Network Layer Computer Network (Full Explanation)
What is the Network Layer (Layer-3)?
Layer-3, known as the Network layer in the OSI model, oversees host and network addressing, manages sub-networks, and facilitates internetworking.
The Network layer is tasked with routing packets from the source to the destination, whether within a subnet or beyond. Different subnets may utilize varying addressing schemes or incompatible addressing types. Similarly, two distinct subnets might operate on different protocols that are not compatible with one another. The Network layer is responsible for routing packets from the source to the destination, effectively mapping diverse addressing schemes and protocols.
Functionalities of the Network Layer (Layer-3)
Devices operating at the Network Layer primarily concentrate on routing. This routing encompasses various tasks aimed at achieving a unified objective, which may include:
- Addressing devices and networks.
- Filling routing tables or establishing static routes.
- Managing the queuing of incoming and outgoing data, then forwarding them based on the quality of service constraints set for those packets.
- Facilitating internetworking between different subnets.
- Delivering packets to their destination with the best effort possible.
- Offering both connection-oriented and connectionless mechanisms.
Features of the Network Layer
With its standard functionalities, Layer 3 can deliver a range of features such as:
- Management of quality of service.
- Load balancing and link management.
- Security measures.
- Interrelation of various protocols and subnets with differing schemas.
- Different logical network designs over the physical network design.
- L3 VPNs and tunnels can be utilized to provide dedicated end-to-end connectivity.
The Internet Protocol is a widely recognized and implemented Network Layer protocol that enables communication between end devices over the internet. It exists in two versions: IPv4, which has dominated for decades but is now facing a shortage of address space, and IPv6, designed to replace IPv4 and hopefully address its limitations as well.
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