Cisco IOS in a Nutshell documents the most important bits of the frequently arcane IOS command line from aaa accounting to write, thereby providing a valuable resource to everyone who works with IOS. Three cheers for the Nutshell format! There may be no better printed style for command-line environments, like the Internetwork Operating System (IOS) that runs on Cisco Systems routers. The reference section--which makes up about 60 per cent of this book--summarises each command (again, they're not all covered, but the ones that aren't are pretty obscure) with a statement of its scope (global, interface, line, or whatever), followed by generalised syntax summaries in the style of Unix man pages (these indicate the legal combinations of switches and parameters). Then, a detailed discussion of each switch and parameter clarifies what each is for. The whole reference section is alphabetical, with lettered dark boxes on the pages' outer edges that are easy to scan while flipping pages rapidly.

Prior to the reference section, the author explains how the IOS interface refers to and controls aspects of routers, such as lines and interfaces. He does a great job of it, too--you could do far worse than to read his explanations before going to work under IOS for the first time. The other great value of this early section is in the author's discussion of how to configure a new router by bringing interfaces, data-communication protocols (like TCP/IP), routing protocols (like Border Gateway Protocol, or BGP), and services like Domain Name Service (DNS) online. This book is a tremendous value for Cisco engineers. --David Wall

Topics covered: How to configure a Cisco Systems router with the Internetwork Operating System (IOS). The most popular commands are documented, and there's a tutorial section that gets readers oriented in the Cisco way of thinking about a router's work. The author uses IOS 12.x as his baseline, though users of older versions will find his work valuable.