Network Layer - Network Layer

Definition: A Local Area Network is a network that connects computers and devices in a limited geographical area such as a home, school, or office.
Node Communication: Nodes (devices) communicate via MAC (Media Access Control) addresses. Each device on a LAN has a unique MAC address which allows for direct communication.
Switches Functionality:
Switches manage and learn the MAC addresses of devices connected to their ports.
This learning allows them to forward transmissions efficiently within the local network, making communication fast and efficient.

Scalability Issues: MAC addressing works well in smaller networks but fails to scale effectively for larger networks due to:
Every network interface having a unique MAC address that is not systematically ordered.
Difficulty in tracking MAC addresses globally across different networks.
Geographical Dependence: MAC addresses are not suitable for communication over long distances because there’s no way to determine the location of a MAC address at any given time.

Need for a New Solution: Because MAC addressing is insufficient for wider network communication, IP (Internet Protocol) is introduced, which operates at the network layer.
Address Resolution Protocol (ARP):
ARP will be discussed later, showing how nodes learn about physical addressing, emphasizing its limitation to single network segments.
It highlights the need for IP as an addressing scheme that can work across different network segments.

IP Addresses: By the end of this lesson, you will be able to:
Identify what an IP address is.
Recognize how IP addresses differ from MAC addresses in their application and scalability.
Encapsulation of IP Datagrams:
Understand how IP datagrams are encapsulated within the payload of an Ethernet frame, enabling smooth transmission of data.
IP Datagram Header:
Become familiar with various fields in the IP datagram header that are critical for data routing and delivery.