Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com Mission-Critical Network Planning Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com For a listing of recent titles in the Artech House Telecommunications Library, turn to the back of this book. Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com Mission-Critical Network Planning Matthew Liotine Artech House, Inc. Boston • London www.artechhouse.com Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com Library of Congress Cataloging-in-Publication Data Library of Congress CIP information is available on request. British Library Cataloguing in Publication Data Liotine, Matthew Mission-critical network planning. —(Artech House telecommunications library) 1. Computer networks—Design and construction 2. Business enterprises—Computer networks I. Title 004.6 ISBN 1-58053-516-X Cover design by Igor Valdman © 2003 ARTECH HOUSE, INC. 685 Canton Street Norwood, MA 02062 All rights reserved. Printed and bound in the United States of America. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, includ- ing photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Artech House cannot attest to the accuracy of this informa- tion. Use of a term in this book should not be regarded as affecting the validity of any trade- mark or service mark. International Standard Book Number: 1-58053-516-X A Library of Congress Catalog Card number is available for this book. 10987654321 Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com To Camille and Joseph—this is for them to remember me by. 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Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com Contents Foreword xv Preface xvii Acknowledgments xviii CHAPTER 1 Introduction 1 1.1 What Is Mission Critical? 1 1.2 Purpose of the Book 2 1.3 Network Continuity Versus Disaster Recovery 2 1.4 The Case for Mission-Critical Planning 4 1.5 Trends Affecting Continuity Planning 5 1.6 Mission Goals and Objectives 6 1.7 Organization of the Book 7 References 8 CHAPTER 2 Principles of Continuity 9 2.1 Fault Mechanics 9 2.1.1 Disruptions 10 2.1.2 Containment 11 2.1.3 Errors 11 2.1.4 Failover 12 2.1.5 Recovery 13 2.1.6 Contingency 13 2.1.7 Resumption 14 2.2 Principles of Redundancy 14 2.2.1 Single Points of Failure 14 2.2.2 Types of Redundancy 16 2.3 Principles of Tolerance 20 2.3.1 Fault Tolerance 21 2.3.2 Fault Resilience 22 2.3.3 High Availability 22 2.4 Principles of Design 22 2.4.1 Partitioning 23 2.4.2 Balance 23 vii Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com 2.4.3 Network Scale 25 2.4.4 Complexity 27 2.5 Summary and Conclusions 28 References 29 CHAPTER 3 Continuity Metrics 31 3.1 Recovery Metrics 32 3.1.1 Recovery Time Objective 32 3.1.2 Recovery Point Objective 35 3.1.3 RTO Versus RPO 36 3.2 Reliability Metrics 36 3.2.1 Mean Time to Failure 37 3.2.2 Failure Rate 37 3.2.3 Mean Time to Recovery 38 3.2.4 Mean Time Between Failure 38 3.2.5 Reliability 40 3.3 Availability Metrics 42 3.4 Exposure Metrics 47 3.5 Risk/Loss Metrics 47 3.6 Cost Metrics 48 3.7 Capacity Metrics 52 3.7.1 Utilization 52 3.7.2 Bandwidth 53 3.7.3 Overhead 54 3.8 Performance Metrics 55 3.8.1 Latency 55 3.8.2 Response Time 57 3.8.3 Loss 57 3.8.4 Error 57 3.8.5 Throughput 58 3.9 Summary and Conclusions 59 References 60 CHAPTER 4 Network Topology and Protocol Considerations for Continuity 63 4.1 Network Topology 63 4.1.1 Fundamental Topologies 64 4.1.2 Mesh Topologies 65 4.1.3 Ring Topologies 67 4.1.4 Tiered Topologies 68 4.1.5 Edge Topologies 69 4.1.6 Peer-to-Peer Topologies 69 4.2 Network Protocol Considerations 70 4.3 Summary and Conclusions 71 References 72 viii Contents Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com CHAPTER 5 Networking Technologies for Continuity 73 5.1 Local Area Networks 73 5.1.1 Ethernet 74 5.1.2 Switching Versus Segmenting 76 5.1.3 Backbone Switching 77 5.1.4 Link Redundancy 78 5.1.5 Multilayer LAN Switching 78 5.1.6 Virtual LANs 78 5.1.7 Transceivers 79 5.1.8 Media Translators 80 5.1.9 Network Adapter Techniques 80 5.1.10 Dynamic Hierarchical Configuration Protocol 82 5.2 Wide Area Networks 83 5.2.1 WAN Technologies 83 5.2.2 Routing Methods 90 5.2.3 Multilayer WAN Switching 96 5.2.4 Design Strategies 101 5.2.5 VPNs 102 5.3 Metropolitan Area Networks 103 5.3.1 Metro Ethernet 104 5.3.2 RPR 106 5.4 Summary and Conclusions 108 References 109 CHAPTER 6 Processing, Load Control, and Internetworking for Continuity 113 6.1 Clusters 113 6.1.1 Cluster Types 114 6.1.2 Cluster Resources 117 6.1.3 Cluster Applications 118 6.1.4 Cluster Design Criteria 118 6.1.5 Cluster Failover 119 6.1.6 Cluster Management 120 6.1.7 Cluster Data 121 6.1.8 Wide Area Clusters 122 6.2 Load Balancing 123 6.2.1 Redirection Methods 125 6.2.2 DNS Redirection 128 6.2.3 SSL Considerations 128 6.2.4 Cookie Redirection 129 6.2.5 Load Balancer Technologies 129 6.2.6 Load Balancer Caveats 131 6.3 Internetworking 132 6.3.1 Web Site Performance Management 132 6.3.2 Web Site Design 135 6.3.3 Web Services 137 Contents ix Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com [...]... discusses some basic network topology and protocol concepts as they relate to continuity to provide background for subsequent discussions on networking Networking technologies (Chapter 5): This chapter focuses on how to leverage different network technologies for continuity, related to local area networks (LANs) and wide area networks (WANs) Processing, load control, and internetworking (Chapter 6):... elsewhere The best disaster-recovery mechanisms are those manifested through network design Network continuity planning means preparing ahead for unexpected disruptions and identifying architectures to ensure that mission-critical network resources remain up and running Using techniques in distributed redundancy, replication, and network management, a self-healing environment is created rivaling even the... Those that do still lack true network continuity and broader business-recovery plans Many plans focus on network data recovery, overlooking the need to protect and recover key applications and servers, which are even more prone to disruption Network continuity planning is a cost-effective, yet underutilized, practice Ultimately, the main benefits of network- continuity planning can be measured in dollars... Affecting Continuity Planning The true case for mission-critical network planning rests on some underlying phenomena that persist in today’s business and operational IT environments: • • • • Most industries rely heavily on computing and networking capabilities, to the point where they have become inseparable from business operations Customer-relationship management (CRM), enterprise resource planning (ERP),... troubled economies As a result, network continuity planning becomes a practice of prioritizing; assigning dollars to those portions of the network that are most mission critical and that can directly affect service delivery If done indiscriminately, network continuity planning can waste time and money, leading to ineffective solutions that produce a false sense of security 1.3 Network Continuity Versus Disaster... adequate network continuity planning, due largely in part to lack of funds and business priority [1] There have been a plethora of studies conveying statistics to the effect But what is of more interest are the findings regarding the causes of inadequate planning, even for those organizations that do have some form of planning in place: • • • Although most businesses are dependent on their IT networks,... once only imaginable can become reality With respect to networking, it is impractical to devise recovery plans for every single event because it is simply impossible to predict them all This is why IT disaster recovery is a subset of a much larger, high-level strategic activity called network continuity planning Network continuity is the ability of a network to continue operations in light of a disruption,... required A network system, no matter how well constructed and maintained, will eventually encounter an error In large complex networks with numerous interoperable systems, errors that plague one system are likely to affect others A disruption in one network can also create problems in other networks, creating a domino effect This has been demonstrated time and again during service provider network outages... Solutions 6.4.2 Caching Benefits and Drawbacks 6.4.3 Content Delivery Networks 6.5 Summary and Conclusions References 137 139 143 144 145 146 149 150 CHAPTER 7 Network Access Continuity 153 7.1 Voice Network Access 7.1.1 PBXs 7.1.2 IP Telephony 7.1.3 Intelligent Voice Response and Voice Mail Systems 7.1.4 Carrier Services 7.2 Data Network Access 7.2.1 Logical Link Access Techniques 7.2.2 Physical Access... environmental disasters Thus, network continuity planning involves creating the ability for networks to withstand such mishaps through properly designed infrastructure, systems, and processes so that operation disruption is minimized Because almost any adverse event or condition can happen, the question then remains as to what things must happen in order to identify and respond to a network disruption The . Data Liotine, Matthew Mission-critical network planning. —(Artech House telecommunications library) 1. Computer networks—Design and construction 2. Business enterprises—Computer networks I. Title 004.6 ISBN. Critical? 1 1.2 Purpose of the Book 2 1.3 Network Continuity Versus Disaster Recovery 2 1.4 The Case for Mission-Critical Planning 4 1.5 Trends Affecting Continuity Planning 5 1.6 Mission Goals and Objectives. Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com Mission-Critical Network Planning Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com For