Network Layer

Why
The network layer is important because it allows two hosts to view each other as logically connected, even though they may be separated by half the world

What
The network layer is a protocol layer in a protocol stack that takes transport layer segments and finds the way to get the segment to the correct place. It is like the navigator.

The network layer is responsible for three important functions:
 * 1) Forwarding
 * 2) Routing
 * 3) Connection Setup

Examples of Network Layer Protocols

 * IP
 * Routing Protocol

Connection Service
A network layer that implements a connection based service makes the entire network a virtual circuit network

Connectionless Service
When a network layer only implements a connectionless based service, the network is known as a datagram network

How
Network layer protocols can be distributed across many end users and these users may then send datagrams which consist of the segment and also the address of the destination