Introduction

Enhanced IGRP, or EIGRP, is one of the most versatile interior routing protocols available, and is often the protocol of choice in all-Cisco environments. Therefore, you should have a strong working knowledge of EIGRP. Whether you plan to implement QoS on your network today, in the future, or never, strongly consider EIGRP when choosing an interior routing protocol. EIGRP is Cisco s proprietary routing protocol, and you can rest assured that Cisco will continue to improve and grow this routing protocol. In addition, because there are no standards organizations with which to contend, Cisco can easily update and improve this protocol without compromise.

EIGRP is a very capable routing protocol with support for IP, IPX, and AppleTalk. With new enhancements, such as EIGRP Stubs, EIGRP is now more scalable than ever, and is becoming more viable every day. In fact, at Networks 2000 (Cisco s yearly convention) the person presenting the EIGRP session discussed the possibility that Cisco would soon greatly reduce the impact of the very nasty problem of Stuck-in-Active routes. It will be interesting to watch as this is implemented and deployed.

In the meantime, however, EIGRP remains one of the cleanest and easiest to configure of all the interior routing protocols available. In this chapter, you will learn some of the features and theories of EIGRP in the hope that you will have all of the information you need to make decisions about deploying EIGRP on your network. Additionally, you will see advanced EIGRP configuration examples to illustrate...