Router is like a device or gateway which is used to send data form sender to the receiver end in the optimum way.

For doing this the router will share the details of the nodes in the network and the neighbour routers if receiver if from another network.

There exists two forms of routing protocols:

• Distance Vector Routing Protocol: The distance vector routing protocol will advertise the possible routes and also get new route from the neighbour nodes. The routing time and cost is estimated by the number of hopes in between the source and the destination.

• Link-State Routing Protocol: This will acknowledge the current state of link and will send information to its neighbours. This protocol uses its own algorithm for calculating the optimum path for sending data from source node to the destination node.

      Routing protocols can be divided in two categories:

• Interior Routing Protocol: In this protocol routes are distributed among all the routers inside the boundary.

• Exterior Routing Protocol: In this protocol routes are distributed among all the routers outside the boundary.

The routing table that contains information about all the nodes and the neighbouring routers looks like as in the given figure.