Cisco Press - Inside Cisco IOS Software Architecture.pdf - Cisco Press(1) - andri98z

Inside Cisco IOS Software Architecture

Cisco Press logo is a trademark of Cisco Systems, Inc.

Published by:

Cisco Press

201 West 103rd Street

Indianapolis, IN 46290 USA

by any means, electronic or mechanical, including photocopying, recording, or by any

information storage and retrieval system, without written permission from the publisher,

except for the inclusion of brief quotations in a review.

Printed in the United States of America 1 2 3 4 5 6 7 8 9 0

Library of Congress Cataloging-in-Publication Number: 99-64092

Warning and Disclaimer

This book is designed to provide information about Cisco's proprietary Internetwork

Operating System (IOS) software architecture. Every effort has been made to make this

book as complete and as accurate as possible, but no warranty or fitness is implied.

The information is provided on an "as is" basis. The author, Cisco Press, and Cisco

Systems, Inc., shall have neither liability nor responsibility to any person or entity with

respect to any loss or damages arising from the information contained in this book or from

the use of the discs or programs that may accompany it.

The opinions expressed in this book belong to the author and are not necessarily those of

Cisco Systems, Inc.

Trademark Acknowledgments

All terms mentioned in this book that are known to be trademarks or service marks have

been appropriately capitalized. Cisco Press or Cisco Systems, Inc. cannot attest to the

accuracy of this information. Use of a term in this book should not be regarded as

affecting the validity of any trademark or service mark.

Cisco Systems has more than 200 offices in the following countries. Addresses,

phone numbers, and fax numbers are listed on the Cisco Connection Online Web

site at http://www.cisco.com/offices .

• Argentina

• Australia

• Austria

• Belgium

• Brazil

• Canada

• Chile

• China

• Colombia

• Costa Rica

• Croatia

• Czech Republic

• Denmark

• Dubai, UAE

• Finland

• France

• Germany

• Greece

• Hong Kong

• Hungary

• India

• Indonesia

• Ireland

• Israel

• Italy

• Japan

• Korea

• Luxembourg

• Malaysia

• Mexico

• The Netherlands

• New Zealand

• Norway

• Peru

• Philippines

• Poland

• Portugal

• Puerto Rico

• Romania

• Russia

• Saudi Arabia

• Singapore

• Slovakia

• Slovenia

• South Africa

• Spain

• Sweden

• Switzerland

• Taiwan

• Thailand

• Turkey

• Ukraine

• United Kingdom

• United States

• Venezuela

Dedications

Vijay Bollapragada:

To my best friend and wife, Leena, for her love and support and sacrifice to let me write

this book; to my two lovely children, Amita and Abhishek; to my parents; and to all my

friends.

Curtis Murphy:

To my darling wife, Ann, for her ever cheerful smile, her loving support, and her

willingness to sacrifice some of our quiet time together to allow me to write this book.

Russ White:

To my wife, Lori, who supports me through the trials and tribulations of book writing, and

my daughter Rebekah, who's learning not to play with the mouse and keyboard while I'm

working. (I'll install some software for you soon.) I would like to thank God for giving me

the opportunity, time, and talent to embark on these bold ventures.

Feedback Information

At Cisco Press, our goal is to create in-depth technical books of the highest quality and value. Each book is

crafted with care and precision, undergoing rigorous development that involves the unique expertise of

members from the professional technical community.

Readers' feedback is a natural continuation of this process. If you have any comments regarding how we

could improve the quality of this book, or otherwise alter it to better suit your needs, you can contact us

through e-mail at ciscopress@mcp.com . Please make sure to include the book title and ISBN in your

message.

We greatly appreciate your assistance.

About the Technical Reviewers

Michael Brown , CCIE #2249, is an ISP Support engineer for Cisco Systems. He earned his bachelor of

science degree in electrical engineering from North Carolina State University. In the 11 years he has

worked in the networking industry, he has supported a variety of customer networks and technologies. He

spent three and half years supporting customers in the Cisco Technical Assistance Center in Brussels,

Belgium, before joining the Cisco ISP Support team in Research Triangle Park, NC. He has taught several

router architecture courses to Cisco internal audiences and to Cisco customers.

Jennifer DeHaven Carroll , CCIE #1402, is a principal consultant for Lucent Technologies, NetworkCare

Professional Services. She earned her bachelor of science degree in computer science from University of

California, Santa Barbara. In the past 11 years, Jennifer has planned, designed, and implemented many

Cisco-based networks, utilizing all the various IOS switching and packet queuing methods.

Ron Long is the Director of Internet Development for a large, southwestern integrated communications

provider. He is responsible for the planning, extension, development, and implementation of Internet

services and Layer 2-3 access. Ron entered the networking industry in 1995 when he co-founded an ISP in

a small town in Texas. Since then, Ron has provided consulting services and has implemented Cisco

solutions to Fortune 1000 companies across the globe.

Alexander Marhold , CCIE #3324, holds an MSC degree in industrial electronics and an MBA. He works as

Senior Consultant and Manager at PROIN, a leading European training and consulting company. His focus

areas are core routing and service provider issues, such as MPLS, Local Loop, Network Design, and

Implementation. Beside his works as a consultant, Alexander is also a CCSI and develops and holds

specialized trainings in the service provider area. His previous working experiences also include academic

teaching at a polytechnical university for telecommunications, as well as working as CIM-Project Manager in

the chemical industry.

Acknowledgments

This book would have not been possible without the help of many people whose many comments and

suggestions improved the end result. First, we want to thank the technical reviewers for the book: Mike

Brown, Chris Shaker, Derek Iverson, Alexander Marhold, Jennifer Carroll, and Ron Long. Thanks also to

Bob Olsen, Eric Osborne, Siva Valliappan, Ruchi Kapoor, and Lance McCallum for valuable feedback.

Finally, we want to thank Brett Bartow, Chris Cleveland, as well as the other people at Cisco Press for

keeping us on track and for getting the book published.

Introduction

Venture into any bookstore today and you can find numerous books on internetworking covering a wide

range of topics from protocols to network design techniques. There's no question that internetworking has

become a popular field with the enormous growth of the Internet and the increasing convergence of voice,

video, and data. Cisco has built a very successful business selling the equipment that forms the network

infrastructure—by some accounts, Cisco has more than 85 percent of the market—and at the same time

has seen its Cisco IOS Software become a de facto industry standard. Yet, although plenty of material is

written about network design and the protocols IOS supports, very little information is available from

sources other than Cisco.

This lack of information is understandable—IOS is proprietary, after all—but it nevertheless leaves network

implementers at a disadvantage. During our experience helping design and troubleshoot IOS-based

networks, we've seen many cases where limited IOS architectural knowledge either contributed to a

problem or made it more difficult to solve. In addition, we collectively have answered countless numbers of

questions (and dispelled some myths) from bewildered Cisco customers about the workings of various IOS

features.

This book is an attempt to bring together, in one place, the wealth of information about the architecture and

the operation of IOS. Some of this information has been made public previously through forums, Cisco

presentations, and the Cisco Technical Assistance Center. Most of the information you cannot find in the

Cisco IOS documentation.

Objectives

Inside Cisco IOS Software Architecture is intended to be an IOS "shop manual" for network designers,

implementers, and administrators. The objective of this book is to describe key parts of the architecture and

the operation of the IOS software. This book also covers the architecture of some of Cisco's hardware

platforms. Because IOS is a specialized embedded operating system tightly coupled to the underlying

hardware, it's difficult to describe the software without also considering the hardware architecture. Note,

however, that this book is not meant to be an exhaustive manual for Cisco hardware. The hardware

descriptions are provided only to help illustrate unique features in the IOS software. You might notice that

this book does not cover many of the Cisco platforms; in particular, this book does not cover any of the

Catalyst switch products, and it omits many of the access routers. In most cases, the missing platforms

either are similar to ones that are covered or, in the case of the Catalyst switches, would be best treated in

a separate text of their own.

Cisco Press - Inside Cisco IOS Software Architecture.pdf

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: