For end to end IP communication just having the forwarding path is not enough, it is necessary to have the reverse path as well to reach the network. If one can reach one host of one network it doesn't mean one can reach all host of that network. For end to end IP communication router should have route to reach all networks. Initially router has only the route to reach directly connected networks. Router can learn the route of the other network by two processes: Statically and Dynamically. In static Routing protocol the best path selection is done by AD value and in dynamic Routing protocol the best path selection is done through Metric Value. Static Routing protocol is used where it is a simple architecture while dynamic routing protocol is used where complexity increases. It is not advisable to use Dynamic Routing Protocol for simple architecture as processing power is high when we make dynamic entries. In this paper we proposed the use of some specified protocols according to the classification. The emphasis of this paper is not to present protocols in detail but to present main features of wide variety of different protocols depending upon their requirements.

AD Value Metric Value AS Number Cost Process ID LSA Value LSU Value.