Layer 2 - Network Layer

This is the layer which is concerned with getting information from one machine on a network to another. It provides  connectivity and path
selection between two end systems. 

Routing is also done at this layer.

In our railroad analogy, the network layer is the manifest which tells people which product goes on which train and in which car, and how that cargo gets to it's destination. In other words, which route through the country the train would have to travel to deliver it's products.

An Example Of Routing

Another Example