Enhances Interior Gateway Routing Protocol; EIGRP is an enhanced distance vector protocol, relying on the Diffused Update Algorithm (DUAL) to calculate the shortest path to a destination within a network.
EIGRP is an advance distance vector protocol, one of its core strengths is its fast network convergence capabilities, unlike other routing protocols EIGRP keeps feasible successor routes right into the routing table, this allows millisecond convergence should the successor route fail.
Flexible in summarization:
Unlike OSPF, EIGRP allows you to summarize anywhere, in bigger environments where routers are advertising hundreds of networks, route summarization can greatly enhance router's and network operational capabilities, its less taxing on CPU / memory and cheaper to run / maintain.
One of the core weaknesses is its cisco proprietary, it does not interoperate with other vendor devices, and so running it in a mixed environment is not an option.
EIGRP Operational requirement:-
In terms of operational requirement, EIGRP is simple to configure and inexpensive to run.
EIGRP uses partial and incremental updates, these updates are only triggered when a change occurs and when it does, it only sends the changed information to the routers affected, this greatly reduces bandwidth utilization.
EIGRP does not require a hierarchical network design to operate efficiently.
EIGRP is protocol independent, apart from ipv4 /6 it also supports IPX and AppleTalk, customers who are using these protocols can leverage the protocol independent EIGRP capabilities to achieve higher return on investments.
EIGRP is less complex to implement and it also offers efficient route calculations when compared with OSPF, e.g. EIGRP uses bandwidth, delay, reliability and load when calculating optimal routes where as OSPF only takes bandwidth into consideration when calculating optimal routes.
Keeping the above points in mind, EIGRP will be more viable commercially provided that it’s a full end to end cisco implementation; EIGRP can also redistribute routing information with other routing protocol with router redistribution or using an exterior gateway protocol (BGB).
(Open Shortest Path First) is a classless, link-state routing protocol. The current version of OSPF for IPv4 is OSPFv2 introduced in RFC 1247 and updated in RFC 2328 by John Moy. In 1999, OSPFv3 for IPv6 was published in RFC 2740. (OU CCNA Course)