TCPIP_02.book Page i Thursday, January 5, 2012 12:32 PM What Readers Are Saying about The TCP/IP Guide “Whenever I need information or clarification on any TCP/IP or OSI related topic, The TCP/IP Guide is the first place I go.” –SHAWN BRIDGLAL, COMPUTER ENGINEERING TECHNOLOGIST “ . . . an extremely readable and lucid document on a very involved subject. The TCP/IP Guide is an immense piece of work, but it does the best job I’ve seen of making a complicated subject understandable.” –PETER BICE, CONSULTING SOFTWARE ENGINEER “An absolute must-have for the serious student of networking, and those who just want a greater understanding of the technical world around them. Its level of detail is excellent, yet its simple explanations and analogies of even the most complex subjects make this work unparalleled. Even for the experienced student its coverage of the basics can make things so much clearer.” –IAIN DENTON, NETWORKING STUDENT “Written in Charles M. Kozierok’s familiar down-to-earth style, The TCP/IP Guide is at once easy enough to understand that it should be an excellent starting place for beginners to learn networking—and at the same time, thorough and in-depth enough to make it a must-have reference for advanced users and professionals.” –BILLY GRIFFIS, COMPUTER TECHNICIAN “In The TCP/IP Guide, Charles M. Kozierok thoroughly explains the details of many complex networking processes in a straightforward, orderly manner. He is an excellent teacher—his lucid understanding of his subject matter and his awareness of his audience are evident in every explanation of the many TCP/IP topics he addresses. The TCP/IP Guide is a valuable resource for anyone wanting to thoroughly understand the details of how TCP/IP networking works.” –DAVID WILLIAMS, TEACHER “Everyone who is starting off their IT career or wanting to increase their knowledge of TCP/IP would benefit enormously by buying this book.” –KIRK PASCOE, INFORMATION SYSTEMS ENGINEER TCPIP_02.book Page ii Thursday, January 5, 2012 12:32 PM TCPIP_02.book Page iii Thursday, January 5, 2012 12:32 PM THE TCP/IP GUIDE A Comprehensive, Illustrated Internet Protocols Reference by Charles M. Kozierok San Francisco TCPIP_02.book Page iv Thursday, January 5, 2012 12:32 PM THE TCP/IP GUIDE. Copyright © 2005 by Charles M. Kozierok. All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. 12 11 10 5 6 7 8 9 10 Printed in the United States of America ISBN-10: 1-59327-047-X ISBN-13: 978-1-59327-047-6 Publisher: William Pollock Production Manager: Susan Berge Cover and Interior Design: Octopod Studios Developmental Editor: William Pollock Technical Reviewers: Fernando Gont, Barry Margolin Copyeditors: Marilyn Smith, Lisa Theobald, Mark Nigara Compositor: Riley Hoffman Proofreader: Stephanie Provines For information on book distributors or translations, please contact No Starch Press, Inc. directly: No Starch Press, Inc. 38 Ringold Street, San Francisco, CA 94103 phone: 415.863.9900; fax: 415.863.9950; [email protected]; http://www.nostarch.com Library of Congress Cataloging-in-Publication Data Kozierok, Charles. The TCP/IP guide : a comprehensive, illustrated internet protocols reference / Charles Kozierok. p. cm. Includes index. ISBN 1-59327-047-X 1. TCP/IP (Computer network protocol) I. Title. TK5105.585.K69 2005 004.6'2--dc22 2004008863 No Starch Press and the No Starch Press logo are registered trademarks of No Starch Press, Inc. Other product and company names mentioned herein may be the trademarks of their respective owners. Rather than use a trademark symbol with every occurrence of a trademarked name, we are using the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The information in this book is distributed on an “As Is” basis, without warranty. While every precaution has been taken in the preparation of this work, neither the author nor No Starch Press, Inc. shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in it. TCPIP_02.book Page v Thursday, January 5, 2012 12:32 PM D E D I C A T I O N This book is dedicated to my family: my wife, Robyn, and my three sons, Ryan, Matthew, and Evan. I suppose that it’s a cliché to dedicate a book to your wife. If so, it’s for a very good reason. Who plays a more important role in the life of an author than his or her spouse? Robyn is my partner—the person who is always there and the one who shares my life in so many ways. The expression about a great woman being behind every good man is true, yet my wife is deserving of recognition for reasons that go far beyond the usual one of being “supportive.” She agreed to take on a regular working position to make it possible for me to spend time on a very long project with an uncertain payoff. She took on most of the tasks of taking our children to school and dealing with their needs, to give me time to write. She also gracefully agreed to “do without” many things that many other wives would not have been too happy about forgoing. But most of all, she deserves a world of credit for putting up with me. For constantly reassuring me that it was okay that I was spending years on a project that might not be successful. For listening to me talk for countless hours, and for giving her opinions on many portions of my writing, all on a subject that really doesn’t interest her. And most important, for encouraging me when I felt this was a waste of time, and even kicking me in the butt when I felt like giving up. Without Robyn, this book simply would not exist. Thanks, R. My three boys deserve credit for similar reasons, but to a lesser extent. They have had to put up with my constantly sitting at the computer, trying to tune them out so I could concentrate; my too-frequent grouchy moods; and my reluctance to spend time with them when I had work on my plate. I am sure there were many times that they wished I just had a regular “day job.” TCPIP_02.book Page vi Thursday, January 5, 2012 12:32 PM Ryan, my big boy, has been very patient in waiting for me to finish this project so we can resume several activities that we used to engage in regularly. Matthew, my fun-loving and rambunctious middle son, has also had to deal with me not being able to spend as much time as I would have liked with him. And little Evan has had a father working on a long-term project for his entire life! All three of my boys have been very understanding and provided me with much-needed joy and laughter at times when I needed them most. vi Dedication TCPIP_02.book Page vii Thursday, January 5, 2012 12:32 PM B R I E F C O N T E N T S Contents in Detail.........................................................................................................xiii List of Figures................................................................................................................xlv List of Tables..................................................................................................................lv Acknowledgments.........................................................................................................lxv About the Author.........................................................................................................lxvii Introduction.................................................................................................................lxix SECTION I: TCP/IP OVERVIEW AND BACKGROUND INFORMATION PART I-1: NETWORKING FUNDAMENTALS Chapter1: Networking Introduction, Characteristics, and Types...........................................5 Chapter2: Network Performance Issues and Concepts......................................................31 Chapter3: Network Standards and Standards Organizations............................................45 Chapter4: A Review of Data Representation and the Mathematics of Computing.................61 PART I-2: THE OPEN SYSTEMS INTERCONNECTION (OSI) REFERENCE MODEL Chapter5: General OSI Reference Model Issues and Concepts..........................................81 Chapter6: OSI Reference Model Layers........................................................................101 Chapter7: OSI Reference Model Summary....................................................................113 PART I-3: TCP/IP PROTOCOL SUITE AND ARCHITECTURE Chapter8: TCP/IP Protocol Suite and Architecture..........................................................121 TCPIP_02.book Page viii Thursday, January 5, 2012 12:32 PM SECTION II: TCP/IP LOWER-LAYER CORE PROTOCOLS PART II-1: TCP/IP NETWORK INTERFACE LAYER PROTOCOLS Chapter9: TCP/IP Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) Overview and Fundamentals..................................................................................139 Chapter10: PPP Core Protocols: Link Control, Network Control, and Authentication...........155 Chapter11: PPP Feature Protocols.................................................................................167 Chapter12: PPP Protocol Frame Formats........................................................................181 PART II-2: TCP/IP NETWORK INTERFACE/INTERNET LAYER CONNECTION PROTOCOLS Chapter13: Address Resolution and the TCP/IP Address Resolution Protocol (ARP).............203 Chapter14: Reverse Address Resolution and the TCP/IP Reverse Address Resolution Protocol (RARP).....................................................................................................227 PART II-3: INTERNET PROTOCOL VERSION4 (IP/IPV4) Chapter15: Internet Protocol Versions, Concepts, and Overview......................................235 Chapter16: IPv4 Addressing Concepts and Issues..........................................................241 Chapter17: Classful (Conventional) Addressing.............................................................255 Chapter18: IP Subnet Addressing (Subnetting) Concepts.................................................273 Chapter19: IP Subnetting: Practical Subnet Design and Address Determination Example.....297 Chapter20: IP Classless Addressing—Classless Inter-Domain Routing (CIDR)/Supernetting..............................................................................................315 Chapter21: Internet Protocol Datagram Encapsulation and Formatting..............................329 Chapter22: IP Datagram Size, Fragmentation, and Reassembly.......................................339 Chapter23: IP Routing and Multicasting........................................................................351 PART II-4: INTERNET PROTOCOL VERSION6 (IPV6) Chapter24: IPv6 Overview, Changes, and Transition.....................................................365 Chapter25: IPv6 Addressing........................................................................................373 Chapter26: IPv6 Datagram Encapsulation and Formatting...............................................401 Chapter27: IPv6 Datagram Size, Fragmentation, Reassembly, and Routing.......................415 viii Brief Contents TCPIP_02.book Page ix Thursday, January 5, 2012 12:32 PM PART II-5: IP-RELATED FEATURE PROTOCOLS Chapter28: IP Network Address Translation (NAT) Protocol.............................................425 Chapter29: IP Security (IPsec) Protocols........................................................................449 Chapter30: Internet Protocol Mobility Support (Mobile IP)...............................................475 PART II-6: IP SUPPORT PROTOCOLS Chapter31: ICMP Concepts and General Operation......................................................507 Chapter32: ICMPv4 Error Message Types and Formats..................................................521 Chapter33: ICMPv4 Informational Message Types and Formats.......................................535 Chapter34: ICMPv6 Error Message Types and Formats..................................................547 Chapter35: ICMPv6 Informational Message Types and Formats.......................................557 Chapter36: IPv6 Neighbor Discovery (ND) Protocol.......................................................575 PART II-7: TCP/IP ROUTING PROTOCOLS (GATEWAY PROTOCOLS) Chapter37: Overview of Key Routing Protocol Concepts.................................................591 Chapter38: Routing Information Protocol (RIP, RIP-2, and RIPng).......................................597 Chapter39: Open Shortest Path First (OSPF)..................................................................625 Chapter40: Border Gateway Protocol (BGP/BGP-4).......................................................647 Chapter41: Other Routing Protocols.............................................................................677 PART II-8: TCP/IP TRANSPORT LAYER PROTOCOLS Chapter42: Overview and Comparison of TCP and UDP................................................689 Chapter43: TCP and UDP Addressing: Ports and Sockets................................................695 Chapter44: TCP/IP User Datagram Protocol (UDP).........................................................711 Chapter45: TCP Overview, Functions, and Characteristics..............................................719 Chapter46: Transmission Control Protocol (TCP) Fundamentals and General Operation......727 Chapter47: TCP Basic Operation: Connection Establishment, Management, and Termination..........................................................................................................745 Chapter48: TCP Message Formatting and Data Transfer.................................................769 Chapter49: TCP Reliability and Flow Control Features....................................................793 Brief Contents ix