Network Routing: Algorithms, Protocols, and Architectures (The Morgan Kaufmann Series in Networking)

939 Pages·2007·1.8 MB·English

by  Deepankar Medhi

Network Routing
Algorithms, Protocols, and Architectures
Deepankar Medhi
Karthikeyan Ramasamy
AMSTERDAM•BOSTON•HEIDELBERG•LONDON
NEWYORK•OXFORD•PARIS•SANDIEGO
SANFRANCISCO•SINGAPORE•SYDNEY•TOKYO
MorganKaufmannisanimprintofElsevier
SeniorAcquisitionsEditor RickAdams
AcquisitionsEditor RachelRoumeliotis
PublishingServicesManager GeorgeMorrison
SeniorProductionEditor DawnmarieSimpson
CoverDesign EricDeCicco/YvoRiezebosDesign
CoverImage GettyImages
Composition VTEX
Copyeditor SPi
Proofreader SPi
Indexer SPi
Interiorprinter TheMaple-VailBookManufacturingGroup
Coverprinter PhoenixColor,Inc.
MorganKaufmannPublishersisanimprintofElsevier.
500SansomeStreet,Suite400,SanFrancisco,CA94111
Thisbookisprintedonacid-freepaper.
(cid:2)c2007byElsevierInc.Allrightsreserved.
Designationsusedbycompaniestodistinguishtheirproductsareoftenclaimedastrademarksorregisteredtrademarks.
InallinstancesinwhichMorganKaufmannPublishersisawareofaclaim,theproductnamesappearininitialcapitalor
allcapitalletters.Readers,however,shouldcontacttheappropriatecompaniesformorecompleteinformationregarding
trademarksandregistration.
Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformorbyanymeans—
electronic,mechanical,photocopying,scanning,orotherwise—withoutpriorwrittenpermissionofthepublisher.
PermissionsmaybesoughtdirectlyfromElsevier’sScience&TechnologyRightsDepartmentinOxford,UK:phone:(+44)
1865843830,fax:[phone],E-mail:[e-mail]questonlineviathe
Elsevierhomepage(http://elsevier.com),byselecting
“Support&Contact”then“CopyrightandPermission”andthen“ObtainingPermissions.”
LibraryofCongressCataloging-in-PublicationData
Medhi,Deepankar.
Networkrouting:algorithms,protocols,andarchitectures/DeepankarMedhi,KarthikeyanRamasamy.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN-13:978-0-12-088588-6(hardcover:alk.paper)
ISBN-10:0-12-088588-3(hardcover:alk.paper)1.Computernetworks.2.Routers(Computernetworks)3.Computer
networkarchitectures.I.Ramasamy,Karthikeyan,1967-II.Title.
TK5105.5.M4252007
004.6–dc22
2006028700
ISBN13:978-0-12-088588-6
ISBN10:0-12-088588-3
ForinformationonallMorganKaufmannpublications,
visitourWebsiteatwww.mkp.comorwww.books.elsevier.com
PrintedintheUnitedStatesofAmerica
07080910 54321
Contents
Foreword xxiii
Preface xxv
AbouttheAuthors xxxi
Part I: Network Routing: Basics and Foundations 1
1 NetworkingandNetwork Routing:AnIntroduction 2
1.1 AddressingandInternetService:AnOverview 4
1.2 NetworkRouting:AnOverview 5
1.3 IPAddressing 7
1.3.1 ClassfulAddressingScheme 8
1.3.2 Subnetting/Netmask 9
1.3.3 ClasslessInterdomainRouting 10
1.4 OnArchitectures 11
1.5 ServiceArchitecture 12
1.6 ProtocolStackArchitecture 13
1.6.1 OSIReferenceModel 13
1.6.2 IPProtocolStackArchitecture 14
1.7 RouterArchitecture 19
1.8 NetworkTopologyArchitecture 20
1.9 NetworkManagementArchitecture 21
1.10 PublicSwitchedTelephoneNetwork 21
1.11 CommunicationTechnologies 22
1.12 StandardsCommittees 24
1.12.1 InternationalTelecommunicationUnion 24
1.12.2 InternetEngineeringTaskForce 25
1.12.3 MFAForum 25
1.13 LastTwoBits 25
1.13.1 Type-Length-Value 25
1.13.2 NetworkProtocolAnalyzer 26
viii Contents
1.14 Summary 26
FurtherLookup 27
Exercises 27
2 RoutingAlgorithms:ShortestPathandWidestPath 30
2.1 Background 31
2.2 Bellman–FordAlgorithmandtheDistanceVectorApproach 33
2.2.1 CentralizedView:Bellman–FordAlgorithm 33
2.2.2 DistributedView:ADistanceVectorApproach 36
2.3 Dijkstra’sAlgorithm 38
2.3.1 CentralizedApproach 38
2.3.2 DistributedApproach 40
2.4 ComparisonoftheBellman–FordAlgorithmandDijkstra’sAlgorithm 42
2.5 ShortestPathComputationwithCandidatePathCaching 43
2.6 WidestPathComputationwithCandidatePathCaching 45
2.7 WidestPathAlgorithm 47
2.7.1 Dijkstra-BasedApproach 47
2.7.2 Bellman–Ford-BasedApproach 49
2.8 k-ShortestPathsAlgorithm 49
2.9 Summary 51
FurtherLookup 53
Exercises 53
3 RoutingProtocols: Framework andPrinciples 56
3.1 RoutingProtocol,RoutingAlgorithm,andRoutingTable 57
3.2 RoutingInformationRepresentationandProtocolMessages 59
3.3 DistanceVectorRoutingProtocol 60
3.3.1 ConceptualFrameworkandIllustration 60
3.3.2 WhyTimersMatter 66
3.3.3 Solutions 70
3.3.4 CanWeAvoidLoops? 74
3.3.5 DistanceVectorProtocolBasedonDiffusingComputationwith
CoordinatedUpdate 74
3.4 LinkStateRoutingProtocol 82
3.4.1 LinkStateProtocol:In-BandHop-by-HopDisseminations 83
3.4.2 LinkStateProtocol:In-BandBasedonEnd-to-EndSession 91
3.4.3 RouteComputation 92
3.5 PathVectorRoutingProtocol 93
3.5.1 BasicPrinciple 93
3.5.2 PathVectorwithPathCaching 97
3.6 LinkCost 102
3.6.1 ARPANETRoutingMetrics 102
3.6.2 OtherMetrics 103
Contents ix
3.7 Summary 104
FurtherLookup 105
Exercises 105
4 Network FlowModeling 108
4.1 Terminologies 109
4.2 Single-CommodityNetworkFlow 110
4.2.1 AThree-NodeIllustration 110
4.2.2 FormalDescriptionandMinimumCostRoutingObjective 111
4.2.3 VariationinObjective:LoadBalancing 114
4.2.4 VariationinObjective:AverageDelay 116
4.2.5 SummaryandApplicability 117
4.3 MulticommodityNetworkFlow:Three-NodeExample 118
4.3.1 MinimumCostRoutingCase 118
4.3.2 LoadBalancing 123
4.3.3 AverageDelay 125
4.4 MulticommodityNetworkFlowProblem:GeneralFormulation 128
4.4.1 BackgroundonNotation 129
4.4.2 Link-PathFormulation 130
4.4.3 Node-LinkFormulation 135
4.5 MulticommodityNetworkFlowProblem:Non-SplittableFlow 137
4.6 Summary 138
FurtherLookup 139
Exercises 139
Part II: Routing in IP Networks 141
5 IPRoutingandDistanceVectorProtocolFamily 142
5.1 Routers,Networks,andRoutingInformation:SomeBasics 143
5.1.1 RoutingTable 143
5.1.2 CommunicationofRoutingInformation 146
5.2 StaticRoutes 146
5.3 RoutingInformationProtocol,Version1(RIPv1) 147
5.3.1 CommunicationandMessageFormat 147
5.3.2 GeneralOperation 149
5.3.3 IsRIPv1GoodtoUse? 150
5.4 RoutingInformationProtocol,Version2(RIPv2) 150
5.5 InteriorGatewayRoutingProtocol(IGRP) 153
5.5.1 PacketFormat 153
5.5.2 ComputingCompositeMetric 154
5.6 EnhancedInteriorGatewayRoutingProtocol(EIGRP) 157
5.6.1 PacketFormat 157
5.7 RouteRedistribution 160
5.8 Summary 161
x Contents
FurtherLookup 163
Exercises 164
6 OSPFandIntegrated IS-IS 166
6.1 FromaProtocolFamilytoanInstanceofaProtocol 167
6.2 OSPF:ProtocolFeatures 168
6.2.1 NetworkHierarchy 168
6.2.2 RouterClassification 168
6.2.3 NetworkTypes 169
6.2.4 Flooding 170
6.2.5 LinkStateAdvertisementTypes 171
6.2.6 Subprotocols 171
6.2.7 RoutingComputationandEqual-CostMultipath 172
6.2.8 AdditionalFeatures 176
6.3 OSPFPacketFormat 177
6.4 ExamplesofRouterLSAsandNetworkLSAs 183
6.5 IntegratedIS-IS 185
6.5.1 KeyFeatures 186
6.6 SimilaritiesandDifferencesBetweenIS-ISandOSPF 189
6.7 Summary 191
FurtherLookup 191
Exercises 191
7 IPTraffic Engineering 194
7.1 Traffic,Stochasticity,Delay,andUtilization 195
7.1.1 WhatIsIPNetworkTraffic? 195
7.1.2 TrafficandPerformanceMeasures 195
7.1.3 CharacterizingTraffic 196
7.1.4 AverageDelayinaSingleLinkSystem 197
7.1.5 NonstationarityofTraffic 199
7.2 Applications’View 200
7.2.1 TCPThroughputandPossibleBottlenecks 200
7.2.2 Bandwidth-DelayProduct 201
7.2.3 RouterBufferSize 202
7.3 TrafficEngineering:AnArchitecturalFramework 203
7.4 TrafficEngineering:AFour-NodeIllustration 204
7.4.1 NetworkFlowOptimization 204
7.4.2 ShortestPathRoutingandNetworkFlow 206
7.5 LinkWeightDeterminationProblem:PreliminaryDiscussion 211
7.6 DualityoftheMCNFProblem 213
7.6.1 IllustrationofDualityThroughaThree-NodeNetwork 213
7.6.2 GeneralCase:MinimumCostRouting 215
7.6.3 MinimizationofMaximumLinkUtilization 219
7.6.4 ACompositeObjectiveFunction 221
7.6.5 MinimizationofAverageDelay 222
Contents xi
7.7 IllustrationofLinkWeightDeterminationThroughDuality 226
7.7.1 CaseStudy:I 226
7.7.2 CaseStudy:II 231
7.8 LinkWeightDetermination:LargeNetworks 232
7.9 Summary 234
FurtherLookup 235
Exercises 235
8 BGP 238
8.1 BGP:ABriefOverview 239
8.2 BGP:BasicTerminology 242
8.3 BGPOperations 243
8.3.1 MessageOperations 243
8.3.2 BGPTimers 244
8.4 BGPConfigurationInitialization 245
8.5 TwoFacesofBGP:ExternalBGPandInternalBGP 247
8.6 PathAttributes 250
8.7 BGPDecisionProcess 254
8.7.1 BGPPathSelectionProcess 254
8.7.2 RouteAggregationandDissemination 256
8.7.3 Recap 257
8.8 InternalBGPScalability 257
8.8.1 RouteReflectionApproach 258
8.8.2 ConfederationApproach 261
8.9 RouteFlapDampening 262
8.10 BGPAdditionalFeatures 265
8.10.1 Communities 265
8.10.2 MultiprotocolExtension 265
8.11 FiniteStateMachineofaBGPConnection 266
8.12 ProtocolMessageFormat 270
8.12.1 CommonHeader 270
8.12.2 MessageType:OPEN 270
8.12.3 MessageType:UPDATE 272
8.12.4 MessageType:NOTIFICATION 274
8.12.5 MessageType:KEEPALIVE 274
8.12.6 MessageType:ROUTE–REFRESH 274
8.12.7 PathAttributeinUPDATEmessage 276
8.13 Summary 277
FurtherLookup 278
Exercises 278
9 InternetRoutingArchitectures 280
9.1 InternetRoutingEvolution 281
9.2 AddressingandRouting:Illustrations 283
9.2.1 RoutingPacket:ScenarioA 285
xii Contents
9.2.2 RoutingPacket:ScenarioB 286
9.2.3 RoutingPacket:ScenarioC 288
9.3 CurrentArchitecturalViewoftheInternet 290
9.3.1 CustomersandProviders,PeeringandTiering,andExchangePoints 291
9.3.2 ARepresentativeArchitecture 294
9.3.3 CustomerTrafficRouting:AGeographicPerspective 297
9.3.4 SizeandGrowth 298
9.4 AllocationofIPPrefixesandASNumber 301
9.5 Policy-BasedRouting 304
9.5.1 BGPWedgies 306
9.6 PointofPresence 307
9.7 TrafficEngineeringImplications 309
9.8 InternetRoutingInstability 311
9.9 Summary 312
FurtherLookup 312
Exercises 313
Part III: Routing in the PSTN 315
10 HierarchicalandDynamic CallRoutingintheTelephoneNetwork 316
10.1 HierarchicalRouting 317
10.1.1 BasicIdea 317
10.1.2 ASimpleIllustration 318
10.1.3 OverallHierarchicalRoutingArchitecture 320
10.1.4 TelephoneServiceProvidersandTelephoneNetworkArchitecture 321
10.2 TheRoadtoDynamicRouting 322
10.2.1 LimitationofHierarchicalRouting 322
10.2.2 HistoricalPerspective 323
10.2.3 CallControlandCrankback 325
10.2.4 TrunkReservation 326
10.2.5 WhereDoesDynamicRoutingFitwithHierarchicalRouting? 326
10.2.6 MixingofOCCandPCC 327
10.2.7 Summary 327
10.3 DynamicNonhierarchicalRouting 328
10.4 DynamicallyControlledRouting 330
10.5 DynamicAlternateRouting 333
10.6 Real-TimeNetworkRouting 334
10.7 ClassificationofDynamicCallRoutingSchemes 336
10.8 MaximumAllowableResidualCapacityRouting 337
10.9 DynamicRoutingandItsRelationtoOtherRouting 339
10.9.1 DynamicRoutingandLinkStateProtocol 339
10.9.2 PathSelectioninDynamicRoutinginTelephoneNetworksandIP
Routing 339
10.9.3 RelationtoConstraint-BasedRouting 340
Contents xiii
10.10 Recap 340
FurtherLookup 341
Exercises 342
11 Traffic EngineeringintheVoiceTelephoneNetwork 344
11.1 WhyTrafficEngineering? 345
11.2 TrafficLoadandBlocking 346
11.2.1 ComputingErlang-BLossFormula 349
11.3 Grade-of-ServiceandTrunkOccupancy 350
11.4 Centi-CallSecondsandDeterminingOfferedLoad 352
11.5 EconomicCCSMethod 354
11.6 NetworkControlsforTrafficEngineering 356
11.6.1 GuidelinesonDetectionofCongestion 357
11.6.2 ExamplesofControls 357
11.6.3 CommunicationofCongestionControlInformation 361
11.6.4 CongestionManifestation 361
11.7 State-DependentCallRouting 362
11.8 AnalysisofDynamicRouting 363
11.8.1 Three-NodeNetwork 364
11.8.2 N-NodeSymmetricNetwork 366
11.8.3 N-NodeSymmetricNetworkwithTrunkReservation 367
11.8.4 IllustrationWithoutandwithTrunkReservation 369
11.9 Summary 371
FurtherLookup 371
Exercises 372
12 SS7:SignalingNetwork forTelephony 374
12.1 WhySS7? 375
12.2 SS7NetworkTopology 375
12.2.1 NodeTypes 376
12.2.2 SS7Links 376
12.3 RoutingintheSS7Network 378
12.4 PointCodes:AddressinginSS7 380
12.4.1 NorthAmericanPointCode 380
12.4.2 ITUPointCode 381
12.5 PointCodeUsage 382
12.5.1 AddressAssignment 382
12.5.2 RelationshipBetweenaTelephoneSwitchandanSSP 382
12.5.3 InterworkingofSS7NetworkswithDifferentAddressingSchemes 383
12.6 SS7ProtocolStack 384
12.6.1 Lower-LayerProtocols:MTP1,MTP2,andMTP3 384
12.6.2 Upper-LayerProtocols 388
12.7 SS7NetworkManagement 388
12.8 ISUPandCallProcessing 389
12.8.1 Called/CallingPartyNumberFormat 395
xiv Contents
12.9 ISUPMessagesandTrunkManagement 396
12.10 ISUPMessagesandDynamicCallRouting 396
12.10.1 Functionalities 397
12.10.2 Illustration 398
12.11 TransactionServices 400
12.11.1 SCCP:SignalingConnectionControlPart 400
12.11.2 TCAP:TransactionCapabilitiesApplicationPart 401
12.12 SS7LinkTrafficEngineering 402
12.12.1 SS7NetworkPerformanceRequirements 403
12.13 Summary 404
FurtherLookup 404
Exercises 405
13 PublicSwitchedTelephone Network: Architecture andRouting 406
13.1 GlobalTelephoneAddressing 407
13.1.1 NationalNumberingPlan 409
13.1.2 DialingPlan 412
13.2 SettingUpaBasicTelephoneCallandItsSteps 415
13.3 DigitAnalysisversusTranslation 417
13.4 RoutingDecisionforaDialedCall 417
13.5 CallRouting:SingleNationalProviderEnvironment 417
13.5.1 HandlingDialedNumbers 418
13.5.2 IllustrationofCallRouting 419
13.5.3 SomeObservations 423
13.6 CallRouting:MultipleLong-DistanceProviderCase 424
13.6.1 IllustrationofCallRouting 427
13.6.2 ImpactonRouting 430
13.7 Multiple-ProviderEnvironment:MultipleLocalExchangeCarriers 432
13.8 RoutingDecisionatanIntermediateTDMSwitch 433
13.9 NumberPortability 434
13.9.1 Introduction 434
13.9.2 PortabilityClassification 435
13.10 NongeographicorToll-FreeNumberPortability 436
13.10.1 800-NumberManagementArchitecture 437
13.10.2 MessageandCallRouting 438
13.11 Fixed/MobileNumberPortability 439
13.11.1 PortabilityArchitecture 439
13.11.2 RoutingSchemes 442
13.11.3 ComparisonofRoutingSchemes 446
13.11.4 ImpactonIAMMessage 446
13.11.5 NumberPortabilityImplementation 448
13.11.6 RoutinginthePresenceofTransitNetwork 448
13.12 Multiple-ProviderEnvironmentwithLocalNumberPortability 451