Enhanced_IGRP - CHAPTER 40 Chapter Goals Identify the four...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
CHAPTER 40-1 Internetworking Technologies Handbook 1-58705-001-3 40 Chapter Goals Identify the four key technologies employed by Enhanced Interior Gateway Routing Protocol (EIGRP). Understand the Diffusing Update Algorithm (DUAL), and describe how it improves the operational efficiency of EIGRP. Learn how to use EIGRP to interconnect networks with different routing protocols as well as different routed protocols. Discover how it is possible to migrate gradually to EIGRP. Enhanced Interior Gateway Routing Protocol The Enhanced Interior Gateway Routing Protocol (EIGRP) represents an evolution from its predecessor IGRP (refer to Chapter 42, “Interior Gateway Routing Protocol”). This evolution resulted from changes in networking and the demands of diverse, large-scale internetworks. EIGRP integrates the capabilities of link-state protocols into distance vector protocols. Additionally, EIGRP contains several important protocols that greatly increase its operational efficiency relative to other routing protocols. One of these protocols is the Diffusing update algorithm (DUAL) developed at SRI International by Dr. J.J. Garcia-Luna-Aceves. DUAL enables EIGRP routers to determine whether a path advertised by a neighbor is looped or loop-free, and allows a router running EIGRP to find alternate paths without waiting on updates from other routers. EIGRP provides compatibility and seamless interoperation with IGRP routers. An automatic-redistribution mechanism allows IGRP routes to be imported into EIGRP, and vice versa, so it is possible to add EIGRP gradually into an existing IGRP network. Because the metrics for both protocols are directly translatable, they are as easily comparable as if they were routes that originated in their own autonomous systems (ASs). In addition, EIGRP treats IGRP routes as external routes and provides a way for the network administrator to customize them. This chapter provides an overview of the basic operations and protocol characteristics of EIGRP. EIGRP Capabilities and Attributes Key capabilities that distinguish EIGRP from other routing protocols include fast convergence, support for variable-length subnet mask, support for partial updates, and support for multiple network layer protocols.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
40-2 Internetworking Technologies Handbook 1-58705-001-3 Chapter 40 Enhanced Interior Gateway Routing Protocol Underlying Processes and Technologies A router running EIGRP stores all its neighbors’ routing tables so that it can quickly adapt to alternate routes. If no appropriate route exists, EIGRP queries its neighbors to discover an alternate route. These queries propagate until an alternate route is found. Its support for variable-length subnet masks permits routes to be automatically summarized on a network number boundary. In addition, EIGRP can be configured to summarize on any bit boundary at any interface. EIGRP does not make periodic updates. Instead, it sends partial updates only when the metric for a route
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Enhanced_IGRP - CHAPTER 40 Chapter Goals Identify the four...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online