Transcript for:
Comprehensive Guide to Network Security

welcome to the ultimate network security engineering full course in this full course we are delving into the realm of network security engineering like never before name a strong foundation with networking Basics suitable for beginners to understanding about ethernet and dissecting Network topologies we'll Journey Through the essential TCP IP and OSI models while understanding the differences between ipv4 and IPv6 but that's not all will also explore the wonders of Wireshark tackle subnetting and unravel the concept of parity check get ready for a knowledge packed Adventure that will Empower you with the skills and insights needed for a successful journey in the world of network security engineering so let's start with the first topic but before we begin make sure to subscribe to our Channel and hit the Bell icon to never miss an update from Simply learn so if you want to become a cyber expert look no further introducing our post Gadget program in cyber security your gateway to mastering comprehensive strategies for safeguarding infrastructure and fortifying data Dell into risk analysis mitigation techniques and compliance practices that are Paramount in today's digital landscape from foundational principles to Advanced methodologies this program offers an array of industry-leading cyber security certification courses that form the backbone of your journey equip yourself with expertise needed to thrive in every evolving realm of cyber security enroll now and pave the way for a secure digital future an introduction to network security 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 with 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 this aim sets equal to the confidentiality 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 so 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 equipping 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 is becoming increasingly difficult in today's hyper-connected environment as more corporate applications migrate to both public and private clouds 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 you 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 institutions next comes authorization this process decides the level of access provided to the recently authenticated user for example 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 freezes a threat environment that is always changing and attackers that are always trying to find an exploit 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 store 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're 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 and 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 circuits poor app player 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 you 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 fireball is a type of network security device that keeps track of incoming and outgoing Network traffic and it decides which traffic to allow or deny 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 intrusion 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 inclusion 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 on some kind of similar pattern is noted by the ID administrator can detect some kind of attack the similar attacks can be stopped and the security can be further enhanced another you have 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 are 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 posture that considers shooting 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 drugs 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 dangers may be identified and dealt with before they become expensive disasters the third benefit is ilki's 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 must significantly minimize violations and the amount of downtime required to fix the breach by implementing various cyber security measures such as enhanced firewalls virus 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 place a premium on maintaining brand loyalty through a strong cyber security stance then 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 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 the local area network also known as plan 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 group of virtualization has also sped up the creation of virtual lands which let Network managers divide and logically organized 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 IIT support and administration still there might be segregated to operate separately the benefits of a land 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 area 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 is saying 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 Dot 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 LAN every devices is a part of a 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 these IP addresses serve only half the purpose hence 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 the role of the delegation and commands in a particular Network let's learn more about switches in detail a network switch joins 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 be 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 the index of PCS access points automated equipment and some iot devices via wired connections such as card entry systems The Limited 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 the 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 transfers data packets across computer networks router checks and data packets destination IP address and utilizes headers and forwarding tables to determine the best path to transport the packet consider the router to be an air traffic controller and data factors should be airplanes flying to various airports or networks in this case each package like each check has a unique destination and must be steer 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 lost or experiencing severe disruptions a router employs an internal routing table which is a collection of Pathways to multiple Network destinations to properly direct packets let's cancel 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 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 which help determine 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 two flags do 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 the 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 for any of the 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 and so router receives 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 correct destination to send the external leadership data to but let's say a device on the external network or a wide area network wants to communicate directly with a 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 or denies 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 rule set 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 DMC sub network with only those devices added to it that's required under external information to reach them on all 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 it's all you really need to know for now about the basics of networking 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 any 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 per second 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 Switched 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 USM module also known as data link layer 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 with 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 as 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 then 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 krishnar 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 setups 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 Link topology in the case of a node crash the whole system is affected and is non-accessible due to the direct connection of each node the transfer of data is low due to the Token passing method in the network difficulty in the trouble shorting fault in the connection leads to the crash of the whole network now let's talk about star topology 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 nodes 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 crash 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 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 osm 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 DC VIP 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 TCP 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 forward it 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 TCP 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 tcpip 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 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 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 USM 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 delays 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 layer so that it can be passed on to the session layer the next layer in the osm 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 the 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 with 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 2 bit 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 tab 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 lab 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 wired medium or wireless media introduction to network protocol a network protocol is like a set of rules that govern how devices in a network communicate with each other these rules are like instructions that specify how data should be sent received and understood by the devices Network Protocols are formalized requirements and plans that consist of rules and procedures that describe how devices should interact with each other over a network they provide a communication system to exchange information using various physical means such as cables or wireless connections just like humans follow certain protocols when they interact with each other network protocols Define a specific steps and guidelines for devices to follow these rules ensure that information is sent and received correctly and that all devices is involved understand each other in essence natural Protocols are a way for devices to speak the same language and follow a common set of guidelines so that they can successfully share information and work together effectively now let's understand the need of network protocols all right so let me explain this to you in simple terms Network Protocols are like guidelines that devices follow when they communicate with each other over a network these Protocols are needed for several reasons firstly Network protocols ensure that devices understand each other imagine if you and your friend were speaking different languages and had no way to understand each other communication would be impossible similarly devices from different manufacturers and with different functions need a Common Language or protocol to understand each other's signals and data secondly Network protocols ensure that data is transmitted reliably when you send a message or a browser a website you want to make sure that the information reaches its destination accurately and without errors Network protocols help in breaking down data into smaller packets sending them across the network and reassembling them correctly at the receiving end thirdly Network protocols provide security they include measures to protect data from unauthorized access and ensure that sensitive information remains confidential this is particularly important when you make online transactions or share personal information over the Internet lastly Network protocols allow for interoperability this means that devices from different manufacturers and with different functions can work together seamlessly for example your computer can connect to a printer and your smartphone can access a Wi-Fi network because they follow the same protocols so these were some of the needs of network protocols now before understanding the types of network protocols we must to understand about ethernet so ethernet is a type of network protocol that helps devices connect and communicate with each other in a local area network Lan it is like a highway that allows data to travel between devices such as computers printers and routers ethernet uses a set of rules and procedures to transmit data in the form of packets these packets are like small packages of information that are sent from one device to another ethernet ensures that these packets are delivered to the right destination and in the correct order think of ethernet as the road system that connects all the devices in our Network it ensures that data can flow smoothly between devices enabling them to share information and work together efficiently now let's have a look at the types of network protocols here we will cover some of the types of network protocols we'll start with the first one which is TCP that is transmission control protocol TCP is a network protocol that ensures reliable and order delivery of data between devices it breaks down data into smaller packets sends them across the network and ensures that they are reassembled correctly at the receiving end TCP also handles error detection and re-transmission if any packets are lost or corrupted during transmission so this was about TCP or transmission control protocol now second is IP that is Internet Protocol IP is another Network protocol that handles the addressing and routing of packets across the internet it assigns unique IB addresses to devices and determines how data is sent from The Source device to the destination device IP ensures that the data packets reach the right destination by routing them through various network devices like routers third is UDP or user datagram protocol UDP is a network protocol that provides a faster but less reliable method of data transmission compared to TCP it does not establish a connection or guarantee packet delivery or order UDP is commonly used for time sensitive applications like video streaming or online gaming where a small amount of data loss is acceptable next is pop that is post office protocol pop is a network protocol used for retrieving emails from a mail server to a client device it allows users to download emails from the server onto their device and manage them locally pop is typically used by email clients like Outlook or Thunderbird next we have is SMTP or simple mail transfer protocol SMTP is a network protocol used for sending emails from a client device to a mail server it handles the transmission of email messages and ensure that they are delivered to the appropriate recipients mail server SMTP is responsible for the reliable transfer of email across different mail Reserve so this was about simple made transfer protocol now let's understand the sixth one which is file transfer protocol or FTP FTP is a network protocol used for transferring files between devices over a network it provides a standard method for uploading and downloading files to and from a remote server FTP allows users to navigate directories transfer files and manage file permissions now coming to the next which is hypertext transfer protocol secure that is https HTTP is a secure version of HTTP that provides encryption and authentication it ensures that the data transmitted between a web browser and a web server is encrypted and protected from unauthorized access https is commonly used for secure online transactions sensitive data transfers and protecting users privacy so these were some of the types of network protocols so basically Network protocols play a crucial role in enabling communication and data transfer across various computer networks we have explored several types of network protocols each serving specific purpose and operating at different layers of networking model so if you want to become a cyber expert look no further introducing our post-gadget program in cyber security your gateway to mastering comprehensive strategies for safeguarding infrastructure and fortifying data delve into risk analysis mitigation techniques and compliance practices that are Paramount in today's digital landscape from foundational principles to Advanced methodologies this program offers an array of industry-leading cyber security certification courses that form the backbone of your journey equip yourself with expertise needed to thrive in ever evolving realm of cyber security enroll now and pave the way for a secure digital future 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 which was 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 four 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 IR reference we can identify ipv4 addresses from IPv6 addresses now let's move on to the next topic that is IP classes 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 e 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 moderate 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 one one and zero 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 we have 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 and 0. with network ID range is 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 ipv version is designed of four hexadecimal digits and eight 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 to be stateful that uses DHCP server for network settings and stateless that applies Auto configuration settings ypv6 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 ibv6 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 bearers for IPv6 addresses are based on alphanumeric type data with eight Fields each separated by a colon 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 moving on we have the number of R gases in each IP in case of ipv4 the total number of addresses are nearly 4 billion addresses whereas in case of ipe 6 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 ipb4 version addresses do not provide any security function for the network whereas in case of iv6 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 is 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 let's take a look at Network sniffing to access the network related information between devices to gain profit or use the Hacked data for illegal purpose is known as Network sniffing this is a process where a hacker only measures programmer spy into the network devices of our system they can access different websites that we visit often or see our Network habits let's take a look at different tools that are suitable for sniffing purpose Network sniffing tools are softwares that are available on the internet that can be used to sniff into the network let's take a look at some of the famous Network Tools this is a networking sniffing tool which has specialization in intelligent analysis for Network packets next is Wireshark this software tool is best to look into protocol related data packets that are often transmitted over the network and lastly we have solar wind Network packet sniffer where the performance of this sniffing tool is best where the Performance Management is to be looked into let's take a look at the Wireshark sniffing tool this is an open source Network sniffing software which is specifically designed to attack data packets during a transmission over the network this type of software uses different color combinations to represent different packets and protocols let's take a look at some of the uses for the sniffing software the first use is it is used to analyze Network packets whereas it can also be used to troubleshoot different network issues which are often used by different Engineers to test whether the software or network device is susceptible to an attack and lastly it is also used to check malicious and hacking possibilities on the network now that we are completed with the briefing for the software that is known as Wireshark let's take a look at the actual demo how exactly Network sniffing is done you can directly access the Wireshark software website where you can find the download option and download the most suitable version for your laptop or computer device after downloading the software when you install it you will get something like this as we can see these connections are the connections that are connected to my laptop right now and the difference in the graph that we can see over here represent the traffic on the network that is present too much better what exactly is going on the network we can access one of them let's access the Wi-Fi network on my laptop after accessing the network we can see some packet settings like this these represents the packet transaction that has been made on my network through the internet and this is how a hacker or a cyber criminal knows how exactly we use a network services this part of the Wireshark represents different detail information about the transaction that has been made and the last section represents some raw data or Garbage data but how exactly a hacker use all this jumble data and hack into a system well to clarify this is an option that can be used that is known as diff display filter on the Wireshark software if you want to search for a specific protocol for example TCP we can write TCP in the search filter and search and now as we can see we only get the protocols that are related to TCP this is how we can differentiate different protocols and access some of them to gain knowledge about what exactly is going on in the network let's try accessing some other protocol now for example DNS and as we can see only the protocol and the data packet that is related to DNS protocol is visible to us to further enhance the display filter let's try accessing our different page on the web browser for example simplylearn.com when we access a simply learn website we can see the professional courses that are available but let's take a look at the changes that has been made on the Wireshark to know this let's write TCP and a keyword included contains and one more thing to include over Eis during the display filter if you write something that is related to the software it will represent in a green color like this but if you write some error related keywords like this it will represent in the red let's continue with the search setting including the contains keyword and writing simply learn and entering now as we can see these two related data packets represent the simply learn website that we access just now where the source destination IP address represent my system address whereas the destination that is 13.224.21.74 represent the simply learns IP address let's take a look and in the garbage area or the raw data we can take a look simply learn website to see some more details regarding the same you can access the transport layer security and the transmission control protocol where we can see the source Port the destination Port which is always 443. as well as the flag and the timestamp for the same this is how hackers get the data about a network settings but if we want to search for more data related to Simply learn website that we visited just now they send another filter that we can use for example using IP Dot addr space equal equal and writing the IP address for the website simply learn that is 30.224 .21.74 and when we press enter we get all the related data for the simply learn website and this is how we can see the related data to much further enhance our display settings let's try in another example access your internet browser and access some other website for example dot for example the State University and access the alawat State University and some other are in it for example the university State PDF let's see the changes in our Wireshark settings and try using http when we write this we get the data that is related to the HTTP but what is the use for the same when you access this and right click on the same and choose the option follow and HTTP stream and over here we can take a look at the host that is the website that we just visited now imagine if we were a hacker and we knew all this we can access any website that a user visited and we can hack into his system through the website guys but the point that has to be noted over ERS if we use the network sniffing tool why shark or some other tool that is available on the internet for research purpose or experimental use that's fine but we shouldn't use all these softwares for any malicious activity because that is illegal now some of the two options that we can see are the Red Box this action is used if you want to stop the traffic connection that means if we press this option and clear this and press enter this shows that the network settings has stopped receiving any traffic that is available on the network but if we want to access them again you can choose this Bluefin option continue without saving and the software against start recording the websites or the data packets that are available on the network now let's take a look at an example as we all know we often visit different websites and there are some cases we often see when the Chrome represent a non-secure option that represents that the website is unprotected against network attack for example we can access our experimental website this is a website that allows us to access the non-secure part of a website if we write for username as admin1213 and for password as simply learn and login as this is an experimental website it says it's sorry and the login has failed let's see the changes in a Wireshark software now as we already did earlier if we want to access a specific website we should write TCP contains and the keyword of the website that was Edmund through this we can see this was the website that we visited just now but if we want to access the actual important data that was the password that we typed we can use this option and over here we can see the simply learn which was encrypted earlier in the website this is how a hacker or a cyber criminal use different sniffing softwares and gain data about different users and with this we have reached the end of the session let's take a look at the agenda for today's topic in the beginning we will learn about what is subnetting then continue with what our class addresses and subnet mask characteristics of subnetting then see some of the benefits of using subnetting process and lastly the drawbacks of using submitting let's begin the first heading is what is subnetting the process of subnetting is to divide the network into smaller Network paths this allows the system to have better connectivity in the system it also increases the security measures for the network against hacking attempts and also maintains an efficient flow of network traffic the smaller divided units of the network are known as sub Networks taking an example of an IP address with Slash 24 representing the subnet mask can be divided into two sub-networks or slash 25 subnet mask which can further be divided into smaller sub Networks now that we understand what is subnetting let's move on to class addresses and subnet mask firstly let's begin with class addresses to better understand the submitting process we need some information regarding different classes used in IP address where the first class is Class A with a range of 0 to 127 Network width AS Slash 8. then we have class P with a range of 120a to 191 with network bits as 16. and lastly we have class C with network range of 192 to 223 with network bits as 24. the network is representing each class are very important when making subnets of a particular IP address let's see how they do so for this we'll be representing each class in binary format for class A we have 1 for 8 Bits for class B 16 bits and Class C 24 bits moving on we will see what exactly is the subnet mask to better Define the sub networks in the system we require the use of a subnet mask that is the subnet mask is a way to differentiate between the portion of an IP address that represents the network address ID and the host network ID in this let's see the default subnet mask for each of the class for class A we have 255.0.0.0 for class B we have 255.255.0.0 whereas for Class C we have 255.255.255.0 to better understand this let's take a look at the classes individually the network ID part is the one that represents the binary digit 1 whereas host ID represents binary digit 0. that means for class A we have 8 bit size network ID and the remaining bits as host ID by looking at the host ID we can see that the network addresses that are available for the host is the largest in the class A whereas for class pvm 16 bits for network ID and the remaining for host ID where we can see the remain part for the host ID is lesser than Class A that means Class B can assign Network IDs for a medium level company and lastly for Class C we have 24 bits as network ID and the remaining for host ID from this we can see that the host ID used for Class C is the lowest that means only smaller division companies can use Class C moving on let's take a look at the characteristics of the subnetting process first is the network ID to 3 present the first IP address in each subnet block then we have broadcast ID which indicates the last IP address of the sub Network block moving on behalf first host ID which is the immediate first IP address after the network ID then we have last host ID as the name suggests it defines the IP address before the broadcast ID continuing we have next network ID this defines a network ID of the next subnet block then we have the total number of IP addresses in the sub Network block and lastly we have subnet mask or cider which represents the network ID and the host ID part in an IP address to better understand all the attributes of the subnetting let's take a look at an example in this example we are assuming an IP address 192. 168.0.x with a subnet mask of 24. for this IP address we have divided it into four parts that represent slash 25 27 27 and last part AS Slash 26. now let's find out the details that means the attributes for the sub Network slash 25 the first attribute is the number of IP addresses going by the table we have 0 to 256 addresses in a single block but in this slash 25 represent only 0 to 128 that means the total number of addresses in slash 25 subnet block is 128. moving on we'll find out subnet mask or citer that is the default subnet mask of Class C which I have taken reference from the subnet table which was explained in the earlier slide such as 255.255.255.128 then we have the network ID which represents the top most Network address in the sub Network Block in our case it is 192.168.0.0 then we have broadcast ID which is the last IP address in any sub Network Block in our case it is 192.168.0.127 moving on the network ID and the broadcast ID addresses cannot be assigned to any network device in the network because the network ID is used to identify the sub Network Block in a network along with the broadcast ID which is used to communicate with any of the hosts that is connected to the sub Network block that also means that the total number of usable network ID addresses in a network block is total number of IP addresses minus 2 that represents network ID and broadcast ID that would be 128 minus 2 and we get the value of 126 which represents the total number of IP addresses that are usable moving on the next attribute is first host ID that means the first ID after the network ID which is 192.168.0.1 then we have the last host ID which is 192.168.0.126 which is just before the broadcast ID and lastly the next network ID which is 192.168.0.128 now that we are clear about all the characteristics of our sub Network how what are practice from for everyone to find all the characteristics for the sub Network block slash 27 subnet mask you can give your answers in the comment section let's move on to the benefits of using subnetting where the first benefit is enhanced Network efficiency through the use of applications of subnetting we can share data through not only a specific portion of the network model rather than broadcasting to the whole network causing unnecessary traffic in the channel as shown in the example over here we see four different hosts and if we want to share specific data to only two of the host we can subnet them into specific parts through this the router will only send data to the specific portion of a sub Network rather than broadcasting to the whole network channel this will prevent Network traffic yeah moving on the other benefit of using subnetting process is network security subtracting also provides protection to an extent against any hacking attempts made on the network model due to the complexity of the sub networks as presented in the example during the hacking attempt if we can identify how the virus attacks the network model we can prevent it from attacking all the subnetworks by compromising a single or two of them and preventing the remaining subnetworks let's move on to the drawbacks of using subnetting process the very first drawback of using the subnetting process is it makes the network model much more complex which in turns affects the maintenance and efficiency then we have the unused IP addresses which are left over from applying the network model in a sub Network process and lastly we have the low efficiency use of Hardware devices if the hardware devices such as router or switches used are of low efficiency the performance of the sub Network water 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 node a 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 node 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 the route 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 is sure to be established due to the predestined path circuit switching is preferred for long and continuous 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 foreign 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 in between the sender and the destination node in the message this technique integrates the destination address into the data transmitted 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 node 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 pocket 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 path 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 loss of data packets during the transmission in case of overloading or Corruption of data 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 erq 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 site 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 BN 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 0 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 0122 to 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 see the acknowledgment from the receiver side this 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 what is peritable check the parity bit is a data check bit 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 they are 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 bits 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 with 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 site and also in some cases it is used to correct the change there are two types of parity 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 1 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 disable 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 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 side by the sender side after the data has reached the receiver side there are a few cases that may arise in the data where each one is the database received to transmission has no errors that is the data received is correct after applying the parity bit 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 even 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 site is four 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 we will look into some of the most popular commands applied by users to handle network issues and save precious time so stay tuned but before we begin if you love watching Tech videos subscribe to our Channel and hit the Bell icon to never miss an update from us 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 hop 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 for 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 so if you want to become a cyber expert look no further introducing our post Gadget program in cyber security your gateway to mastering comprehensive strategies for safeguarding infrastructure and fortifying data Dell into risk analysis mitigation techniques and compliance practices that are Paramount in today's digital landscape from foundational principles to Advanced methodologies this program offers an array of industry-leading cyber security certification courses that form the backbone of your journey equip yourself with expertise needed to thrive in ever evolving realm of cyber security enroll now and pave the way for a secure digital future the distance algorithm was invented by edscar w dextra this regarded them 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 dextra's 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 a 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 node 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 text trans 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 only 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 note 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 on 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 will be noted is that we have updated the previous node as a for both the nodes V 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 only 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 the 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 come 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 reduce 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 dixras 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 path that the data packet can take to reach its destination node from initial node where P 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 the 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 intervals 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 will 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 with the Hop to eight 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 there is 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 note 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 the 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 no date 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 airq 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 destabilishing 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 balance 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 feed 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 fcsu 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 flat 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 free 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 note for the S frame s the first two bits of the control field is 1 and 0. which act 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 parts 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 side now step 3 step 3 begins at the receiver side 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 one 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 obtain 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 wants 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 bits or one redundant bit in case of Parental check method only one redundant bit is added to the original data now let's move on to the next key point that is participants the parity weight check method is a method to add binary depicts 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 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 side by the sender side after the data has reached the receiver side there are a few cases that may arise in the data where each one is the data bit 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 1. 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 humming 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 a 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 other 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 Hamming code that is parity pills the parity bit is a method to append binary bits to secure that the total number of counts of 1 in the original data is either even number or an odd number let's take a look why do we exactly use parity builds 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 1 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 n 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 solve an example to better clarify all the concepts let's move on the given 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 one 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 archers 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 0 now let's move on for P4 that would be 4 D5 D6 and D7 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 obtained 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 read 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 setting 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 the acknowledgment 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 site let's send the last frame that is frame 2. now we have to wait for the receiver side 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 site 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 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 zero one two two to 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 will 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 B25 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 numbering the frames sequentially we have frame 1 to frame 10. and then according to the question we have window size S3 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 the 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 a sliding window appears on sequence number 3 4 and 5. then again for frame number three we will 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 and 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 frame is 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 site 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 side 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 in arq protocol all the frames sent after frame number two are to be re-transmitted that will be frame number 2 3 4 and 5. 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 re-transmitting 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 skill 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 erq protocol and go back in RQ protocol let's take a look for the first point we have and 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 in IQ protocol are to be re-transmitted as we already discussed in the earlier slide whereas in case of selective repeat RQ protocol only the damage 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 re-transmission frames are required so the efficiency of the overlr model is very low and in case of SRP protocol the re-transmission the frames is less so the efficiency of the overall model is increased 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 Q 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 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 or 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 re 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 does not 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 site 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 vertices 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 DHCP 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 the 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 off 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 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 Port 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 server's 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 you have the same hostname let's perform the CLS command again and perform the next command the Ping 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 has applied just now to receive the name and address of the domain also using the nslookup 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 hop 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 a 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 for 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 up 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 datagrams are transferred from one to another the function of this layer on 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 connectionless protocol metatizers 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 sent 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 mime 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 in the 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 would 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 reconcise 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 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 up 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 wherever 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 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 disallow 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 lets them 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 a 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 packet filtering firewall essentially will only analyze data packets 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 collection 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 transport there because we also look at protocols proxy firewalls will work at layer 7 which is this 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-layered 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 known 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 the data back and send it back to the user so if there is 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 tunnel 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 mechanics so 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 tcpid without TCP IP there will be no work groups there will be no domains basically your interconnectivity will go for a toss tcpip 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 TCP 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 a 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 if config 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 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 you have completed the network security engineer full course armed with networking fundamentals protocol insights and tools like Wireshark you're now ready to safeguard digital Realms remember security is an ongoing Journey stay curious keep learning and become a guardian of safe cyber Horizons all right so we have come to the end of this video If you like this full course please 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