Routing Protocols

 

Routing Protocols

In Routing Protocol, Routing is the process of selecting paths in a network along which to send data on physical traffic. In different network operating system the network layer perform the function of protocol routing. In TCP/IP the IP protocol is the ability to form connections between different physical networks with the help of a Routing Protocol.

A system that performs this function is called an IP router. This type of device attaches to two or more physical networks and forwards packets between the networks. When sending data to a remote destination, a host passes packet to a local router.

There are two types of routing algorithm :

·         Static

·         Dynamic

Static Routing : Static routing uses pre-programmed definitions representing paths through the network. Static routing is manually performed by the network administrator. The administrator is responsible for discovering and propagating routes through the network.

Dynamic Routing : Dynamic routing algorithms allow routers to automatically discover and maintain awareness of the paths through the network. This automatic discovery can use a number of currently available dynamic routing protocols.

Following are the routing algorithms for networks :

·         Distance Vector Algorithm

·         Link State Algorithm

·         Path Vector Algorithm

·         Hybrid Algorithm

Distance Vector Routing: Distance vector algorithms use the Bellman- Ford algorithm. Distance vector algorithms are examples of dynamic routing protocols. Algorithms allow each device in the network to automatically build and maintain a local routing table or matrix.

Link State Routing : A link state is the description of an interface on a router and its relationship to neighboring routers. When applying link-state algorithms, each node uses as its fundamental data a map of the network in the form of a graph.

Shortest-Path First (SPF) Algorithm : The SPF algorithm is used to process the information in the topology database. It provides a tree representation of the network. The device running the SPF algorithm is the root of the tree.

Path Vector Routing : Distance vector and link state routing are both intra-domain routing protocols. They are used inside an autonomous system, but not between autonomous systems. Both of these routing protocols become intractable in large networks and cannot be used in Inter-domain routing. Distance vector routing is subject to instability if there are more than few hops in the domain. Link state routing needs huge amount of resources to calculate routing tables. It also creates heavy traffic because of flooding. Path vector routing is used for inter-domain routing. It is similar to Distance vector routing.

Hybrid Routing : This algorithm attempt to combine the positive attributes of both distance vector and link state protocols. Like distance vector, hybrid algorithm use metrics to assign a preference to a route. However, the metrics are more accurate than conventional distance vector algorithm.