Lecture on Networking Full Course by SimplyLearn

Introduction to Networking

• Definition: Practice of connecting multiple computers/devices to enable communication and sharing.
• Connections: Can be wired or wireless.
• Purposes: Sharing resources, communicating, accessing the internet, etc.
• Network Protocols: Ethernet, Wi-Fi. Devices assigned IP addresses.
• Settings: Used from small businesses to large corporations; home networks to global networks.
• Career Opportunities: Network engineer, network administrator, network security specialist, clouds, wireless network engineer, etc.
• Average Salaries: In the US, around $81,000; India, 5 lakhs per annum.
• Programs: Cybersecurity bootcamps available.

Types of Networks and Components

Local Area Networks (LANs)

• Components: Cables, gateways, switches, routers, private servers, cloud services.
• Virtual LANs (VLANs): Logical division of network nodes without major infra changes.
• Benefits: Device control, file sharing, print sharing, internal connection usage.
• Example: Devices connected to an office switch (system, laptop, printer).
• IP Address: 4 sections, each max 255 value.

Wide Area Networks (WANs)

• Definition: Collection of LANs or other networks that interact.
• NAT (Network Address Translation): Masks internal IPs using public IPs.
• Advantages: Security, IP address conservation.
• Firewall: Analyses and filters traffic; prevents unauthorized remote access.
• DMZ (Demilitarized Zone): Subnet for external access without compromising internal network security.

Networking Hardware

Network Switches

• Function: Joins devices within a network and facilitates data packet exchange.
• Types: Physical or virtual switches.
• Functionality: Differentiate using IP or MAC addresses.
• Example: Company network switches.

Routers

• Role: Directs data packets, analyzes headers, and uses routing tables.
• Comparison: Like an air traffic controller.
• Importance: Determines the best path for packet delivery.

Network Security

Importance of Security

• Threat Protection: Against data loss, theft, and sabotage.
• Devices: Secures workstations, prevents hazardous spiral.
• Network Integrity: Ensures encrypted and split data transmission.
• Benefits: Increased productivity, brand trust, cost savings.
• Risks: External threats like cybercrimes, internal threats from careless behavior.

Security Strategies

• Authentication and Authorization:
  • Authentication: Verifies user identity.
  • Authorization: Determines access levels based on roles.
• Tools:
  • Firewalls: Filters traffic as per security rules.
  • VPNs: Encrypted connections between devices and networks.
  • Intrusion Prevention Systems (IPS): Blocks harmful activities.
  • Behavioral Analytics: Monitors and detects suspicious activities.

Network Layer Definitions and Concepts

TCP/IP and OSI Models

• TCP/IP: Four layers - Application, Transport, Internet, Network Access.
• OSI Model: Seven layers - Physical, Data Link, Network, Transport, Session, Presentation, Application.
• Comparisons:
  • Network Access and Physical/Data Link are comparable.
  • Internet and Network Layers are similar.
  • Transport remains the same.
  • Application combines Application/Presentation/Session.

Network Protocols

Key Protocols and Concepts

• TCP and UDP:
  • TCP: Reliable, connection-oriented (handshakes).
  • UDP: Connectionless, less reliable.
• DHCP:
  • Role: Assigns IP addresses.
  • Method: Dynamic and Manual Allocations.
  • Settings: Leases, scopes, reservations.
• DNS:
  • Role: Translates domain names to IPs.
• IPv4 and IPv6:
  • IPv4: 32-bit addresses.
  • IPv6: 128-bit addresses.
• NAT: Conserves IPs, provides security.

Network Configuration and Commands

Cluster of Commands

• ipconfig/ifconfig: Displays IP configuration.
• ping: Checks connectivity.
• tracert/traceroute: Path taken by packets.
• nslookup: DNS queries.

Key Networking Devices and Their Uses

• Hubs: Basic devices, broadcasting nature.
• Switches: More intelligent, uses MAC to direct traffic.
• Routers: Advanced, uses IPs to route traffic and manage internet access.

Routing Protocols and Algorithms

Techniques and Methods

• CIDR:
  • Allocation of IPs efficiently.
• Distance Vector Routing, Bellman-Ford Algorithm:
  • Shortest path algorithms.
• Link State Routing: Dijkstra's algorithm.

Switching Techniques

• Circuit Switching: Dedicated path, efficient for constant data.
• Packet Switching: Data divided, flexible, used widely.
• Virtual Circuit/Datagram: Variations in packet switching.

Error Detection and Correction Techniques

Methods and Protocols

• Checksum and Parity: Basic error detection.
• Hamming Code: Error correction capabilities.
• ARQ Protocols:
  • Stop-and-Wait ARQ: Wait for acknowledgment before next packet.
  • Go-Back-N ARQ: Send multiple, resend on error.
  • Selective Repeat ARQ: Only resend erroneous.

Summary and Interview Prep

Key Questions to Consider

• OSI Model layers and their functions.
• Differences between unicast, multicast, and broadcast.
• Functions of DNS, DHCP, and common network commands.
• Role and types of firewalls.
• Advantages of distributed processing.
• Concepts of TCP/IP and encapsulation.

By focusing on these summarised points from the detailed lecture, a student can have a well-rounded understanding of core networking principles and prepare effectively for related interviews.