Chapter 5: Enhanced Interior Gateway Routing Protocol (EIGRP)
Exam Objectives
Describing the features and characteristics of EIGRP
Distinguishing EIGRP from IGRP
Describing EIGRP routing decision criteria
Describing EIGRP route updates and convergence
Describing EIGRP routing tables and operation
Understanding the Diffusing Update Algorithm (DUAL)
Deploying EIGRP
Verifying and troubleshooting EIGRP on a Cisco router
As the name implies, the Cisco-proprietary Enhanced Interior Gateway Routing Protocol (EIGRP) is an interior gateway protocol that contains many advantages over Routing Information Protocol (RIP) and its superseded predecessor, the Interior Gateway Routing Protocol (IGRP). EIGRP is the enhanced version of IGRP. Like RIP, IGRP is known as a distance vector protocol, but it uses a dramatically improved distance vector algorithm to determine the best path to a particular destination. IGRP relies more heavily on the bandwidth and delay metrics of a route as opposed to RIP, which relies on the distance of a route.
EIGRP includes features commonly found in more advanced link-state protocols. EIGRP also uses a more advanced method of loop mitigation than both RIP and IGRP, providing a 100-percent loop-free environment.
Other benefits of EIGRP include high scalability with minimal network overhead and very fast convergence speeds. To fully understand the capabilities of EIGRP, it is beneficial to first take a look at the protocol on which it is based, namely IGRP.
IGRP — ...
