This book differs from most other books on TCP/IP because it focuses on how to implement the TCP/IP protocols using the most prevalent TCP/IP routing device in use today, the Cisco router. The book provides detailed descriptions, examples, and configurations that can be used for building real-world internetworks. The text begins at a level appropriate for the TCP/IP and router novice, but advances to cover topics such as routing protocol optimization, security, implementing multiprotocol networks, and troubleshooting techniques that experienced router engineers will find useful.

The TCP/IP set of networking protocols rapidly is becoming the de facto standard for local and wide area networking. Its prominence is due in part to its openness. It is considered an open standard because no one commercial organization controls the standard. This allows all vendors an equal footing when developing TCP/IP products and gives devices from different vendors a better-than-even chance of working together properly. In addition to being an open standard, the TCP/IP protocols have proved themselves durable in the largest network in the world, the Internet. Fueling the current growth of the Internet are World Wide Web services, which make it easy for anyone who can operate a computer mouse to retrieve information from anywhere in the world. This technology is so attractive to organizations that most forward-thinking companies are building much of their information storage and retrieval systems around it on their own internal intranets. Intranets use the same TCP/IP network protocols as the public Internet but are implemented on the company's own private network.

To support this new computing paradigm, a TCP/IP network is required. To implement a TCP/IP network, you need routers. If you are involved in any way with network administration, design, or management, router technology either is or will become important to you. This book is clearly not a novel, and I don't expect it to be read as one. Of course, you can start at Chapter 1 and read all chapters in sequence, but this is not how I use my technical books. I suspect that most people will read the chapters that are of particular interest to them at different times. To support this type of use, there is some duplication of information across chapters when necessary.