Understanding EIGRP #1
prepared by SURAJ (imeansuraj@gmail.com) Replaced the Interior Gateway Routing Protocol It was Cisco proprietary till mid-2013. Doesn’t use UDP or TCP since it doesn’t need the port numbers to work with. It uses Cisco’s Reliable Transport Protocol (protocol number 88). Administrative Distance of a routing information from an EIGRP enabled router outside the Autonomous System is 170 and inside the Autonomous System is 90. Creates an autonomous system including all the routers that it wants to transfer data within, this autonomous system is of 16 bits. New metric of EIGRP is of 64 bits, the earlier composite metric of EIGRP was of 48 bits while IGRP had a metric of 24 bits Working - Discovers neighbours by sending hello packets - Exchanges information with hellos via 224.0.0.10 (multicast address for EIGRP) - As soon as the router doesn’t receive them in the hold time it will drop the neighbour relationship called adjacency and EIGRP might have to look for an