BSCI Exam Cram™ 2 (Exam 642-801)

EIGRP Support of VLSM and Route Summarization

EIGRP automatically summarizes routes at classful major network boundaries on attached interfaces. This is one of the attributes of its distance-vector behavior. Route summarization reduces the number of routing table entries that are advertised to neighbor routers, which results in fewer routing table lookups and enhances overall network performance. For example, routes for 10 contiguous Class C networks, such as 192.168.1.0/24 through 192.168.10.0/24, would be advertised by EIGRP with just a single summary route: 192.168.1.0/16.

EIGRP supports both automatic route summarization and manual summarization. EIGRP, like its predecessor IGRP, auto-summarizes at major network boundaries by default, although ...