IP Routing

You've seen the bumper stickers: "If Mama ain't happy, ain't nobody happy." Simply put, Internet Protocol (IP) connectivity is the mama of nearly everything that goes on in information technology. If it's not working right, pretty much nothing else will be working right. IP Routing helps you understand how packets get from one IP address (on one network) to another (on a separate network). This is what the Internet--not to mention all medium-sized and large corporate intranets--is all about. If you're a router technician, you need to understand what's in these pages. That's especially true if you use Cisco Systems equipment. Ravi Malhotra spends time on standard protocols that are used by all router makers, but he devotes significant space to Interior Gateway Routing Protocol (IGRP) and Enhanced IGRP (EIGRP), which are Cisco proprietary. He shows how to do configuration work in Cisco Internetwork Operating System (IOS) exclusively.

In attacking each of the protocols he covers, Malhotra divides his exposition into several parts. First, he explains how to get the protocol running--he provides IOS listings that show how to bring it up on an example network (which he illustrates graphically). He then explains how the protocol assigns metrics to routes, and how it goes about evaluating metrics and choosing routes on the fly (this includes a look at the protocol's routing table structure). There's also coverage of any special features (such as virtual links under Open Shortest Path First--OSPF) and of troubleshooting strategies. Throughout, the author writes clearly, making effective use of graphics and realistic examples. --David Wall

Topics covered: Protocols for finding efficient routes between Internet Protocol (IP) addresses, as those protocols are implemented by Cisco routers. Covered protocols include both versions of Routing Information Protocol (RIP and RIP-2), Interior Gateway Routing Protocol (IGRP), Enhanced IGRP (EIGRP), Open Shortest Path First (OSPF), and Border Gateway Protocol 4 (BGP-4).