Enhanced Interior Gateway Routing Protocol (EIGRP) is a unique Cisco innovation. Highly valued for its ease of deployment and fast convergence, EIGRP is commonly used in many large Enterprise networks. EIGRP maintains all of the advantages of distance-vector protocols, while avoiding the concurrent disadvantages.
EIGRP is a simple protocol to understand and deploy. It's IPv6-ready, scales effectively in a well-designed network, and provides extremely quick convergence times. Other EIGRP advantages include:
- Easy transition to IPv6 with multi-address family support for both IPv4 and IPv6 networks.
- Superior scaling of Interior Gateway Protocol (IGP) for large dynamic multipoint (DM) VPN deployments
- Very fast rapid convergence times for changes in the network topology
- Only routing table changes, not the entire routing table, are propagated, when a change occurs
- More efficient use of links, through equal cost multipath (ECMP) and unequal cost load sharing
EIGRP is an enhanced distance-vector protocol, relying on the Diffused Update Algorithm (DUAL) to calculate the shortest path to a network.