending the data to the designated device is handled using Mac address which is used by the network card installed in the network device now let's move on to the second scenario that is receiving a response from the device in this case the switch will receive a response from device a which will be forwarded to the sender's address mentioned in the message and this will prevent the response to be shared to device B and device C due to the presence of a processing unit in the switch with this we have completed all the important points to be known regarding a network switch now let's move on to the third topic that is information on routers let's begin a network router is a device that is designed to share data between multiple networks at a much larger scale in comparison to a hub or a network switch it is connected to multiple devices at a very large level that can be considered as metropolitan area network or a wide area network router uses IP addresses to share data with a specified device in the network channel and they also perform the task of translating an address that is available in a private Network to a globally recognized Network so that it can access Internet which is known as Nat Network address translation if you want to look further in the translation process that the router performs you can visit our video on the same in the simply learn Channel now with this we have completed all the introduction points regarding a network router now let's move on to the working of a network router in this scenario a message has been received by the router for device a from which it will deduce the IP address for the device a and share the data the message deliver efficiency is highest in case of a network router as it uses routing path from a routing table to guide the message to its destination point and vice versa with this we have completed all the important points regarding a network router now let's move on to the last setting for this session that is difference between a network Hub switch under router for this difference we will use different features to differentiate the working of a hub switch and a router the first difference is based upon the OSI model layer in case of a hub it is active in the physical layer of the OSI model that is also known as the first layer and in case of a switch it is active in the data link layer of the OSI model also known as the second layer whereas a network router is active in the network layer of the SI model also known as the third layer now let's move on to the next difference that is based on addresses used by each of them let's take a look a hub as we already discussed doesn't use a MAC address or an IP address for the transmission of data in the network channel in case of a switch it uses Mac addresses available in the network channel to provide a guidance system for the message to be transferred whereas in case of a router it uses IP addresses to transmit the data to the designated device let's move on to some other differences that is format of data used in each of them Hub uses electrical signals or bits for data transmission in a network channel whereas such uses a data frame or data package for the transmission of data over the communication Channel and in case of a router it uses data packets to be transferred and the next difference is based on the mode of transmission let's take a look for this a hub is based on half duplex network connection that means at a certain point of time only a single device can share or receive data from the other endpoint of the network channel and in case of a switch it is full duplex network connection that means it can simultaneously receive and send a data packet or a data frame to any of the network devices connected in the system similarly a router is also based upon the full duplex network connection form let's move on to the next difference that is installation purpose on the basis of installation purpose a hub is mainly preferred in a lan Network or in a private Network where two to three devices are to be connected which increases the efficiency due to the absence of a processing unit in a hub as for a switch it connects multiple Lan networks or a large area network available as for the case in a network router it is a Global Network that connects multiple devices across the globe and is also designed to connect internet to any of the device let's take a look at the next difference that is device classification in case of a hub it uses broadcast format or a broadcasting device to transmit data over the communication Channel due to the absence of any Processing Unit in the system and in case of a switch it uses multicasting application for the transmission of data and in case of a router it uses routing path from a routing table to transmit the data in the communication Channel let's take a look at a few more differences that is installation cost a network Hub can be installed very easily in a network channel as it does not perform any complex task in case of a switch it required moderate cost installation as it performs some complex queries or complex protocols in the network channel whereas in case of a router it is the most expensive to install in the network channel due to the high device picks and the Performance Based protocol and the next difference is based upon processing and intelligence now that we are clear a hub device does not have any Processing Unit or intelligence point and is the most basic point of data transmission whereas in case of a switch it possesses a processing unit to differentiate the destination address or a source address in the header format of the message whereas in case of a network router it is a more sophisticated device among all the three network devices as it performs the most complex queries and protocols in the network channel what are switching techniques switching techniques are network techniques responsible for overseeing the transmission of data over different communication channels they are also responsible for choosing the best route for data transfer next we will look into why to apply these switching techniques using the switching techniques we can choose the best and the most efficient route for data transfer in the network for example if we want to send some data from node a to node B we can do so by moving from node a to a switch then node D then to node B but doesn't this seems like too long this is where the switching techniques plays its role using the switching Technique we can choose the smallest and the most efficient way that is no day switch then to the node B next we will look into different types of switching techniques switching techniques can be divided into three primary types the first is circuit switching that requires a predestined path for data transmission then we have message switching which integrates the destination address with the data for transmission and in the end we have packet switching that divides its message into smaller units known as packets packet switching can further be divided into two different types that are virtual switching and datagram switching now let's look into some details regarding each of the types on the first note we have circuit switching in circuit switching for data transmission to occur a pre-established path is required between the sender and the receiver node for example assume that we call someone then this request is sent over to the network searches and a root is to be established for the signal to pass through after that system assigns a route for the signal to pass through then the receiver receives the call from the caller side this is how it works now let's look into some points to remember about socket switching for circuit switching we require a dedicated Channel established between the source and the destination node for the network to pass through the data transmission can take place only after the path established and the last point to remember is other than the sender and the destination node no node can interfere with the transmission of data to the established route let's look at some advantages and disadvantages of applying circuit switching in a network for first one we have advantages data transmission in circuit switching its sure to be established due to the predestined path circuit switching is preferred for long uncontinuous transmission of data due to the pre-established path route then let's look into some disadvantages the time required to establish the connection is quite long due to the time required to establish a path also due to the continuous transmission of data in circuit switching more bandwidth is required for maintaining the connection let's move on with message switching in message switching no predestined path is established between the sender and the destination node in the message this technique integrates the destination address into the data transmittal and shared over the network let's look into the setup to better understand the working of message switching for First Step the sender node integrates the destination address into the message then the whole message is transmitted to the switching node in the network where it gets stored for the next transmission and similarly like the Second Step this transmission of data is done over the whole network and finally through the destination address in the data it reaches the receiver's node this is how the message switching works let's take a look at some points to remember about message switching in message switching no predestined path is established it uses Dynamic routing as the message is transmitted through the communication channel in real time the each node in network switching stores the data unless it is transferred over to the next switch load let's take a look at some advantages and disadvantages of applying method switching to begin with let's take a look at the advantages the size of the data that can be transmitted over method switching is variable in message switching the use of bandwidth is done in an efficient manner now let's look into some disadvantages for message switching the nodes that are known as the switch node is to be provided with sufficient storage memory there is a delay in reaching a destination due to the message technique that is the message has to stop at each of the switch node before it is transferred over to the destination node now let's look into the last switching technique that is packet switching in packet switching the message is broken into smaller data units known as packets these packets are appended with relevant Network details for the transmission over the network let's look into the working of packet switching we know that in packet switching the data is broken into smaller units packets which each packet is given a sequence number for identification these packets are integrated with required sender and receiver address and switching method to choose the smallest route to reach the destination node these packets are then recombined at the destination node in the correct sequence order now let's look into some points to remember for packet switching for packet switching all the data packets that are provided with unique number for identification at the receiver end that is 1 2 3 and 4 in the previous example we just used packet switching chooses the most shortest part possible for the data to reach the destination in case we have unreached packet or some unattained packet the whole message from the sender site is sent again to the receiver end now let's look into some details regarding advantages and disadvantages of applying packet switching advantages of using packet switching is it provides rerouting in case the network node is busy it also allows multiple users to access the same network and no predestined path is needed the disadvantage of applying packet switching is the protocols that are needed for the working of packet switching is very complex there are often cases of lots of data packets during the transmission in case of overloading or Corruption of data the C idea or classless interdomain routing is a network concept designed to oversee the assignment of IP addresses to a system to replace the outdated way of classful addressing system furthermore using the cidm method there is low wastage of IP addresses and it also is helpful in maintaining the routing table and it performs the task of subnetting which saves a lot of IP addresses now let's move on to the next setting that is rules of using cidr to better understand the working of CID addressing in the later part please take a look at the rules very seriously let's take a look at the first rule that is the IP addresses assigned are according to the C idea are to be continuous as the ISP will provide them in a sequence to minimize the address wastage for example if we have an IP address 200.10.18.32 then the addressing will take place as 200.10.18.33 and moving on to the end position as mentioned in the example this proves that they are continuous in assigning of IP addresses let's move on to the next rule that is the number of addresses in a cidr block is to be power of two that is in case the number of addresses is odd then its invalid value for example 2 to the power 4 is equal to 16. therefore represents the number of hosts whereas if the value is 17 then it's an invalid value as for the last rule we have use of cidr block for notation purpose that is for example if we have 200 or 11.19.34 slash 28 as an IP address then the block ID of this IP address is 28. and the host ID is 4 which is calculated using 32 minus 28 because in an ip4 address 32-bit is the maximum limit now let's move on to the next setting that is working of cidr the CID are addressing applies the variable length subnetting masking that is vslm for short as the basis of its working method that is used to break the conventional IP addresses into smaller sub networks of varying sizes according to user requirement let's take a look at an example to understand the working process in the given example the IP address is 195.10.20.40 16. now let's solve the question to begin with from the giving my P address we can determine the network prefix that would be 195.10.20.40. whereas the suffix represent the slash 16 part the number 16 in an IP address represent the number of ones in the address that is known as the block ID or the network ID and the host ID is determined using 32 minus 16 because 32 is the maximum limit of bit length in an ipv4 address so the host ID is 16. and the total number of hosts that are available in the network is calculated using 2 to the power number of hosts that would be 2 to the power 16 for this case so the value is 65 536 available host in this given network ID now let's move on to the examples to better understand the working the first example is the given IP address 192.168.200.10 28 and we have to find the relevant information let's begin for the first step convert the IP address in a binary decimal format that is for this IP address it would be the given binary format now let's find out the network mask for this IP address that would be 28 once and four zeros the point to be noted is according to the slash number we point the number of ones for Network mask for example in this question we have slash 28 so the network mask has 28 ones beginning from left to right and the last four digit would be zero and in numerical form the value comes out to be 255.255.255.240. and this is the network mask for our IP address now let's move on to the next information that is network ID the network ID for the given IP address is calculated using this way by the given subnet mask that is slash 28 we assume that 192.168.200 does not change because it is a part of network ID and the point to be noted is the network ID is never to be tampered with only the host ID can be used to change the value that means we will open the dot 10 path in binary format that would come out to be zero zero zero one zero one zero then change once to zeros and perform the and operation after performing the and operation for the last four digit that is the host ID part we will get 192.168.200.0 slash 28 that represents the network ID for the given IP address similarly we can find the number of First that would be easy that is 32 minus 28 that is 4 and the total number of hosts would be 2 to the power 4 that is 16. and the first host ID in this given IP address would be 192.168.200.1 with the completion of this example we have completed all the relevant Parts regarding cidr working introduction to the algorithm the distance algorithm was invented by edscar w dextra this algorithm were designed to find the shortest path between the nodes of a communication Channel the distance algorithm is also used to form a shortest part table for the given graph and it works on the principle of greedy algorithm now let's move on to some key points regarding the algorithm the first key point to be noted to solve a distance algorithm is the algorithm is closely linked to position of the nodes in a graph the next point is the attribute value between the nodes of a channel is used to deduce the shortest path as for the last point we have the initial value of all the nodes from the current node is assumed to be infinite to much practically understand the functioning of the dextra's algorithm let's take a look at the principle for the same the principle of the algorithm works as if the distance of U that represents the current node plus the length that is the attribute value between node U that is a current node and node V that is the target node is less than the attribute value to distance of the target node and also the distance of the target node is equal to the distance of current node plus the length between Target node and the current node where distance U represents the source node or the current node and distance V represents the target node or the destination node to much better understand let's apply this for the given question let's find the shortest path in this given example we have three different nodes node a b and c using the previously discussed algorithm principle we will deduce the shortest path for node 8 to the other nodes in the graph that is the shortest path from node a to node B and the shortest path from node a to node C for this let's take the node B first according to the solution it should be for node B on applying the algorithm along with the values we have if 0 that is the position of a is zero plus the target node attribute value that is 10. is less than equal to infinite that is initially as mentioned infinite value is to be assumed and this statement stands true so the distance between node a to node B becomes 10. for the third step we will look into distance between node a to node C that would be 0 plus 40. that is the direct connection between node a to node C according to the example Which is less than infinity again true so the distance between note a to node C is 40. Moving on but we have to find the shortest path so for this fourth step comes into picture that is for node C from node B on applying the algorithm we have 10 that is the initial value of node B and plus 15 that is the attribute value between B and node C which is 25 and is less than infinity so the shortest path between node a to node C becomes 25 instead of 40 which was given through step 3. using the same scenario and same steps we will solve a much difficult question and understand how the algorithm is used then without further Ado let's move on to the solved example using the textras algorithm according to the given question we have to use the distress algorithm for the given graph and find the shortest path from node a to node C the point to be noted is we need to find distance that is shortest between node a to node C mining now let's take a look at the graph and this is the given graph with node a at the current node and node C is to be the targeted node but before we begin with the solution for the given graph let's take a look at some of the important points to remember the first point the distance of node a from all the other nodes is infinite in the starting step as discussed earlier in the example graph the next point is the node with the shortest value will become the next current node then we have this graph is done to maintain a proper shortest path value table which will be very helpful during the solution of the graph now let's move on to the solution to begin with we will make shortest path table value that is given through this with three columns in it node column value column and previous node now let's start with the actual solution to begin with the first step is to Mark the current node that is node a then the nodes that are directly connected to the current node that is node B and node d Now using the value distance that is 3 for node a to node B and 8 for node a to node D we will update our table where the point to be noted is that we have updated the previous node as a for both the nodes B and D moving on now let's choose the next current node that is node B for the next case because the shortest path in the given table is 3 which is less than 8. now the directly connected nodes to node br no D and no d similar to the case we did earlier we will Mark the shortest distance from node B to node D and OD let's reduce the distance the distance between node B to node D is 3 plus 5 that is equal to 8. and then we have distance from node B to node D that is 3 plus 6. so the value is 9. now we will update our shortest path table and the new table comes up to be from node d to node B we have 8 and node B to node e we have 9. with the previous node as B moving on let's decide the next current node that is D because the shortest distance is 8 in comparison to 9 for node e so the new current node is node D and the directly connected nodes to node D is node e and node f the point to be noted is the current node is chosen only from the unvisited nodes now for this we have distance between node D to node e is 8 that is the previous value we deduced plus 3 that is the distance between node D to node d and the total value comes up to be 11. then we have to node F from node T that is 8 plus 2 that is the distance between node D and node f so the value becomes 10. on updating the shortest path graph table we have the new distances that is node F has 10 value with the previous node as D and there is no change with the node d because in comparison to 8 11 is much bigger moving on let's choose the next current node that is node e because in comparison to value 10 from node F 9 is smaller now the node e is a current node and the directly connected nodes are node F and node C now let's find the value between node C and node e that will be 9 plus 9 that is the distance between node e and node C so the value totals from up to be 18. and for node F and node e we have 9 plus 1 that is the distance between node e and node F that comes up to be 10. now let's compare with the graph table where node f is originally at Value 10 and again the value is 10 so there's no change and see we have infinite and the value 18 is much smaller so the new graph would be something like this with node c as 18 value and previous node as e now let's decide the next current node that is node F because the distance value is lowest in the given graph that is 10 and for node C is 18. and the directly connected node is node C then the distance comes up to be 10 plus 3 that is 13. using this 13th value we can decide the current value of C is 18 and the new value is 13. in comparison 13 is obviously less so the new graphs comes out to be for node C value 13 and the previous node becomes f with the completion of all the nodes in the given graph we can deduce the shortest path from node a to node C that comes up to be from node a to node D node D to node F and node F to node C and the total value comes up to be 13. with this we have covered all the parts regarding the functioning and the working steps involved in the dikshas algorithm if you have any questions regarding the topic you can ask them in the comment section introduction to distance Vector routing distance Vector routing refers to the distance or the vector that is between the neighboring nodes in a network channel and the routing part refers to the established route through which data packets are transmitted in the network channel the other aspect of this routing protocol in a network channel is to determine the shortest path for a data packet in the network to reach its destination next we will look into some key points regarding the routing protocol for routing protocol three primary key points are to be remembered first one being each router in this protocol is designed to share the vector data of each node throughout the network this step is done to maintain proper circulation of data in the network channel the next key point is the routing pattern in the network protocol that is the data shared by the routers is transmitted only to those nodes that are directly linked to a particular router the last key point is that the routing protocol is designed in a manner that it shares the updated Vector data periodically at the network channel now let's move on to the next heading that is the algorithm used in the protocol the algorithm used in this protocol is termed as Bellman fold algorithm this algorithm defines the shortest part that the data packet can take to reach its destination node from my initial node where V of X Y refers to the least distance from a node X to node y moving on we have C of X comma V where X is caused from each of its neighboring V node is taken into consideration then we have D of v y this is a distance of each neighbor from its initial node and lastly Min or Phi this is an abbreviation used to determine the most shortest Vector after the solution is obtained using the algorithm in the next heading that is Network example we will understand all the points used in the algorithm now let's design a network model with five different nodes that are a b c and d with each node connected to each other using different network channel the numerical values in the network channel refers to the vector count that is the distance from node a to node b or to some other node in the network channel in a network model each node share its Vector data with its neighboring node at a regular interval as there are various updates in the network model this data is shared in a form of routing table where three different columns are used first being destination column second Vector column that is the distance node and lastly the Hop let's take a look at the neighboring nodes for this model for node a we have b and e as it is directly interlinked to the node a for node B we have node a and node C for node C we have B and D for D we have c and e and lastly for E we have node a and node d these nodes represents only the neighboring nodes now let's solve an actual example on routing protocol to clear all our doubts and understand the key points the example we'll be taking to solve is this network model the initial step to start solving the network model using the distance Vector routing protocol is to make routing table for each of the nodes let's make the routing table for node a this is the routing table for node a where we have destination as a that means destination is a from node a that means the distance Vector should be zero then we have destination as B let's take a look in this given example there is no given connection between A and B that means this distance Vector would be Infinity then we have destination as C similarly as node B there is no direct connection between a and node C that means this is also Infinity and same is the case with node d and in the end we have node e that is the only directly linked node to note a that means the distance given is 5 so the network Vector is 5. let's make an another routing table for node e this is the routing table for nodi let's take a look in this routing table the first is destination to node a according to the network model given distance is 5 so the vector value is 5 but the Hop to pay then we have destination as node B according to the model the distance Vector should be 4. then we have destination as node C as given this no direct connection between node e and node C that determines the value would be Infinity then we have node d which represents direct connection with node e and the value is 7. and lastly e destination from initial Point e would be zero vector now let's make another routing table similarly for node C Now using the same steps you can make the routing table for the remaining nodes that is node B and node d now let's move on to the next step in solving the routing issue this step is known as update step in this step we use the vector column from each of the node to update the vector column or the routing table for a particular node in this part we'll use node is Vector column to update the routing table for node a and the steps are using the algorithm that is the Bellman fold algorithm we used earlier as we already know moving from a to destination node a is always zero so we won't be doing this step let's move on to the next one that is moving from node a to node B that would be would be a comma e as we are using Vector column of node e plus and the distance used to reach E from B a comma e represents 5. and E to B represents 4 according to the network model so the value is 9. similarly let's solve for a to c to a to c we have a comma e plus destination required to move from E to C according to the network model we have node a is only directly linked with node e so the value would be 5 but there is no connection between node e and node C so the value would be Infinity moving on we have a to d in this case we have a comma e the value would be 5 plus e to D that is a direct connection and the value would be 7 so the total distance is 12. and the last one is a to e for this we have a comma e that is directly the neighboring node the value would be 5. so the new routing table for node a is 0 9 Infinity 12 and 5. similarly let's take another node for this for the next node we will take node C and we will update the routing table of node C using its neighboring nodes that are node B and node D according to the network model now how to do this step firstly it's C to destination a in case of node B we have C to a that would be C comma B that is a direct connection plus distance required from B to a according to network model we have C comma b as 6 plus b to a does not have any connection that is infinity so the value would be null then we have node D in this case we have C comma D that is a direct connection 3 plus d to a that is again Infinity as it is not linked directly to node a moving on we have destination as B for node B we have direct connection so C comma B value is 6. whereas for node D we have C comma D that is distance 3 plus d to B that is infinity as it is not directly linked with the node B so again the value is null then we have destination as C so connection between C to C is 0. moving on we have destination at node d that would be C to d as C to D as there is no direct connection between node B and node D so the value is infinity whereas for C to D is a direct connection for node D so the value would be 3. now for the last node that is node e in case of node B we have C comma B plus b to e where the value for C to B node is 6 and B2 is 4 so the sum is 10. and now in case of node D we have 3 plus 7 that would be distance from C to D and then D to e and the value would be again 10 so we can use any of the side to reach the destination node e by completing all the steps we have the new table for node C similarly we can find the routing table for all the nodes present now to look into some key points we learned for the initial step use only the node distance of immediate Neighbors nodes without distance that is directly linked to each other is always infinity for the update step use the vector table of the only neighboring node we have for the initial node and lastly to continue the update step roughly n minus 1 iterations are used where the value of n is equal to the number of nodes for example the model we took has five nodes that means we have to do a loop of four iterations what is hdlc let's take a look the hdlc stands for high level data link control refers to the bit oriented Network protocol design to connect multiple Network system according to the communication requirement the hdlc model applies the arq protocol for application and establishes a full duplex Communication channel between the network devices moving on we have the different types of hdlc stations available hdlc stations can efficiently be differentiated into three different types where the first type is primary station in this station it handles the establishing and destablishing of the primary data channel to share different frames in the network channel known as commands it also performs the data management for the network moving on we have the secondary station this station work under the command of the primary station and the frames issued by the stations are known as responses as for the last station we have combined station as the name suggests this type of station is available for both commands and response value next we will look into hdlc transfer models the hdlc protocol supports two types of transfer models which are applied according to the need of Communication channel where the first type is known as normal response model or in short nrm this transfer model combines the primary session and the secondary station in a point to point or multi-point configuration to exchange commands from primary station and responses from the secondary station and response to the multi connection moving on we have the second type of transfer model which is asynchronous balanced model in this transfer model the combined stations are installed in a point-to-point configuration for exchange of command or responses from either of the node moving on let's take a look at the hdlc frame model and types the data unit for sharing information in the hdlc protocol is known as frames the hdlc frame consists of multiple frame fields which may varying according to the frame type in general the hdlc frame consists of five different frame Fields where the first field is flag field in hdlc each frame starts and with the flag field in the configuration and is defined by an 8-bit octet sequence which is 0 1 1 1 1 1 0 in the flag field moving on we have the address field it encapsulates the receiver's address in the field for example if the frame is sent from the primary station it contains the secondary station's address and vice versa next we have the control field this field contains the flow and error control information in byte format next we have payload or the information field it carries the actual information from the upper layer of the OSI model and the last field is known as FCS field this field stands for frame sequence check and acts as an error detection field in the hdlc protocol which includes a 6-bit CRC check given is a frame format for an hdlc protocol with flag in the both ending and the starting point followed by address field control field information field and FCS field now let's take up a quiz to understand all the things we have learned so far the question is the hdlc protocol functions under which network layer in the USM model and the options are application layer data link layer physical layer and the network layer you can give your answers in the comment section now let's move on to different types of frame models available in sdlc the free models in hdlc can be classified of following three types depending upon the control field value of the frame where the first frame is known as iframe the iframe stands for information frame and is applied to encapsulate the user information from the upper layer in the model and then transmit it to the network channel note the first bit of the control field in this Frame is always zero which also acts as an identification point for iframe moving on we have the S frame the S frame stands for supervisory frame and is used for error and data flow control and does not contain any information regarding the information field in the format not for the S frame s the first two bits of the control field is 1 and 0. which acts as an identification point for S frame as for the last type of free model we have U frame the u-frame stands for unnumbered frame used for system management and exchanging information between connected network devices with this we have covered all the relevant information regarding the hdlc protocol the checksum is one of the most applied error detection method in the network channel and is a bit based format detection method the checksum uses checksum generator on the sender side perform the checksum method and the checksum checker on the receiver side to check whether this an error in the data or not let's continue with the next setting that is why to apply checksum method using the checksum method at the center side the checksum value is added to the original data to being transferred as an error detection method whereas at the receiver side it decodes the incoming data from the sender side according to the checksum method to detect any changes in the given data now let's move on to the working steps involved in the checksum method there are various steps involved in the checksum method let's take a look at the first step that is the first step begins at the sender site where we divide the original data into K Paths of n Bits continuing with adding all the cave blocks we have obtained then the addition result is complemented using one's complement the data now obtained is known as the checksum value next let's look at the step 2. data transmission after we have received the checksum value from the checksum method we will add it to the front of the original data and transfer it to the network channel to the receiver site now step 3 step 3 begins at the receiver site that is it will divide that is the receiver side will divide the obtained original data plus each XM value into clay box and then add all the K blocks using addition after that we will complement the obtained data if the complement of 1 comes out to be 0. that is no errors are received in the data and the receiver will accept the data whereas for case 2 if the result is not 0 the received data is damaged so the receiver will discard this data and request for retransmission of data from the sender side now after understanding all the points regarding working of the checksum method let's take a look at a solved example to better understand all the points the question is for the given data perform the checksum method this is how we divided all the four parts each of these represents a k block that is four blocks and eight bits in each of the block that is n Bits now for the first step that is at the sender side we will add all the given data so the value would come out to be one zero zero zero that would be 1. 0 1 0 0 would be one zero zero one one would be one carry 0 so 1 carry plus one means zero plus one carry again one carry plus one means zero and one carry again one zero one that is one carry 0 plus 1 plus 0 means one so one carry is over this side one plus zero is one one plus one is one carry zero zero plus zero zero zero plus zero is zero and zero and we have one carry over here so the obtained data would be one zero with extra bit as this now to resolve this issue we will now add the extra carry to the obtained data from the addition part that would be one zero one zero zero one zero zero now add the sender side you will do one's complement for the obtained addition value that would come out to be one one zero one one zero one zero that is the checksum value now this value addition to the original data will be shared to the receiver side where at the receiver side we will again perform the addition method and the value comes out to be this along with two digits of extra bit that is the carry again similarly we will add this carry to the addition value and get the new data that is all ones now again going by the steps we have to perform one's complement for this value obtained that comes out to be all zeros that means the checksum value is 0 at the receiver side which indicates that there are no errors in the received data by the receiver side with this we have completed all the points regarding working of the checksum method now to better understand all the steps let's take up a quiz that is for the given data find the checksum value where the given options can be one of them you can give your answers in the comment section what is peritable check the parity bit is a data checkpit added to the original data for detecting errors at the receiver Side by checking the Integrity of the received data the parity bit adds 1 or 0 to the original data that is to be transmitted to the receiver side and if in case there is an error in the received data the center side will do the penalty check and give the request for retransmission of the data now let's move on to the key points regarding pair debit check to properly understand the working of parity bit check we need to understand some key points where the first one is redundant bits where the extra binary width that are added explicitly to the original data to prevent the damage to the transmitted data or to detect the damage to the transmitted data they are also used to recover the original data in case of a damage at the receiver end the number of redundant bits added depends upon the type of check method used regarding which in this example there are four data bits used whereas three redundant bits it can also be two redundant widths or one redundant bit in case of parity check method only one redundant bit is added to the original data now let's move on to the next key point that is parity bits the parity weight check method is a method to add binary bits to secure the original data that is done by counting the total number of ones in the original data which is either even or odd number the parity bit check method is used to detect error in the original data at the receiver side and also in some cases it is used to correct the change there are two types of priority bits available to choose from the first one is odd predictable in this parity bit check the number of ones in the original data including the parity bit should be order number for example in the given example the number of green tiles has four ones that is even so the parity bit should be one in this case to make the total number of ones in the data 5 that is odd similarly the other parity bit is known as even parity bit in this case of parity type the total number of ones counted is to be even including the parity bit for example the number of ones in green tiles is four that is even so the value of parity bit should be 0 in this case the point to be noted is the parity bit value should always be correct because it acts as the error detection method at the receiver site now let's move on to the explained example to consolidate all the things we have learned so far the question is for the given data bit that is one one zero one one apply the even parity bit check for data transmission now let's begin for the first step let's take the original data that is one one zero one one one and the parity bit value is to be given as p now according to the next step we have to count the number of ones in the original data which will come out to be 5 bits that means there are five ones in the original data which represents an odd number to balance this according to even parity bit now we have to add 1 in place of P so the new data to be transmitted will become 1 1 0 1 1 1 and 1. which will be transmitted to the receiver site by the sender side after the data has reached the receiver side there are a few cases that may arise in the data where case one is the data we received to transmission has no errors that is the data received is correct after applying the parity with check which in this case is even so the transmitted data is this and the received data is this that means both the transmitted data and received data are same that means the received data is correct then the second case arises is the data bit received two transmission has errors that is the data received is damaged after applying the even parity check which in this case the transmitted data is and the received data has an 0 instead of one which means the number of ones in this case becomes 5. which does not match with the even parity check so it has an error and the last Case Case three in this the data bit received through transmission has errors that is the data received is correct according to the event parity bit because the transmitted data has six ones whereas the received data has four ones but according to even parity check only the number of ones should be even that means the number of ones received by the receiver side is 4 so according to parity bed check it is valid but according to the original data the received data is wrong these are the three main cases that may arise during the transmission of data through parity check method the Heming code method is a network technique that is designed to detect errors and corrects data bits which are transmitted during data Exchange it was first implemented by RW Hamming hence the name Amin code this network technique is implemented because during data transmission there are often cases where data loss or data damage occurs to recover or detect the damage in the original data we use ham encode in the next slide we will look into some terms that are related to the working of Hamming code the first one being redundant width these are the extra binary bits that are added explicitly to the original data bit to prevent damage to the transmitted data and also to recover the original data in case of a damage at the receiver end in the next point we will look into some formula related to redundant bits and how to add them in the Hamming code the formula related to redundant bits is to are more than equal to M plus r Plus 1. where M refers to the data bits in the data and R refers to the Redundant bits let's take an example in case m is equal to 4 that means the data bits used are 4 we need to find the value of r using the above formula let's deduce the value of redundant bits 2R is more than equal to 4 plus r Plus 1. 2 to the power r is more than equal to R plus 5 so using this let's use r equal to 0 if we use that we will get a value 1 that is more than equal to R plus 5 but that is wrong then using r equal to 3 that is 8 is more than equal to eight this way we conclude that the Hamming code would be 7 bit data because the value of R is 3 and M is 4. now let's move on to the next term related to harming code that is parity pills the parity bit is the method to append binary bits to secure that the total number of counts of one in the original data is either even number or an odd number let's take a look why do we exactly use parity bits they are used to detect error in the original data which occurs during the transmission of data through this method we can detect the error at the receiver end and also correct it let's take a look at different types of parity bits available first one is even parity bit in this case of parity type the total number of ones counted is to be even in the count in case the count is odd then the value of parity is 1. otherwise the value should be zero similarly the other parity bit is known as odd parity bit for this parity bit the total number of ones counted in the original data should be odd if that is the case the value of parity bit should be zero and in case the value of ones in the original data comes out to be odd then the parity value would be 1. now let's move on to the next setting that is a working example of the Hamming code let's take a look let's begin with the steps to be followed to solve a Hamming code issue the first point being the position of the parity width is determined using 2 to the power n term where n represents the number series 0 to n assigning the position for parity bit using this method would be more clear giving an example for the second point we have the remaining positions represent the data bit now let's try using the value of parity bit for n is equal to 0 that means 2 to the power 0 is equal to 1. so all the bits with one in the last position are used to determine the value of the parity bit to better understand the assignment value of parity bit please focus on this mention table in this table we can take a look at the last position that is n is equal to 0. and see the mentioned number for P1 we can use a value 1 because n is equal to 0 and the last position value is 1. then is number three because the last position beta is one then similarly for number five because n is equal to 0 and the bit value is 1. so these three parity value can be used for and is equal to zero similarly let's take a look when the N is equal to 1. that means 2 to the power 1 is equal to 2. so all the bits with one in the second position are used to determine the value of parity bit now let's take a look at the table to identify the numbers related to this parity bit value the first one being to due to the presence of one bit in the second position then we have P3 presence of one bit in the second position similarly the next would be number six due to the presence of one bit in the second position similarly let's take a look at when n is equal to 2 that means 2 to the power 2 is equal to 4 so all the bits with 1 in the third position are used to determine the value of parity bit and this would be 4 5 and 6 number please read the points very carefully because next we will solved an example to better clarify all the concepts let's move on we give an example is the data bit to be transmitted is one zero one one and we have to solve this using the Hamming code method so the first step would be applying the Hamming code method and identify the given number of data bits that would be four according to the question so the number of parity bit would be 3 where the value would be 1 2 and 4. according to the power of P expression that means we will get something similar to this this representation is in data bit format where the first position is for P1 parity bit the second for 2 to the power 1 that is 2. P2 and the third one is for 2 to the power 4 that is P4 parity and let's put the value that is to be transmitted in the remaining positions that would be P1 P2 1 p 4 1 0 and 1. using this bit value we will deduce the value of P1 P2 and P4 for data transmission in this case we are using even parity for the example that means the number of ones should be even let's take a look for P1 we have D1 D3 D5 and D7 as mentioned in the earlier slide so the value would be P1 comma 1 comma 1 and comma 1 according to the data bits available to us by the question that means the value would be 1 because the number of ones for P1 is odd so to make it even the value of P1 would be 1. similarly for P2 we have D2 D3 T6 and D7 using the same method we will get P2 1 0 1. so the number of ones for P2 is even so the P2 value would be 0. next is for P4 the value is D4 D5 D6 and D7 where P4 has 1 0 and 1 that means the number of ones is even so again P4 is equal to 0. Now using this we get the new bit that is to be transmitted that is one zero one zero one zero one after Transmission in case let's say at position 5 another Argus and the value of 1 is converted to 0. to detect this error at the receiver side we will use the Hamming code to begin with we will use the parity value to cross check the original data bit that means let's do the parity bit method for this received data so for P1 we have D1 D3 D5 and D7 so the number of ones is odd that means the value of P1 should be 1 to make it even then for P2 we have D2 D3 D6 and D7 so the number of ones is even that means the P2 value would be zero now let's move on for P4 that would be 4 D5 D6 and D7 so number of ones is one that means odd so the value of P4 would be 1. now let's take a look at the results that we obtained using this method foremost this shows that the data transmitted is damaged and we can detect the error position using this method that is using the value of parity bits obtained where this will lead to 2 to the power expression that means 2 to the power 0 plus 0 plus 2 to the power 2 that means 5. that matches with the Assumption we took now to correct this error we can use the position that we obtain that is 5. and replace the zeroth value with one bit by doing this we will obtain the original data now let's move on to the first heading that is Introduction to the protocol the stop in read protocol is a type of flow control mechanism active in the OSI model of the data link layer the transmission of data applies only to the noiseless channels where a noiseless channel represents an ideal Network channel where no frames are lost duplicated or hacked moving on we have the Stop and rate protocol is unidirection in transmission of data that is either sending or receiving data will only takes place at an instance for the third point we have the Stop and rate protocol as the name suggests is when the sender shares a data packet to the receiver end then the sender side has to stop and wait for the receiver side to send an acknowledgment before it starts sending the next data packet with this point we are now knowledgeable about the working of the Stop and read protocol at an elementary level now let's move on to the next heading the next setting for the session is steps involved in the Stop and weight protocol the steps for this protocol are divided into two parts sender and receiver protocol let's start with the sender site the first step is to transmit one data unit at a time to the receiver End by the sender site and the next step is to transmit the next data until Only After we receive the acknowledgment from the receiver end now let's move on to the receiver side in receiver side step one is to receive the data and use the data that is being sent then the second step is after the data has been used by the receiver side it will send the acknowledgment to the sender site for further data transmission this is how the transmission of data takes place in the data protocol now let's move on to the next heading that is working of stop and weight protocol using the previous two headings we can easily determine the steps involved in this working let's take a look to begin with we have two sides the sender and the receiver side the first step is to send the data from the sender side to the receiver end and after the receiver side has used the data it will send the acknowledgment signal meanwhile the sender site has to wait for the acknowledgment signal only after it receives the acknowledgment signal will it send the next data packet now that the sender site has sent the data for the second time the receiver site will use this data and then only share the acknowledgment signal this process of sending data from the sender side to the receiver side and receiving acknowledgment from the receiver side to the sender site continues for n number of times according to the given scenario in the network channel now let's move on to the next heading that is also the last setting for this session that is drawbacks of using stop and read protocol the first drawback of using this protocol is the loss of data this issue can arise when transmitting data from the sender site to the receiver end it may be due to any issue due to hacking attempt or network disruption or any other network related issue then this can also arise when receiving acknowledgment from the receiver site now let's move on to the second drawback the next issue is related to acknowledgment transmission that is during the transmission of acknowledgment signal due to the network issues technology signal is disrupted and the transmission is terminated this can arise again due to any reasons that are occurring in the network channel now let's move on to the last drawback for this heading the last issue occurs due to the delay in transmission time of the information time delay drawback can occur on either side of the transmission that is during data transmission or the acknowledgment transmission as we know in a networking concept protocols refers to the rules and instructions that governs the data transmission between different network models and devices in a communication Channel the data transmitted using protocols is easily handled and is reliable to use as well as it provides a secure channel for the data to be transmitted now let's move on to the different types of protocols available in a network channel the protocols available in a network channel can be divided into two different types noiseless channels and noisy channels where the noise part refers to any external interference data error or duplicate Transmission in the network channel furthermore noiseless channels and noisy channels can be divided into subdivisions let's take a look at the noiseless channels first noiseless channels can be divided into two types simplest type and stop in weight type whereas noisy channels are divided into three subdivisions stop and wait arq go back and arq selective repeat arq in the noisy Channel go back in arq and selective repeat arq are the ones that apply the sliding window protocol for data transmission over the network channel now let's look into some information regarding sliding window protocol to begin with the sliding window protocol is a technique that allows the share of multiple data frames in a network channel where the number of frames shared is determined by the window size assigned to the network channel also the frames sent during transmission are assigned with a sequence number for efficient train Transmission in the communication Channel till this point in the video we have already learned about the definition of what is the sliding window protocol now let's look into the working steps of the sliding window protocol to begin with we have a center site and a receiver site in the network channel then we require the frames where each frame is given a sequence number for this example we are using 0 to 8. which means a total of 9 frames are available at the sender side then using the window size we determine the number of frames that can be shared at an instance for example we'll be using three as a window size for this example let's start with sending the first frame that is zero to the receiver side after the frame is sent a sliding window appears on the number of frames now let's move on to the next that is frame one the point to be noted is before receiving any acknowledgment we have to send all the frames that are available according to the window size that is for this example the window size is 3 that means we have to send three frames before we receive any acknowledgment from the receiver side let's send the last frame that is frame 2. now we have to wait for the receiver site to send the acknowledgment signal to the sender site before we can send the next frame now that we have shared the maximum number of frames the receiver end will share the acknowledgment signal for frame 0 with the sender side after this acknowledgment is received by the sender side we can share the next frame in the list that is frame 3. after the frame 3 has been sent see the positioning of the sliding window the sliding window now changes from 0 1 2 to 1 to 1 3 frame this positioning of the sliding window represents that zeroth frame has already been acknowledged by the receiver side whereas the third frame is sent for acknowledgment from the receiver site by the sender site and similarly we have to do the same pattern for the next two frames that is frame number one and frame number two now the sender side will receive the acknowledgment for frame 1 from the receiver side and we can send frame 4 from the sender side to the receiver site now see the movement of the sliding window the sliding window changes from 1 to 1 3 frame number to 2 3 and 4. similarly we can move on to the last frame now let's draw some simple conclusion from all the working steps we have seen so far to begin with frame number one and zero represents the acknowledged frames whereas the frames within the sliding window represents the frames that are waiting acknowledgment whereas the remaining frames 5 6 7 and 8 are not yet shared with the receiver side now let's move on to the next heading for the session difference between stop and weight protocol and sliding window protocol the first comparison is on the basis of working mechanism where the Stop and beat protocol is designed to send the data frame at a single time and wait for the receiver to send the acknowledgment to share the next frame as for the sliding window protocol sender can send multiple frames simultaneously and then wait for the corresponding acknowledgment from the receiver end let's move on to the next comparison that is based on the window size on the basis of window size the Stop and rate protocol is always fixed at 1. as for sliding window protocol as we saw in earlier slides it varies according to the scenario in the network channel let's take a look at some other comparisons too the next comparison is based on efficiency and time delay as comparison on this basis the Stop and read protocol is efficiently low and suffers from more time delay as for sliding window protocol the efficiency is higher than the Stop and weight protocol which provides lower time delay during data transmission let's move on to the last comparison sorting and transmission of data for stop and read protocol sorting is not required and it applies half duplex system for data transmission as for sliding window protocol we require sorting for better efficiency and is full duplex in nature with this we have reached the end of the video now let's look into some information about the go back and arq protocol this protocol applies the sliding window method for transmission of data in the network channel where n in the protocol refers to the window size assigned in the network model as for the term arq in the protocol refers to the automatic repeat request which means the sender side will send multiple data frames to the receiver side according to the assigned window size and only after it receives an acknowledgment from the receiver site will it continue to send the frames from the sender side moving on let's look into some important points regarding the protocol as to begin with the method applied to share multiple frames from the sender side to the receiver side is known as the protocol pipelining where each frame is assigned a sequence number for proper transmission of data in the network channel now let's move on to some other important points as we already know the n in the protocol refers to the window size that is the maximum limit of frames that can be transmitted from the sender to the receiver side before reaching the acknowledgment for the previous frame and in case if the transmission of the acknowledgment of a frame is not received within a certain time period then all the frames from that sequence number are to be re-transmitted in the channel this point is to be remembered properly because this will be the key point in solving a question related to go back in arq protocol now let's move on to the working of the protocol to begin with we have a sender site and a receiver site along with the sequence number the window size for the network channel and the number of frames will already be assigned in the network Now by applying the sliding window protocol we will send the first three frames from the sequence continuously which will be frame number zero frame number one and two this is assigned according to the window size after sending the frames we will have a sliding window over the sequence number that are 0 1 and 2. after the frames are sent to the receiver site it will use the frames and send an acknowledgment signal to the sender side that would be 0 for the first time after which we can share the next frame that will be frame number three from the sender side to the receiver side after sending frame 3 the sliding window from sequence number 0 1 to 2 will shift over to 1 2 and 3. and similarly for frame number one we will receive the acknowledgment signal from the receiver side to the sender side and then we can share the next frame that is frame number four from the sender side to the receiver side and the sliding window will shift over from sequence number 1 2 and 3 to over 2 3 and 4. as for the next frame that is frame number two when we receive the acknowledgment from the receiver side there is a catch for any network issues the acknowledgment is not received by the sender site so in this case as discussed earlier in one of the important points the sender side will not transmit frame number five instead it will re-transmit frame number 2 3 and 4. where the second frame is the one which did not receive the acknowledgment and all the frames sent after second frame is to be retransmitted along with it that is 3 and 4. to much better understand the solution for the example we'll be solving later in the video it is suggested that you watch the steps involved in the working of the go back and arq protocol again now moving forward let's take a look at some of the advantages and disadvantages of using the protocol in a network channel for advantages we have it increases the efficiency of transmission of frames it also allows multiple frames to be sent at once and the time delay is low for sharing the packets as for disadvantages we have the tree transmission of frames in case of an error in the network channel is a very difficult work and it also requires the storing of frames on the receiver side that it receives from the center side now that we have learned everything about the go back and RQ protocol let's take a look at the much awaited working example for the same let's take a look at the problem statement in a given Network the number of frames provided is 10 with the window size assigned as 3 and for every fourth packet is lost find the total number of messages or frames sent from the sender side to the receiver site from this question we can get three main parts that are the number of frames that are given is 10. as for the window size is 3 and every fourth packet is lost let's take a look at the options option a27 option d25 option C 22 and option d29 I'll give you guys a moment to take a look at the question again now let's move on to the solution as usual we have the sender side and a receiver side and according to the question we have 10 frames dumping the frames sequentially we have frame 1 to frame 10. and then according to the question we have window size as three Now using the sliding window method we'll send the first three frames that is frame number one two and three from the sender side to the receiver side that will be like this after sending the frames we'll wait for the receiver side to send the acknowledgment and a sliding window will appear on frame number one two and three now the receiver side will send the acknowledgment for frame 1 to the sender side foreign number 4 from the sender side to the receiver side and a sliding window appear on two three and four sequence number and similarly for frame number two we'll send the acknowledgment from receiver side to the sender site and send frame number 5 from sender to the receiver side and the sliding window appears on sequence number 3 4 and 5. then again for frame number three we'll send the acknowledgment from the receiver side to the sender site and send frame number 6 from the sender to the receiver side and the sliding window appear on frame number 4 5 and 6. now let's move on for the next frame for acknowledgment that is frame number four for this Frame according to the given question every fourth frame is lost during transmission from the center side to the receiver side that means no acknowledgment will be sent from the receiver side to the sender site for frame number four in that regards or any other frame that are sent after frame number four that is frame number five and frame number six similarly frame number five and frame number six will also get discarded now let's re-transmit according to the go back in arq protocol frame number four frame number five and frame number six after re-transmission frame number four will get acknowledged by the receiver side to the sender side that means we can send next frame that is frame number seven from the sequence order and the sliding window appears on frame number five six and seven similarly let's move on to frame number five but before we do that let's count the position of fifth frame in the transmission order one two three four five six seven and eight that's correct when we count the position number for any of the frames from the beginning we use sequence not the sequence number given by the question that means fifth frame is at the position number eight from the beginning that means according to the question it will get lost during the transmission from sender to the receiver side similarly frame number six and frame number seven that was sent after fifth frame will also get discarded according to the go back in arq protocol again we will retransmit five six and seven frame number to receive a site from the sender site after re-transmission frame number five will get acknowledged by the receiver side and then we can share frame number eight from the sender to the receiver side and the positioning of the sliding window shift from 567 frame to 6 7 and 8 sequence number now let's move on to the sixth frame but according to the positioning order position of the sixth transmitted frame is number 12. that means it will get lost during transmission from sender to the receiver side and similarly frame number seven and eight will also get discarded by the receiver side and again applying go by nrq protocol we will retransmit frame number 6 7 and 8. on re-transmission frame number six will get acknowledged by the receiver side and we can share frame number nine from the sender to the receiver side and the sliding window will shift from sequence number six seven eight to seven eight and nine now let's recount the position of the next frame that is frame number seven from the beginning and that would be 16 that means frame number seven will get lost during transmission from the sender to the receiver side and similarly frame number seven eight and nine is to be re-transmitted according to the go back in arq protocol now similarly following all the previous steps we can complete this network model using go back in RQ protocol but this is a work you guys have to complete and find out the total number of packets that were transmitted from the sender to the receiver side and give your answers in the comment section and the next heading is what is selective repeat arq protocol for the first point in selective repeat IQ protocol we have is the working principle the working principle of the SRP protocol is based on sliding window protocol and it uses a buffer system for storing either at the center side or the receiver side during the data transmission let's move on to the next point for Selective repeat air queue the term arq in the protocol defines the automatic repeat request process that is designed to perform the task of sending the next frame for each of the acknowledged frame now let's move on to the next heading next heading is important points about the protocol for the first point we have is the value of n that represents the window size is same for both sides that is the value of sender size is equal to the window size of the receiver side let's take a look at the next point in case of selected repeat arq protocol as the name suggests in case the frame is not received by the receiver side or the acknowledges not received by the sender site as shown in the diagram in this case the mentioned frame is to be re-transmitted without affecting any other frame let's move on to the next point for this heading in case the frames not received by the receiver side then it will share a negative acknowledgment signal do the sender side so that it can re-transmit the damaged frame this point forms the basis of the working process involved in the SRP protocol so please take a note of this point now let's move forward with the working of the protocol we'll divide the working process of the SRP protocol in multiple steps for better understanding let's move on for the first step to begin with we have a sender site and the receiver side as usual then we have a sequence of numbers and our window size now for the Second Step let's send the First Data frame that is frame 0. next is frame one Frame 2 and frame 3. these four frames Ascend for the beginning because our window size is 4. and a sliding window appears from sequence number zero to sequence number three after the receiver side I have received the center size frames it will acknowledge the first frame that is frame 0 and saying the acknowledgment signal to the sender site after the sender site receives the first acknowledgment signal it will again share the next frame in the sequence that is frame number four and the sliding window will shift from frame 0 to 3 to 1 to 4. now similarly let's acknowledge frame number one from the receiver side to the sender side and the center side will share the next frame in the sequence that is frame number five to the receiver side and the sliding window will shift from frame 1 to 4 to sequence number 2 to 5. now let's acknowledge frame number two okay now let's assume that frame number two is lost or corrupted during the transmission in this case if we apply go back and arq protocol all the frames sent after frame number two are to be retransmitted that will be frame number two three four and five but in case of SRP protocol that is selective repeat argue protocol only the frame that is lost during transmission is to be retransmitted that means the acknowledgment signal for frame number three will be sent from the receiver side to the sender side and the sender side will then re-transmit frame number 2 to the receiver side this process of retransmitting only the loss frame is known as The Selective repeat arq protocol and similarly we will acknowledge the next frame that is frame number four and send the next frame that will be frame number six as you can see in this process of SRP protocol the sliding window or the window size clearly does not play any particular role with the completion of this slide we are done with the whole working steps involved in the SRP protocol now let's move on to the next setting in the video choose from over 300 in-demand skills and get access to 1000 plus hours of video content for free visit scale up by simply learn click on the link in the description to know more the next setting in this session is difference between selected repeat L key protocol and go back in RQ protocol let's take a look foreign for the first point we have in go back and IQ protocol it does not require a large amount of memory as it does not provide the buffer feature for the network model whereas in case of selective repeat arq protocol it requires a buffer system so the memory needed is more on both the sides that is a sender site and the receiver side now let's move on to the next point all the frames after the loss frame in go back and IQ protocol are to be re-transmitted as we already discussed in the earlier slide whereas in case of selective repeater protocol only the damaged or the loss frame is to be de-transmitted let's take a look at some other points too in go back in ague protocol too many retransmission frames are required so the efficiency of the overlr model is very low and in case of SRP protocol the re-transmission frames is less so the efficiency of the overall model is increased let's take a look at the last point for the difference the bandwidth required for go back and IQ protocol is too high due to the more retransmission frames as for SRP protocol moderate bandwidth requirement is needed with the completion of difference between SRP protocol and go back in our view protocol the user datagram protocol commonly known as UDP protocol is designed to be unreliable and connectionless in nature which applies process to process communication model for data exchange between devices and is active with the transport layer of the OSI model and is used to transfer data and information related to internet services over the network channel where process to process communication refers to the use of port numbers in the header format during the transmission of data over the network channel as for connectionless it means that the UTP format does not provide established path for the data to transfer instead it uses multiple different paths which we will look into further in the video let's move on to the next heading features of using user datagram protocol the user datagram protocol provides the network with various efficient and easy to understand Network protocol features to apply over the data that is to be transmitted where the first feature of UDP is related to the working area that is the UDP model is a transport layer protocol of the OSI model and is used to deliver best effort delivery options for the data transmission where the best delivery option refers that the protocol does not provide the sender will receive any acknowledgment from the receiver site for the data transmitted or it doesn't provide any guarantee of data transmitted to the receiver site now let's move on to the second feature of user datagram protocol the second feature represents the mode of delivery a connection that the UDP establishes for data transmission the UDP protocol as we know already establishes a connectionless path that means there is no actual virtual path for the data to be transmitted so that the each data from the UDP format uses a random path available in the network channel and reaches its destination now let's move on to the next heading that is UTP header format the UDP header format comprises of two parts first the UDP header part which is 8 bytes in size and second the data to be transmitted furthermore the header part is divided into four different parts Source Port destination Port total length and checksum where each of the parts are divided into 16 bits let's take a look at the different parts of the header format in a little detail the first one is Source port number it is a 16-bit value that is used to identify the port that is transmitting the data next is destination port number that is used to identify the port number that will be receiving the data on the receiver end next we have total length as the name suggests this value is used to specify the total length of the UDP packet including the UDP header part and the last is checksum this is a 16-bit value field and is used as an optional attribute it is left empty if there is no need or it is used in case where accuracy of the data is to be measured now let's move on to the working of the UDP protocol to begin with we have data from the sender site which is enclosed with a UDP header for communication and data in the UTP header part the next step is to hand over this data over to the IP section for encapitalization with the IP header and data with the UDP header and data part as for the last step this part is handed over to the frame section where it is transformed with the frame header and data format moving on now let's transmit the data over the network channel for the receiver and to receive it over to the receiver side first step is decoding of frame header part and data part into the IP section which contains IP header and data section again this eyepiece packet is divided into UDP header part and data part from where the message is retrieved from the data section of the UTP header format and is then received by the receiver end now let's move on to the applications of UTP protocol let's take a look at some of the features of the UDP protocol that provides applications to various Network models for the first one we have it provides flow control and error control mechanism to the network model such as tftp next it provides faster transmission of data as there is no pre-established virtual path needed so it is used for real-time Services live communication and gaming services now let's move on to the last setting for this session that is UDP versus TCP protocol we will differentiate between UDP and TCP based on some attributes that are mostly used in the network module and the first attribute is reliability for UDP protocol as we already know now it is an unreliable in nature that it doesn't provide any guarantee of data transmitted to the destination site is reached or not as for TCP it provides reliable and guaranteed data delivery to the receiver site the next attribute is acknowledgment signal the UDP protocol does not provide any acknowledgment from the receiver side to the sender site whereas in case of TCP protocol sharing the acknowledgment signal is very important if the acknowledgment signal is not shared by the receiver side to the center side the data exchange will halt let's move on to the next attribute that is connection mode as we already know now UDP is a connectionless mode of service there is no virtual path established for the data transmission to takes place whereas for TCP protocol it is a connection oriented protocol that is a virtual path is needed for the data to be transmitted over to the receiver site or the destination node the next attribute is error check system in GDP protocol basic check system is only used for error check whereas for tcv protocol it is an extensive error check service and along with error flow control mechanism included in the TCP protocol service let's take a look at today's agenda firstly we will understand what exactly the DHCP protocol is then the allocation methods in dhcb protocol next we will understand some helpful DHCP settings and lastly stepwise we will understand the operation model for DHCP let's understand the DHCP protocol the dynamic host protocol or DHCP is it protocol that is designed to assign the IP address to a device for it to access the internet this network model is based on the client server architecture and removes the process of manually assigning an IP address to the system now let's take a look at the allocation methods for the DHCP protocol the allocation method of DHCP is divided into two types the first type is the manual allocation which as the name suggests is it a signing of IP address to the system manually by the user the second method is dynamic allocation which uses a client server architecture to assign an IP address to the system now let's see some points regarding the allocation method the first type is the manual education as mentioned in this allocation type the user manually assigns CIP address to the system for accessing the internet and can be observed in this instance this is done by accessing the network configuration setting of the device and also requires other related configuration such as subnet mask preferred DNS server and default gateway let's now take a look at the dynamic allocation in this allocation method the client device receives all the relevant Network configurations from the DHCP server and the system gets configured to access the internet the provided IP address is given for a certain period which is also termed as the lease now that we somewhat understand what exactly the dynamic allocation in DHCP server is let's take a look at a small example open the start menu and type command prompt when the windows open up type IP config slash oil command as we see by this command we can take a look at the network settings for our system over here we can see that DHCP is enabled that means the configuration that has been used on the system refers to the DHCP server and on the bottom side we can take a look at the different network settings that are given along with the IP address by the DHCP server that is subnet mask default gateway and the DNS server now let's continue with the video now let's take a look at some of the notable DHCP settings the first one is known as scope as the name suggests a scope refers to a range of addresses that are available to a DHCP server for allocation of the client device next we have is lease this setting of The DHCP server is designed to prevent the holding of IP addresses by a single device this is done by assigning an expiration date to the least IP address so that the DHCP server has a minimum addresses left for the client device and lastly we have address reservation in this DHCP setting the client device requests the server to assign the same IP address to the device each time the address allocation takes place this is done by identifying the MAC address of the client device now let's take a look at the operation model for DHCP protocol the DHCP operations are performed under user datagram protocol in short UDP which is applied on two ports under UDP which are ports 67 and 68. the first phase is where the client broadcast a DHCP server message over the network to connect with the DHCP server this message basically means that it wants to connect to the internet through the DHCP server the second phase is when the DHCP server receives the DHCP message according to the message the DHCP server reserves an IP address for the client and network configuration information including subnet mask default gateway and preferred DNS server in the third phase the client responds to the DHCP servers offer through a DHCP request message requesting the offer IP address and relevant network configuration for the system then in the last phase the server acknowledges the request broadcast from the client and sends the DHCP packet to the DHCP client which is comprised of network configuration for the client device to begin practicing the commands we need to access the command prompt application using the CMD command in the start menu now let's begin with the list of commands the first command is ipconfig this command displays the system's basic IP address configuration data which includes Network information about IP addresses subnet masks and default gateway similarly we also have ipconfig slash all command which displays all the details regarding our device like Lan settings physical address of the system IP addresses subnet masks and DHCP information let's use the CLS command to clear the application window for the next one the next command is hostname which is used to access the system's hostname to verify this let's use the ipconfig slash all command to check the hostname in the information and for sure we have the same hostname let's perform the CLS command again and perform the next command the pin command is used to check the communication availability of the destination host and the user system for example use a ping command with google.com to check the server availability which gives us the following result also using the results IP address and then the pin command we can get the same result in case we just don't have the domain name we perform the CLS command again and move on to the next one the nslookup command is used to troubleshoot network connectivity and find the IP address of a domain like Google and Amazon as applied just now to receive the name and address of the domain also using the MS lookup command and then applying the server command with an IP address we can get the domain name belonging to the IP address and similarly to check the number of servers with the same domain name we can do this and we have four name servers for Google we perform the CLS command again and move on to the next one the tracered command is used to troubleshoot the routing issues of the network by displaying the routing table through which the data is transmitted to a maximum of 30 hops in the network as you can see similarly you can also try amazon.com and share your views in the comment section below now let's clear the application window and perform the next command which is the ARP command this command is applied to display the communication exchange between the IP address and the systems Mac or physical address let's move on to the next command which is the path ping command this combines the Tracer and ping commands and displays detailed information as an output for a maximum of 30 hops in the network this command takes some time to compile the full Hub details so that you can share findings in the comment section next we have the netstat command it's used to display the network connection summary of the system as shown in the demo similarly if we use the netstat hyphen n command it will give us much more details about the connection and UDP details next we have the net share command which displays the details of where the data resources for our system are shared and we can check them under the share name resources and remark column then we have the route command that allows us to access the routing tables and also allows us to make changes to them let's try the route print command and we have the interface list ipv4 routing table details with all the active routes and the IPv6 routing table moving on let's clear the window and look at the net sh command the netsh is a popular command which allows us to view and configure the network adapters in the system under the net sh command we have multiple functions so configuring settings let's try the show command and we have the following result moving on we have the task list command that lists all the currently working applications on the system with task or program ID and the memory it uses let's perform an example access Google Chrome and then perform the task list command and as expected we have the Chrome details in the list and if we close the Chrome window and again use the task list command we don't have the application active similarly we also have the task kill command which will terminate the task corresponding to the given program ID in the command window for example let's access Chrome and perform the task list command to check the program ID and then we'll use it with the task kill command and we can see that the application is terminated to check our result we can access the task list command again next on the list we have the system info command it's used to view all the information about the system from the windows version to the BIOS and booting configuration we can access all these details using the system info command and the last Network command for this session is the wmic command for getting detailed information on the ports and functions of the system like CPU details and then similarly we can check the bio settings let's start off with question one what is the OSI model explain the different layers of the OSI model OSI largely is a theoretical model uh utilized to understand networking and how data packets are created and how they are being processed by a computer this is normally used by the TCP the transmission control protocol over Internet Protocol software suite so OSI is known as the open systems interconnection model it is a reference model that describes how applications are going to interact via the computer network there are seven different layers that we need to understand they are as follows so in this diagram there are these seven different layers we start off from the bottom first is the physical layer the data link layer Network layer transport layer session layer presentation and application when such a question is asked in an interview it is not only that we identify these seven layers explaining what the OSI model is in the first place we then try to identify these seven layers and we give a brief description about each and every layer if there are any additional questions they will come after this basic question so let's start off with the physical layer this is the lowest layer of the OSI model now this is where any and every physicality of your computer comes into the picture so it could be an uh network interface card it could be an RJ45 or a CAT5 cable anything that allows data to be transmitted physically from your machine to another machine next comes the data link layer so on the data link layer as far as networking is concerned we just need to understand that data packet is encoded decoded into bits at this layer this is also the layer that deals with Mac addressing so the physical address of every network interface card which is the MAC address which is utilized to Route data package over the network this is where the MAC address resides on the data link layer the next layer is the network layer here D diagrams are transferred from one to another the function of this layer routing and logical addressing the moment we talk about routing and logical addressing IP addresses come into the picture IP version 4 IP version 6. so Network layer will deal with IP addressing and the routing of those packets then comes the transport layer this is the layer responsible for end-to-end connections that automatically signifies that this is where TCP and urep will be working TCP stands for transmission control protocol UDP for user datagram protocol TCP is a connection oriented protocol whereas UDP is a connection ledge protocol these two Protocols are utilized to establish connectivity between two machines TCP is a more reliable method of connectivity because there are a lot of packets that are sent across to verify that the data has been sent data has been received and so on so forth whereas UDP is a connection less protocol metatized just dumped without verifying whether the receiver actually receives that data or not so in a nutshell on the transport layer TCP and UDP make their appearance and this is where that functionality lies then comes the session layer this control signals between the computer it establish maintains and terminates connections between processes so in the transport layer we talked about TCP and UDP UDP being a connection less protocol where data is just transmitted without verifying whether the receiver received that data or not whereas TCP we studied is more of a reliable protocol thus there are different packets signals that will be sent across to verify that data has been transmitted it has been received properly and then the next uh segment of that data is being said so those control signals are established using the session layer so the three-way handshake of TCP the acknowledgment packets and those kind of packets will be taken taken care of on the session layer of the OSI model then comes the presentation layer the presentation layer is responsible to translate data into the application layer format so the formatting right mine or encoding that is being utilized the utf-8 character set that we utilize for presentation encryption mechanisms all of these work on the presentation layer and finally comes the application layer where the application itself uses a particular protocol so that the other machine on the receiving end the application on that machine would be able to understand what the communication was about right so in a nutshell if I start from up top the application layer will deal with any of the data that the application is generating so maybe an user input you're logging in you're typing a username password all that data will be constructed let's say to an HTTP or https format that's where your application layer comes into picture then the formatting of which into utf-8 and the encryption of which would be done at the presentation layer then this transport layer and the session layer would kick in to establish a TCP session do the three-way handshake establish that connectivity IP addressing would be done on the network layer Mac addressing would be done on the data link layer and when everything is ready on the physical layer the packet will be sent out at the receiving end the packet will be received on the physical layer and then all these layers will be reversed and finally at the application layer the data would be presented to the application who would then execute it and showcase it on the screen of the recipient so this is the way you want to explain this question you want to be very concise precise about what you're explaining you don't want to go into two hypothetical scenarios you don't want to delete earlier with the layers you just want to give the basic functionality you want to demonstrate that you understand what the OSI layer is how the computer functions and you want to move on from there if the interviewer has any further follow-up questions they will ask those specific questions so that's question one moving on to the question two question two is Define unicasting multicasting and broadcasting now this is a question which can be very lengthy but again most of your interview questions are designed that way it's basically to understand how much conceptually you are aware about these Technologies so you have to be very concise don't go uh rattling about technology too much but in a concise manner just try to explain what these things is so when data is being transmitted over a network it can be transmitted either in one of these particular manners it can either be a unicast multicast or a broadcast so what is unicost unicast is when a message is sent from a single user to a single ratio so one to one right so uh one machine talking to another machine and nobody else so also known as point-to-point Communications 1.1 the point if you have to send information to multiple receivers then you will have to send it using multicast right so this is where your multicast networking comes into the picture so in our case uh let's assume it's a network where there are there's a Class C Network approximately 255 odd machines and Within These there are two machines that want to talk to each other if they want to talk between each other it would be a point to point communication where they will utilize unicast where only these two machines will have visibility of that conversation and the other machines will not even realize that this conversation is taking place if one machine wants to talk to multiple machines then the multicast comes into the picture as the name suggests in this mode of communication data is sent from one or more or more sources to multiple destinations multicast uses the internet group management protocol also known as the igmp protocol to identify groups so under this igmp protocol various groups are created where machines are subscribed to those particular groups and whenever a message needs to be sent through those groups it will be identified by the igmp protocol and then that particular message will be sent to those multiple machines that are members of those particular groups and then comes the broadcast the third method is known as the broadcast as it says it is going to broadcast to all so this is one to all that is communication between a single user and it is going to be sent to all the machines in that particular Network right so the three ways unicast is one to one multicast is one to many and broadcast is one to all then question number three what is DNS DNS stands for domain name system it is like the internet's phone book that is responsible for mapping the domain name into its corresponding IP address and let me give you an example over here whenever we go and open up let's say a browser a Google Chrome browser we type in www.google.com and then we press enter and magically Google comes in front of us the website rather now how does the computer know who Google is because as far as we are concerned humans understand Google and words like that computers don't computers deal with binary zeros and ones right and as far as Internet is concerned they will only deal with IP addresses and Mac addresses so how does a computer know how to find google.com and where is it located so the moment we type in in the browser window in the address bar google.com and press enter a DNS query is generated automatically by the browser where a packet is sent to our DNS servers asking what the IP address is so in short DNS resolves domain names to their corresponding IP addresses there is a DNS server which will have this index a database of all the domains associated with their IP addresses if one particular DNS server does not have that information that you're looking for it may query another DNS server who may have that particular response so the first thing is when you type in domain name it gets resolved with the DNS it identifies the IP address corresponding to that particular domain name and thus allows the computer to route that packet to the particular server where that domain name resides so in this scenario if you look at the screen on the local PC you have typed in cybersecurity.com there's a DNS resolution that a query that goes to the DNS server what is the IP of cybersecurity.com the DNS server looks it up in its particular database if it has the corresponding IP address it will then respond back the IP address is 172.17.252.1 after which the packet is sent off to cybersecurity.com moving on to question number four what is a firewall now this is a very good question and normally a very basic answer that I've ever heard is that a firewall is a hardware and a software firewall but that's the functionality of a firewall that is what how you can install a firewall but there are different types of firewalls and there is a specific functionality that the firewall is created for right so firewall is either a hardware or software but its responsibility is for blocking either incoming or outgoing traffic from the internet to your computer they secure a network so essentially the firewall will allow a connection to happen or this allow a connection to happen it won't go beyond that that's the basic functionality of a firewall okay so based on the configurations that you have done based on the rules that you have created on the firewall it will then based on those rules identify whether some traffic is allowed in that Network or some traffic is to be blocked from entering that Network so as the screen shows the firewall rules will analyze whether the traffic is good if yes it will allow if the traffic is bad it will block the traffic and not allow that connection from happening in the first place now there are a few common types of firewalls that also need to be included in the answer to this question and the first one is a packet filtering firewall these are the most common types that you will come across which analyze packets and less than pass through only if they match an established security rule set now here people do get confused when we say that we analyze packets people think that these firewalls will analyze the contents of that packet which is not correct when the definition for a packet filtering firewall says that these firewalls analyze packets it means that they are only analyzing the source and destination IP addresses port numbers and the protocols that are mentioned in those packets these firewalls do not have the capability of deep packet inspection or a DPI as it is known if that capability comes into the picture you're basically looking at an intrusion detection system or intrusion prevention system in today's world called as a next-gen firewall okay so a packet filtering firewall essentially will only analyze data package for its source and destination IP addresses port numbers and the protocol that is being utilized it will then map that information to the rules that are there on the firewall and based on those rules it will either allow that a connection to happen or disallow that connection from happening the second type of is a proxy firewall these firewalls filter Network traffic at the application Level So when you say application Level they work at the layer 7 of The OSI model package filtering firewalls since we have mentioned that did work on IP addressing and port numbers will work on the network layer of the OSI model also on the transporter because you also look at protocols proxy firewalls will work at layer 7 which is the application layer of the OSI model and will deal with application Level protocols such as HTTP https FTP SMTP and so on so forth and the third one is a stateful multi-layer inspection firewall these filter packets are the network transport and application layers so they basically do the job of the first and the second type of firewalls the packets are compared to loan trusted packets but now the first question is if there is a stateful multi-layer inspection firewall why do we have type 1 and type 2 firewalls like packet filtering and proxy firewalls that is because that is how the firewalls have evolved we started off with a packet filtering then we added functionality to it and so on so forth so if a question comes what is a firewall you start off with the option saying it is a hardware or software this is the responsibility the functionality of a firewall is to allow good traffic and disallow bad traffic based on the rules that have been configured on the firewall and then you've got basically three types of firewalls packet filtering proxy and stateful multi layer and just include a brief description of each of these firewalls if getting your learning started is half the battle what if you could do that for free visit scale up by simply learn click on the link in the description to know more then moving on to question number five what is a VPN VPN is also called a virtual private Network it is a connection between a VPN server and a VPN client so it basically creates a encrypted tunnel between the client and the VPN server which is then utilized to secure the connections that you're making with the internet so as you can see in the diagram the user has a VPN client installed on their machine the VPN client then creates an encrypted tunnel to the VPN server and through this tunnel encrypted data is transmitted which can then be processed by the VPN server uh sent to the internet information can receive can be received backed by the VPN server the VPN server will encrypt that data back and send it back to the user so if there's a man in the middle attack that is happening or a hacker trying to eavesdrop on the communication mechanism they will not be able to do so because of the encrypted it is very difficult to decrypt this or hack through this encrypted tunnel it it is possible but it is very difficult to achieve that moving on to question number six what are the advantages of distributed processing now before we go into advantages of distributed processing we first have to understand what is distributed processing so it is a term which describes various computer systems that use more than one processor to run an application here multiple computers across different locations share the same processor the advantages of Distributing processes are as follows but before we go into the advantages distributed computing is basically where multiple machines will pool their resources together to run a singular application so an application that has multiple resources and you can scale up and scale down as and when required the advantages are that it can be very very useful in data recovery for example read where your striping data on various hard disks it is reliable it is cheaper lower cost can be achieved and it is easy to expand because of the scalability factor that we just talked about if there is loss of data in one computer it can then be recovered by another interconnected computer and one of the examples would be blockchain in today's world right what is blockchain that this data is created live and stored on a connection of computer so if one of the computers goes offline the other computers in that network will still have that data and there the blockchain will still function without any issues the second point a glitch in one machine does not affect the processing as there will be multiple other machines like we discussed in the blockchain several cost effective mini computers are used instead of costly or Mainframe machine so instead of having a server Bank I can have multiple machines connect interconnected together and they can function in that particular blockchain or for that particular distributed processing mechanism depending on the amount of data processing more computers can be attached to the network thus you can increase the number of computers that can be a part of that blockchain or you can reduce them as and when necessary moving on to question number seven what is tcpip tcpip or transmission control protocol over Internet Protocol is a set of communication protocols that are used to interconnect networking devices on the internet this protocol defines how data should be transmitted over the Internet by providing end-to-end Communications so essentially if you want networking to be established on your machine you will need TCP without TCP there will be no work groups there will be no domains basically your interconnectivity will go for a toss TCP is a software that once installed on your machine will then interact with the hardware which is your network interface cards and then your switches wires cables and all those through protocols that have been already pre-configured in it So within the tcpip suite of softwares you will have all the protocols all the functionality of the OSI layer and each and every protocol that works on each and every layer will be predefined and pre-configured to work in a particular manner the Internet Protocol is all about routing each individual packet to make sure it reaches its destination so with the TCP you are talking about the protocols that will allow you to format the data and generate it so that you can communicate it over the network the IP will then deal with the routing of those packets so that the packet can be routed to the correct computer and be received by the recipient so the TCP model is the compressed version of The OSI the seven layers will get converted into four layers the network access layer internet layer transport layer and application layer going on to question 8 what do you mean by ipconfig and ifconfig both of these are commands the first one on a Windows machine the second one on a Linux machine so ipconfig is known as the Internet Protocol configuration this is a command that is used on the command line interface of Microsoft Windows to view all the adapters and the configuration of each and every adapters for their network interfaces so as you can see on the right hand side in the command prompt screen if once you type in the IP config command on the C prompt and press enter it will give you a list of all the adapters that are there so you can see wireless LAN adapter local area connection the media is disconnected it doesn't exist at the bottom you will see the Wi-Fi connection wireless LAN adapter and it can give you the IP version 6 IP address IP version 4 address the subnet mask and the default gateway so this is the configuration that allows the machine to know on what network it is on what is the default gateway for communicating to the internet what is the subnet mask so how many computers may exist in that particular Network and what is the IP address of that specific computer so that it can communicate across the network as well ifconfig is the same thing on the Linux Mac or Unix operating system so the command will also give you the list of interfaces and the configuration of each and every interface it is used to configure control the tcpip network interface parameters from the command line interface it allows you to see the IP address of these network interfaces so here you can see uh the wlp 19s the IP address being 192 168 43.215 subnet Mass being 255.255.255.0 with the broadcast being 192.168 43.255. question 9. what is the difference between a domain and a work group this can be a very interesting question and can be a very lengthy question at the same time a work group is nothing but a decentralized network where you have interconnected multiple machines together and each machine acts in its own individual capacity things of itself as a server right so a decentralized network you every user manages the resources individually on their PC so local users on their own PCS managing the network shares what can be shared from that particular machine what data should be shared should not be shared to whom it can be shared with and so on so forth it is good if you got a small Network a few machines all together uh and you want them to interact with minimal management effort right so each computer each user will decide what they want to allow other users to see on that particular Network and all of them would be connected over a land a local area network either a wireless or a wired one so if you look at your home Wi-Fi right now that is one of the best examples of having a work group the domain on the other hand is a centralized Network model so in a corporate environment whenever you go there and you've got a domain-based username and password which when entered onto a particular machine gives you access to the entire network or whatever applications and whatever resources have been allocated to you that is where the domain comes in so it it also uses a single sign on mechanism for all the resources that are made that are to be made Available to You whereas in a work group your local user only meant for that particular computer right so coming back to the domain it is an administrator who is going to manage the entire domain and all of the resources connected to the domain the resources could be switches routers servers data stores applications web servers Mail Exchange servers and so on so forth so all of these are administered by an administrator through the domain it is the most reliable and Optimum solution for a large Network where multiple users are going to interconnect and share that data amongst each other right the computer can be connected to any network that means you can be on the internet and through the internet using a VPN you can connect to your corporate Network authenticated and get access to whatever resources you are allowed to access whereas in a work group you have to be a part of that Network to access that particular network if you change your location you go and connect to another Wi-Fi you will lose access to your previous Wi-Fi then the last question for the networking section what is data encapsulation in networking data encapsulation refers to the process of adding headers and trailers to the data the data link layer binds each packet into a frame that contains the hardware address of the source and the destination computer so in this example when you're talking about data encapsulation we have talked about how data that has been created by the application layer will have a header and a trailer that will give the various informations of where that data needs to be sent so the hardware address which is the MAC address comes into the picture and gets added to the header and the IP addresses port numbers and all of those things would then be added to this uh Traders as well so that the data can be then routed to the intended recipient of that particular communication so with this we have come to the end of this session on the networking full course I hope this session was informative and interesting if you have any queries regarding any of the topics covered in this session or if you require the resources like PPT code documents or anything then please let us know in the comment section below and our team of experts will be happier to resolve all your queries at the earliest until next time thank you stay safe and keep learning thank you hi there if you like this video subscribe to the simply learn YouTube channel and click here to watch similar videos turn it up and get certified click here