Enhanced Interior Gateway Routing Protocol

Enhanced Interior Gateway Routing Protocol is a distance-vector routing protocol which is advanced mainly used by the network to automate the decisions of routing and its configuration.

EIGRP is mainly used to the sharing of route data with its neighbours within the network.

EIGRP is a dynamic routing protocol by which routers automatically share route information. This eases the workload on a network administrator who does not have to configure changes to the routing table manually.

In addition to the routing table, EIGRP uses the following tables to store information:

• Neighbour Table: It will keep track of the IP addresses of that routers which are connected to the other router.

• Topology Table:  It stores the data that comes from the neighbour routing tables. It also store the metrics which contains the information about the nodes in the network.

Information in the topology table may be inserted into the router's routing table and can then be used to forward traffic. If the network changes, for example, a physical link fails or is disconnected, the path will become unavailable.

EIGRP is designed to detect these changes and will attempt to find a new path to the destination. The old path that is no longer available is removed from the routing table.