Cisco IPv6 Training IPv6 EIGRP

An EIGRPv6 / EIGRPv4 Overview

By Charles Ross CCNP #CSCO10444244

Now if you’re new to Cisco IT networking, you may not be totally sure about the EIGRPv6 protocol. I hope this article will quickly clarify things.

First of all, EIGRP stands for Enhanced Interior Gateway Routing Protocol; it’s the enhanced version of the Interior Gateway Routing Protocol (IGRP) and was created by Cisco Systems. Currently, there are two versions of EIGRP; version 4 (EIGRPv4) and version 6 (EIGRPv6); EIGRPv4 runs on IPv4 networks and EIGRPv6 runs on IPv6 networks.

EIGRPv6 pretty much operates in the same manner as its predecessor EIGRPv4; and both versions of EIGRP performs the following:

Allows an EIGRP router(s) to build a topology table from each of its neighbor's advertisements; and then only the best routes from the topology table are placed into the router’s routing table. The best route to a particular destination is called a “successor” and the second best route to a particular destination is called a “feasible successor”.

Both versions of EIGRP, use the Diffusing Update Algorithm or (DUAL) for fast convergence and to guarantee loop-free operation.

Both versions of EIGRP, only send routing updates about paths that have changed, once an EIGRP network has converged.

Both versions of EIGRP, allow EIGRP router interfaces to send hello packets every 5 seconds on high bandwidth links and every 60 seconds on low bandwidth multipoint links to verify neighboring router connectivity.

Both versions of EIGRP, rely on the metrics of Bandwidth, Delay, Reliability, and Load, to determine routes but, mainly uses Bandwidth and Delay. The entire EIGRP metric formula is:

256*((K₁*Bw) + (K₂*Bw)/(256-Load) + (K₃*Delay)*(K₅/(Reliability + K₄)))

Also, both versions of EIGRP use the Reliable Transport Protocol (RTP) when necessary to guarantee the delivery of EIGRP packets.

To your success,

Charles Ross

CCNP #CSCO10444244