Large-Scale IP Network Solutions (CCIE Professional Development)

Summary

EIGRP is an advanced distance-vector classless protocol that employs DUAL for faster convergence. It is based on a neighbor relationship, so it selects the best route to the destination based on real-time parameters, such as delay and bandwidth.

There are three types of DUAL messages: queries, updates, and replies. Queries are sent to all neighbors, in case a route is lost. In some networks it may take a long time for a query to be answered, which causes the router to be Stuck in Active (SIA). If this period becomes too long, the inquiring router will give up and clear its connection with the neighbor that did not reply. Preventing queries from reaching end-to-end helps the network to converge more rapidly.

Enhanced IGRP is an interior ...