2. Physical Layer

2.2. Network Layer

3. Network Layer (Layer 3)

Function: Manages logical addressing and routing of data packets across multiple networks to reach the intended destination.

Key Responsibilities:

Assigns logical addresses (e.g., IP addresses).

Determines optimal paths for data (routing).

Handles packet forwarding, fragmentation, and reassembly.

Supports inter-network communication.

Examples:

Protocols: Internet Protocol (IP - IPv4, IPv6), ICMP, IPsec.

Devices: Routers, Layer 3 switches.

Routing Protocols: OSPF, BGP, RIP.

Example: IP address (e.g., 192.168.1.1).

Analogy: A GPS system finding the best route for packets to travel across networks.