




已閱讀5頁,還剩5頁未讀, 繼續(xù)免費(fèi)閱讀
版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請進(jìn)行舉報(bào)或認(rèn)領(lǐng)
文檔簡介
173CHAPTER8TRAFCMANAGEMENTANDCONTROL81INTRODUCTIONCOMMUNICATIONSTRAFCMANAGEMENTANDCONTROLISINMANYWAYSSIMILARTOMANAGINGANDCONTROLLINGVEHICULARTRAFCINALARGECITYTHINKOFTHEMAINAVENUESASARTERIALTRAFCBEARINGLINKSTHATBRINGTRAFCVEHICLESANDPEDESTRIANSTOINTERSECTIONSWITHTRAFCLIGHTSINTHISCASE,TRAFCLIGHTSMAYBECONSIDEREDTHEEQUIVALENTOFTRAFCSWITCHINGNODES,WHEREASVEHICLESANDPEDESTRIANSARETHEEQUIVALENTOFPACKETSOFINFORMATIONINCOMMUNICATIONSIFTRAFCLIGHTSAREWELLSYNCHRONIZEDANDTHEYTURNGREENANDREDFORTHECORRECTAMOUNTOFTIMEACCORDINGTOVOLUMEOFVEHICLESORPEDESTRIANSATTHEQUEUES,THENTRAFCFRUSTRATINGJAMSAREELIMINATEDORATLEASTMINIMIZEDBUTHOWDOWECONTROLALLLIGHTSTOACCOMPLISHTHISCURRENTLY,INLARGECITIES,INTELLIGENTCAMERASMONITORTHEOWOFCARSANDTHEQUEUESATTHEINTERSECTIONS,ANDBASEDONATRAFCALGORITHM,LIGHTSCONTROLTHEOWTOMINIMIZEATLEASTINTHEORYCONGESTIONHOWEVER,CURRENTLYTHISREQUIRESHUMANINTERVENTION,ANDITISNOTCOMPLETELYAUTOMATICINFACT,THESCENARIOOFCOMPUTERCONTROLLINGTRAFCLIGHTSHASINSPIREDAHOLLYWOODMOVIETHISCITYTRAFCPARADIGM,ASCOMPLEXASITMAYSEEM,ISMUCHSIMPLERTHANACOMMUNICATIONSSWITCHINGNODE,WHERETHEREAREMANYINPUTANDOUTPUTBERS,EACHBERHASMANYOPTICALCHANNELS,ANDEACHOPTICALCHANNELCARRIESASIGNALEG,OC48,WHICHISTHEMULTIPLEXOFMANYTRIBUTARIESINTHISSCENARIO,SOMESIGNALSMAYNEEDTOBESWITCHEDINTACT,WHEREASSOMEOTHERSNEEDTOBEDEMULTIPLEXEDSINCEDIFFERENTTRIBUTARIESNEEDTOBESWITCHEDTODIFFERENTOUTPUTPORTSMOREOVER,THESIGNALMAYCONTAINSYNCHRONOUSPAYLOADSVOICE,VIDEOANDASYNCHRONOUSIP,ETHERNET,ANDOTHERDATASPECICTHATIS,THEREAREDIFFERENTPROTOCOLSTOBEEXECUTEDANDDIFFERENTREQUIREMENTSSEEFIGS419AND426THUS,SOMEPAYLOADSNEEDTOBESWITCHEDWITHOUTDELAY,WHEREASSOMEOTHERSMAYBETEMPORARILYBUFFEREDWITHSUCHCOMPLEXITY,THECITYTRAFCCONTROLPROBLEMSUDDENLYSEEMSVERYSIMPLECOMPAREDWITHTHECOMMUNICATIONSTRAFCCONTROLBASEDONTHISCOMMUNICATIONSPARADIGM,INDWDMOPTICALNETWORKS,THEREARETWOMAJORMANAGEMENTTYPESONEISCONCERNEDWITHTHEWAVELENGTHMANAGEMENTACROSSTHENETWORKANDTHEOTHERWITHCLIENTBANDWIDTHMANAGEMENTINTHEFOLLOWING,WEASSUMETHATCONTROLMESSAGESTHATAREREQUIREDFORBANDWIDTHMANAGEMENTANDCONNECTIVITYESTABLISHMENTAREACCOMPLISHEDUSINGSPECICMESSAGESANDALGORITHMSBASEDONONEOFTHESEVERALWELLKNOWNMETHODSDISTRIBUTEDORCENTRALIZEDCONTROLANDINCHANNELOROUTOFCHANNELMESSAGESCENTRALIZEDCONTROLIMPLIESTHATALLNODESSENDCONGURATIONANDSTATEMESSAGESTOACENTRALIZEDSYSTEMTHATOVERSEESTHEOPERATIONANDCONNECTIVITYESTABLISHMENTACROSSTHEOVERALLNETWORK,FIG81ALTHOUGHCENTRALIZEDCONTROLISEFCIENT,ANAGREEMENTMUSTEXISTAMONGALLNETWORKOPERATORSIFDIFFERENTONCOMMONNETWORKPARAMETERS,PERFORMANCEOBJECTIVES,ANDPROTOCOLLANGUAGESDISTRIBUTEDCONTROLIMPLIESTHATALLNODESINTHEOVERALLNETWORKPARTAKEINTHENETWORKCONTROL,FIG82THISISACCOMPLISHEDWITHEXTENSIVEPROTOCOLSTONDTHEBESTROUTEINTHENETWORKASWELLSVKARTALOPOULOS,NEXTGENERATIONINTELLIGENTOPTICALNETWORKS,CSPRINGER20081748TRAFCMANAGEMENTANDCONTROLNMSEMS/NMSSTANDARDINTERFACEEMSAEMSBEMSNVENDORSPECIFICORSTANDARDINTERFACENENENENENENENENENEMULTIVENDORNETWORKFIG81CENTRALIZEDCONTROLOFAMULTIVENDORNETWORKENVIRONMENTCONSISTSOFINTERCONNECTEDNETWORKELEMENTSNETHATCOMPRISENETWORKDOMAINS,ANDEACHDOMAINISCONNECTEDWITHTHENETWORKMANAGEMENTSYSTEMNMSVIAELEMENTMANAGEMENTSYSTEMSEMSASTOMANAGETHEHEALTHOFTHENETWORKANDTRAFCEFCIENCYFOREXAMPLE,THEHOPBYHOPROUTEDISCOVERYANDOODINGTHENETWORKARETWOWELLKNOWNALGORITHMS1BECAUSEDISTRIBUTEDCONTROLUSESEXTENSIVEPROTOCOLSANDALGORITHMS,ANAGREEMENTMUSTEXISTAMONGALLNETWORKOPERATORSIFDIFFERENTONCOMMONNETWORKINTERFACEPROTOCOLSANDPERFORMANCEOBJECTIVESINCHANNELMESSAGESAREMESSAGESEMBEDDEDINTHEOVERHEADOFTHESAMECHANNELORPACKETTHATTRANSPORTSCLIENTDATAFOREXAMPLE,INSONET/SDH,SPECICCONTROLMESSAGESFORERRORCONTROLANDPROTECTIONTOSWITCHINGAREINCLUDEDINTHEOVERHEADCONVERSELY,OUTOFCHANNELMESSAGESAREMESSAGESTHATUSESPECICALLYALLOCATEDCHANNELSORPACKETSFOREXAMPLE,THISISTHECASEINATMWHICHUSESSPECICATMCELLSFORCALLADMISSIONCONTROLANDSERVICELEVELAGREEMENTNEGOTIATION,ANDINTHEOTNCASE,ITUSESASEPARATESUPERVISORYCHANNEL,FIG83NETWORKNCISUBNETWORKDOMAINONNINCIONNIOPTNETTONETINTERFACENCINETWORKTOCLIENTINTERFACEFIG82INDISTRIBUTEDCONTROL,ALLNODESPARTAKEINTHEDISCOVERYOFTHEBESTOPTICALROUTEACROSSTHEOVERALLNETWORK,WHICHMAYCONSISTOFSUBNETWORKSORDOMAINS83WAVELENGTHMANAGEMENTFIG83INOTN,OVERHEADINFORMATIONABOUTSECTION,PATH,ANDTANDEMCONNECTIONISTRANSPORTEDWITHANOUTOF175OCHSECTIONOCHTCOPTICALSUPERVISORYCHANNELOSCOCHPATHOCHPAYLOADTRANSPORTEDOVEROTMNTCTANDEMCONNECTIONOCHOVERHEADTRANSPORTEDOVEROSC82CLIENTBANDWIDTHMANAGEMENTCLIENTBANDWIDTHMANAGEMENTISAFUNCTIONTHATISREQUIREDBYALLTYPESOFCOMMUNICATIONSYSTEMSANDNETWORKS,VOICEORDATA,SMALLORLARGETHISFUNCTIONMUSTASSURETHATCLIENTSDATAISDELIVEREDRELIABLY,SECURELY,TIMELY,ANDWITHTHEAGREEDQUALITYOFSERVICE2,REGARDLESSOFTHEMETHODITISTRANSPORTED,NAMELY,BYMEANSOFTRIBUTARYORCONTAINERUNITSASINSYNCHRONOUSTRAFC,ORDIRECTLYMAPPEDORBULKLLEDINTHESYNCHRONOUSPAYLOADSEEFIG210,ORPACKETIZEDANDTRANSPORTEDBYMEANSOFADAPTATIONCLIENTBANDWIDTHMANAGEMENTHASTWOOBJECTIVES1DELIVERTHECLIENTSBANDWIDTHACCORDINGTOSERVICELEVELAGREEMENTANDQUALITYOFSERVICEAND2INCREASETHENETWORKBANDWIDTHEFCIENCYBYLLINGTHEPAYLOADENVELOPEORTHENETWORKBANDWIDTHCAPACITYWITHTHECLIENTDATAASMUCHASPOSSIBLEHOWEVER,ASTRAFCBECOMESMOREELASTIC3,ASTHEAGGREGATEBANDWIDTHDEMANDINCREASES,ASFAULTSANDSEVEREDEGRADATIONSOCCURINNODES,ONBERLINKS,ANDINOPTICALCHANNELS4,TRAFCMANAGEMENTBECOMESMORECHALLENGING83WAVELENGTHMANAGEMENTINMODERNDWDMSYSTEMS,EACHWAVELENGTHOFTHEITUTGRIDISUSEDASASEPARATEOPTICALPATH,ALSOCALLEDALIGHTPATH,WHICHLIKEAHIGHWAYCARRIESMANYCLIENTSIGNALSESTABLISHINGENDTOENDCONNECTIVITYCURRENTLY,THEREARETWOFUNDAMENTALLYDIFFERENTMETHODSFORESTABLISHINGLIGHTWAVECONNECTIVITYTHERSTMETHODCONSIDERSAPATHFORWHICHTHESAMEWAVELENGTHOVERTHEENTIREENDTOENDPATHISASSIGNEDEVENIFTHELIGHTPATHISACROSSSEVERALSUBNETWORKS,EACHMANAGEDBYDIFFERENTNETWORKOPERATORTHISCASEISKNOWNASSINGLEWAVELENGTHPATHCONNECTIVITY,FIG84ALTHOUGHATRSTGLANCETHISMETHODMAYSEEMSIMPLISTIC,INAMULTINODENETWORK,ITISCOMPLEX,ANDITMAYRESULTINWAVELENGTHCONTENTIONORBLOCKINGANDTHUSNETWORKINEFCIENCYTHESECONDMETHODCONSIDERSDIFFERENTWAVELENGTHSTHATARECONCATENATEDOVERACOMPLETEPATHTHISMETHODISNETWORKB2B1SUBNETWORKFIG84AMESHNETWORKMAYESTABLISHCONNECTIVITYDOMAINUSINGTHESAMEWAVELENGTHENDTOENDORMULTIPLECONCATENATEDWAVELENGTHSA1A21768TRAFCMANAGEMENTANDCONTROLKNOWNASMULTIWAVELENGTHPATHCONNECTIVITYTHELATTERMETHODREQUIRESEITHERWAVELENGTHCONVERTERSATEACHNODEORNODESTHATAREOPTICALELECTRICALOPTICALOEOTHISMETHODHASTHEADDEDADVANTAGEOFUTILIZINGDIFFERENTWAVELENGTHSOFTHEITUTGRIDONTHELINKSTHATMAKEUPTHEPATHANDTHUSITINCREASESWAVELENGTHUTILIZATIONANDEFCIENCYHOWEVER,THISMETHODADDSTONODEDESIGNCOMPLEXITYANDCOSTOFCOMPONENTSSUBSTANTIALLY,ANDTHUSTOFAILUREMODES,PROVISIONING,ANDMAINTENANCEWAVELENGTHMANAGEMENTFORTHESINGLEWAVELENGTHPATHCONNECTIVITYMETHODISSIMPLERALTHOUGHLIMITEDANDBANDWIDTHINEFCIENTTHEREASONISTHATTHENETWORKMAYBEUNABLETONDTHESAMEWAVELENGTHFROMSOURCETODESTINATIONFORALLPOSSIBLEROUTESLEADINGTOPOTENTIALWAVELENGTHBLOCKINGFOREXAMPLE,IFWECONSIDERAMESHDWDMNETWORK,THEBLOCKINGPROBABILITYISAFUNCTIONOFTOPOLOGY,NUMBEROFBERSPERNODEANDNUMBEROFWAVELENGTHSOPTICALCHANNELSPERBER,ANDALSONUMBEROFDROPPEDANDADDEDCHANNELSATEACHNODEWEASSUMETHATNODESINAMESHNETWORKAREALSOOPTICALADDDROPMULTIPLEXINGNODESOADMTHUS,ASTHENUMBEROFBERSPERNODEANDWAVELENGTHSPERBERINCREASE,THEPROBABILITYFORBLOCKINGDECREASESTHEKEYOBJECTIVEINTHISCASEISBANDWIDTHEFCIENCY5WAVELENGTHMANAGEMENTFORTHEMULTIWAVELENGTHPATHCONNECTIVITYMETHODISMORECOMPLEXALTHOUGHMOREBANDWIDTHEFCIENTANDBECAUSEOFTHEADDEDHARDWARECOMPLEXITYADDEDWAVELENGTHCONVERTERS,ITISCOSTLIERINTHISCASE,IFWECONSIDERAMESHDWDMNETWORKWITHWAVELENGTHCONVERTERSINEACHNODE,THEBLOCKINGPROBABILITYISAFUNCTIONOFTOPOLOGY,NUMBEROFBERSPERNODEANDNUMBEROFWAVELENGTHSOPTICALCHANNELSPERBER,NUMBEROFDROPPEDANDADDEDCHANNELSATEACHNODE,ANDALSONUMBEROFCONVERTERSINEACHNODETHUS,ASTHENUMBEROFBERSPERNODEANDWAVELENGTHSPERBERINCREASES,THEREQUIREDNUMBEROFCONVERTERSINEACHNODEINCREASES,THEPROBABILITYFORBLOCKINGISALMOSTELIMINATEDALTHOUGHTHECOSTOFTHENETWORKANDWAVELENGTHMANAGEMENTINCREASESDRAMATICALLYASARESULT,THEOBJECTIVEINTHISCASEISTOBALANCEBANDWIDTHEFCIENCYANDOPTIMIZECOSTAHYBRIDMETHODMAYBEUSEDTOACCOMPLISHTHISALLOCATEANUMBEROFWAVELENGTHSTHATPROVIDESINGLEWAVELENGTHCONNECTIVITYOVERSELECTEDPATHSANDALLOCATETHEREMAININGWAVELENGTHSFORTHEMULTIWAVELENGTHCONNECTIVITYPATHMETHODTHISMETHODELIMINATESSEVERALWAVELENGTHCONVERTERS,ANDITSIMPLIESNODEDESIGNANDWAVELENGTHMANAGEMENTACONSEQUENCETHATALSONEEDSTOBEADDRESSEDISPROTECTIONSTRATEGY,ATTHEBERLEVELASWELLASATTHEWAVELENGTHLEVELDUETOSEVEREDEGRADATIONORCOMPONENTHARDFAILUREPROTECTIONMAYBESIMPLEORCOMPLEX,DEPENDINGONTHEADAPTEDPROTECTIONSTRATEGY,11,11,1N,ANDSOONINDWDM,ANOTHERISSUEHASAROSE,NAMELYWAVELENGTHCOLLISIONINTRADITIONALSINGLEWAVELENGTHNETWORKS,WAVELENGTHCOLLISIONHASNOTBEENANISSUESINCETHEOPTICALCHANNELWASONLYONEAT1,310ORAT1,550NMTHUS,MOVINGTHISCHANNELFROMONEBERTOANOTHER,ITWASASTRAIGHTFORWARDOPERATION,ASLONGASAPROTECTIONBERWASAVAILABLEINDWDM,WHEREONESYSTEMINONEDOMAINISINTERCONNECTEDWITHASYSTEMINANOTHERDOMAINWHEREDOMAINSMAYBEOPERATEDBYDIFFERENTNETWORKPROVIDERS,WAVELENGTHCOLLISIONMAYOCCUR,FIG85,WAVELENGTHCONVERSIONISNEEDEDANDALSOWAVELENGTHMANAGEMENTOVERTHECOMPLETEENDTOENDPATHHERE,WAVELENGTHCOLLISIONISDENEDASTHEACTIONBYWHICHONEOPTICALCHANNELASSOCIATEDWITHAPARTICULARWAVELENGTHOVERANETWORKB2B1SUBNETWORKFIG85SOMESAMEWAVELENGTHLIGHTPATHSDOMAINMAYOVERLAPOVERONEORMORELINKSCAUSINGWAVELENGTHCOLLISIONA1A284TRAFCMANAGEMENT177LINKISSWITCHEDFROMLINKATOLINKB,WHEREINLINKBTHESAMEWAVELENGTHISALREADYINUSEFORADIFFERENTPATHTHISDENITIONISEXTENDABLETOMORETHANONEWAVELENGTHASARESULT,ASUBSTANTIALEFFORTHASBEENSPENTTODETERMINETHEBLOCKINGPROBABILITYFORDIFFERENTNETWORKTOPOLOGIES,NODECOMPLEXITIES,ANDTRAFCCHARACTERISTICSANDALSOUNDERSTATICAND/ORDYNAMICCONDITIONSINTHISPURSUE,SEVERALALGORITHMSWEREDEVELOPEDTOESTABLISHTHERULESTHATOPTIMIZEWAVELENGTHASSIGNMENTPROCEDURESANDTHUSTRAFCROUTINGANDNETWORKTHROUGHPUT612831PATHSWITHROADMSWDMOPTICALPOINTTOPOINT,MESHORRINGNETWORKSHAVENODESTHATARECAPABLEOFDROPINGANDADDINGWAVELENGTHS,HENCEKNOWNASOPTICALADDDROPMULTIPLEXINGNODESOADMTHEADDED/DROPPEDWAVELENGTHSCARRYTRAFCTOBEDELIVEREDTOCUSTOMERSATTHELOCATIONOFTHEOADMCURRENTLY,THISISACCOMPLISHEDBYDESIGNATINGAPRIORIWHICHWAVELENGTHSOFTHEGRIDISTOBEDROPPEDASWELLASTHENUMBEROFWAVELENGTHSDEPENDINGONAPPLICATION,FROM1TO4,THISISKNOWNASXEDOADMCONGURABILITYTHENEXTGENERATIONINTELLIGENTNETWORKHOWEVERNEEDSTOBEABLETODROPANDADDEXIBLETRAFC,ANDTHUSOADMNODESNEEDTOBERECONGURABLEASDESCRIBEDIN13THATIS,OADMNODESMUSTBEABLETOBEPROGRAMEDEITHERLOCALLYORREMOTELYANDBEABLETODROPANDADDFROM1TONWAVELENGTHS,ASNEEDARISESSUCHNODESAREKNOWNASRECONGURABLEOADMSROADMHOWEVER,BECAUSEOFTHEDYNAMICNATUREOFRECONGURABILITY,ROADMSNEEDTOBEFAST,RELIABLE,ANDVERIABLEWESHOULDALSOPOINTOUTTHATMESHNETWORKSWITHROADMSADDANADDITIONALLEVELOFCOMPLEXITYONTHEPATHORROUTENDINGALGORITHMSBECAUSEWAVELENGTHSTHATAREAVAILABLEFORESTABLISHINGCONNECTIVITYMAYHAVETOBEUSEDBYROADMSANDTHUSTHENUMBEROFWAVELENGTHSFORENDTOENDCONNECTIVITYNEEDTOBERECALCULATEDADDITIONALLY,RECONGURABILITYADDSTONODEDESIGNCOMPLEXITYBECAUSECERTAINRECONGURABLEORREASSIGNEDWAVELENGTHSAREDROPPEDANDADDEDINSTEADOFCONTINUINGTHROUGHORVICEVERSATHUS,THISMAYREQUIREOPTICALPOWERBUDGETRECALCULATIONANDWAVELENGTHEQUALIZATIONANDDISPERSIONCOMPENSATIONANOTHERNODECOMPLEXITYISADDEDIFATTHEROADMCERTAINWAVELENGTHSAREREASSIGNEDTOBEDROPPEDANDADDEDINORDERTOCARRYMULTIPLEXEDTRAFCSUCHASSONET/SDH,INWHICHSOMEVTSNEEDTOPASSTHROUGHHOWEVER,THISISSIMPLIEDIFTRAFCISPACKETIZEDOPTIMIZINGTRAFCEFCIENCYFORDIFFERENTTRAFCTYPESISTHESUBJECTOFCURRENTRESEARCH84TRAFCMANAGEMENTTRAFCMANAGEMENTISRELATEDTOCLIENTTRAFCANDTHEREFORE,ALTHOUGHRELATEDTOBANDWIDTHMANAGEMENT,HASMORESPECICTASKSTOPERFORMFOREXAMPLE,ALTHOUGHBANDWIDTHMANAGEMENTADDRESSESTHEDISTRIBUTIONOFTRAFCEVENLYOVERNETWORK,ALSOKNOWNASBANDWIDTHBALANCING,TRAFCMANAGEMENTISMORECONCERNEDWITHCLIENTTRAFCSOTHATITMEETSTHEEXPECTEDQUALITYOFSERVICE,EXPECTEDREALTIMEDELIVERY,ANDALSOCLIENTBANDWIDTHONDEMANDTRAFCMANAGEMENTASSURESTHATINCOMINGTRAFCISMONITORED,ITISPROPERLYCONNECTED,ANDITSQUALITYLEVELISMAINTAINEDTHISISACCOMPLISHEDBYPOLICINGINCOMINGCLIENTTRAFCATTHEEDGENODESASACONSEQUENCE,TRAFCPOLICINGREQUIRESCONTINUOUSMONITORINGFORTRAFCPARAMETERCOMPLIANCEWITHTHESERVICELEVELAGREEMENTSLA,ASWELLASMONITORINGFORCONNECTIONPARAMETERVIOLATIONS,ANDUSEREQUIPMENTMALFUNCTIONING,AFUNCTIONKNOWNINATMASCONNECTIONMONITORINGTHEATMFORUMANDTHEITUTHAVEDENEDPARAMETERSTOMAINTAINTHEAGREEDTRAFCQOSITHASALSODENEDALGORITHMSFORPOLICINGTHETRAFCATTHEUSERNETWORKINTERFACEUNIFORBOTHCONSTANTBITRATECBRANDVARIABLEBITRATEVBRTHISALGORITHMISKNOWNASTHEGENERICCELL1788TRAFCMANAGEMENTANDCONTROLRATEALGORITHMGCRATHEGCRAISIMPLEMENTEDWITHTHECONTINUOUSSTATELEAKYBUCKETANDITISBASEDONTWOPARAMETERSTHEINCREMENTIANDTHELIMITLTHEIPARAMETERAFFECTSTHECELLRATETHELPARAMETERAFFECTSTHECELLBURSTFOREXAMPLE,THEPARAMETERSUTILIZEDINATMFORTRAFCMANAGEMENTAREPEAKCELLRATEPCRFORCBRANDVBRCONNECTIONS,SUSTAINABLECELLRATESCRFORVBRCONNECTIONS,ANDMAXIMUMBURSTSIZEMBSFORVBRCONNECTIONSTHESEPARAMETERSAREPROVIDEDBYTHEUSERDURINGTHECONNECTIONADMISSIONCONTROLCACATUNIINADDITION,THEBURSTTOLERANCEBTPARAMETERPUTSARESTRICTIONONTHEADDITIONALTRAFCABOVETHESCR,BEFOREITISTAGGEDEXCESSIVETRAFC85CONGESTIONMANAGEMENTFAILURESANDSEVERECOMPONENTDEGRADATIONSCANBESTATISTICALLYPREDICTABLEACCORDINGTOMANUFACTURERSFAILUREINTIMEFITDATAHOWEVER,THEREAREALSOUNPREDICTABLEFAILURES,SUCHASBERCUTSEITHERWAY,FAILURESANDDEGRADATIONSCAUSESTATISTICALUCTUATIONSOFTRAFCOWINTHENETWORKINANATTEMPTTOBYPASSTHEFAULTTHUS,THEREISANITEPROBABILITYTHATTRAFCTHROUGHANODEORLINKREACHESTHEMAXIMUMCAPACITYESTABLISHINGACONGESTIONCONDITIONMANIFESTEDBYNODEORLINKOVERLOAD,BANDWIDTHLOST,OREVENNETWORKCRASHINGENERAL,CONGESTIONMANAGEMENTISDENEDASANETWORKELEMENTSTATEUNABLETOMEETTHENEGOTIATEDNETWORKPERFORMANCEANDQUALITYOFSERVICEQOSOBJECTIVESASSUCH,CONGESTIONMANAGEMENTISSERIOUSLYADDRESSEDINDWDM,CONGESTIONMANAGEMENTISVERYIMPORTANTBECAUSESEVERELYDEGRADEDCOMPONENTSORFAULTYNODESANDLINKSAFFECTAHUMONGOUSAMOUNTOFTRAFCTHEREFORE,TRAFCREROUTINGNEEDSTOBEEXECUTEDEXPEDIENTLYANDEFCIENTLYTHUS,CONGESTIONMANAGEMENTNEEDSTOCONSIDERTHETYPEOFFAULTASEACHFAULTINUENCESBANDWIDTHOWATADIFFERENTLEVEL,TYPESOFSERVICESSUPPORTEDBYTHENETWORKASEACHTRAFCTYPEHASDIFFERENTREQUIREMENTS,NETWORKTOPOLOGYASEACHTOPOLOGYHASDIFFERENTSERVICESURVIVABILITYCHARACTERISTICS,SIZEOFNETWORK,INBOTHBANDWIDTHCAPACITYANDNUMBEROFNODES,ANDINTERNETWORKINGASTHEOVERALLPATHMAYCROSSSEVERALNETWORKPROVIDERDOMAINS,EACHCONSISTINGOFNODESWITHDIFFERENTSYSTEMCAPABILITIES86ROUTINGALGORITHMSINDWDMOPTICALNETWORKS,ALIGHTPATHCONNECTSASOURCEWITHADESTINATIONANDITMAYCONSISTOFTHESAMEWAVELENGTHFROMONEENDTOTHEOTHERENDORITMAYCONSISTOFSEVERALCONCATENATEDWAVELENGTHS,WHEREBYAWAVELENGTHCHANGESTOANOTHERBYMEANSOFWAVELENGTHCONVERTERSAMESHNETWORKWITHMANYNODESHASALARGENUMBEROFPOSSIBLESOURCETODESTINATIONPATHSADWDMMESHTOPOLOGYMAYBETHOUGHTASTHESUPERPOSITIONOFMANYMESHSINGLEWAVELENGTHTOPOLOGIESINDWDMOPTICALMESHNETWORKS,ONEPATHMAYOVERLAPWITHANOTHERPATHOVERONEORMORELINKSTHISMAKESTHEROUTINGALGORITHMMORECOMPLEXASTHESAMEWAVELENGTHFROMTWODIFFERENTSOURCESCANNOTCOEXISTOVERTHESAMEBERLINKIFTHISOCCURS,CROSSTALKSEVERELYDEGRADESTHETWOCHANNELSSOMESOLUTIONSUSEPOLARIZATIONSTATESTOMINIMIZECROSSTALKBUTTHELINKMUSTBEABLETOMAINTAINTHETWOPOLARIZATIONSTATESOVERITSFULLLENGTHTHUS,ATSETUPTIME,THEREISANITEPROBABILITYOFWAVELENGTHBLOCKING,PARTICULARLYWHENWAVELENGTHSAREDYNAMICALLYASSIGNEDINORDERTOMINIMIZETHEBLOCKINGPROBABILITYEFCIENTLY,OPTICALNODESREQUIRESPECICCONGURATION17987DISCOVERYOFOPTICALNETWORKTOPOLOGYFEATURES,WAVELENGTHCONVERSIONSTRATEGY,ANDSWITCHINGCAPABILITIESTHISISACCOMPLISHEDWITHTHEUSEOFROUTINGANDWAVELENGTHASSIGNMENTRWAALGORITHMSRWAALGORITHMSARECLASSIEDASSTATICANDDYNAMIC14DYNAMICRWAALGORITHMSASSIGNANDREMOVELIGHTPATHSRANDOMLYACCORDINGTONETWORKCONNECTIONREQUESTS,TRAFCUTILIZATION,ANDCONGESTIONSTATESTOINCREASENETWORKBANDWIDTHPERFORMANCE,ANODEADVERTISESITSSTATUSANDWAVELENGTHAVAILABILITYTOOTHERNODESBYMEANSOFPACKETSSUCHASADDRESSABLE,SHARED,CHANNELIZED,ANDHYBRIDTHISINCLUDESGLOBALNETWORKSTATEPARAMETERSONLINKSWITHINTHENETWORK,ASWELLASLOCALNODESTATUSTWODYNAMICROUTINGALGORITHMSARETHEALTERNATEPATHROUTINGANDUNCONSTRAINEDPATHROUTINGALTERNATEPATHROUTINGASSUMESTHATEVERYNODESTORESTHERSTNSHORTESTANDPREDETERMINEDPATHSTOEACHDESTINATIONBYUTILIZINGGLOBALANDLOCALNODELINKINFORMATIONCONGESTIONISDETERMINEDINPARTBYTHENUMBEROFWAVELENGTHSAVAILABLEPERPATHORLINKUNCONSTRAINEDROUTINGCONSIDERSALLPATHS,ANDITISBASEDONTHECOSTFUNCTIONOFALLLINKSWITHINTHENETWORKTODETERMINETHEOPTIMALENDTOENDPATHINGENERAL,DYNAMICROUTINGALGORITHMSPROCESSGLOBALNETWORKSTATEINFORMATIONTODETERMINETHEENDTOENDPATHALTERNATIVELY,THEDEECTIONORALTERNATEROUTINGALGORITHMISLIMITEDTOSTATEINFORMATIONFROMNEIGHBORINGNODESONLY,INWHICHCASELINKSARECHOSENONAHOPBYHOPBASISACCORDINGTOIT,ATEACHINTERMEDIATENODE,ACONTROLMESSAGEISPROCESSEDBEFOREBEINGFORWARDEDTOTHENEXTNODETHISCONTINUESONEHOPATATIMEUNTILTHEDESTINATIONNODECOMPLETESTHENALPROCESSOFTHECONTROLMESSAGEANDSENDSITBACKTOTHESOURCENODEDECISIONSONWAVELENGTHASSIGNMENTAREBASEDONTHESHORTESTPATHRST,FOLLOWEDBYALTERNATIVEROUTECONSIDERATIONSIFASPECICWAVELENGTHISUNAVAILABLETHELEASTCONGESTEDDEECTIONROUTINGSCHEMECHOOSESFROMALISTOFOUTGOINGLINKSBASEDONTHELARGESTNUMBEROFFEASIBLEWAVELENGTHSTHESHORTESTPATHRSTMETHODRESULTSINLOWERBLOCKINGWITHLESSTRAFCWHILEALEASTCONGESTEDPOLICYRESULTSINLOWERBLOCKINGATHEAVIERTRAFCLOADSTHOSEROUTINGSCHEMESAREAPPLICABLETOSINGLEBERMESHTOPOLOGY,ASWELLASMULTIBERNETWORKS87DISCOVERYOFOPTICALNETWORKTOPOLOGYWAVELENGTHASSIGNMENTALGORITHMSPROVIDETHEOPTIMALWAVELENGTHCONNECTIVITYTOACONNECTIONREQUESTWAVELENGTHASSIGNMENTISCLASSIEDASSTATICANDDYNAMICFORSTATICWAVELENGTHASSIGNMENT,ASEQUENTIALGRAPHCOLORINGAPPROACHISUSEDTONDTHEMINIMUMWAVELENGTHSCOLORSFOROVERAPATHFORTHEOPTICALNETWORKTOROUTEOPTICALCHANNELS,THEPHYSICALANDTHELOGICALLAYERTOPOLOGYOFTHENETWORKMUSTBEKNOWNTHATIS,EACHSWITCHINGNODEMUSTKNOWTHECHARACTERISTICSOFTHEADJACENTSWITCHINGNODESASWELLASTHEINTERCONNECTEDPORTSAMONGADJACENTSWITCHINGNODESTYPICALLY,THISISACCOMPLISHEDWITHSELFDISCOVERYPROTOCOLSSUCHPROTOCOLSUSESIGNALINGMESSAGESTHATLEARNANDSHARENODECONGURATIONANDTRAFCINFORMATIONUSINGSIGNALINGMESSAGES,APROTOCOLENABLESTHENODESTOESTABLISHANDMAINTAINANADJACENCYDATABASETHATREECTSTHESTATEOFTHENETWORKABOUTANODETHESEDATABASESAREREFRESHEDWHENEVERACHANGEINT
溫馨提示
- 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 人人文庫網(wǎng)僅提供信息存儲(chǔ)空間,僅對用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對任何下載內(nèi)容負(fù)責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對自己和他人造成任何形式的傷害或損失。
最新文檔
- 2025至2030中國惡心藥行業(yè)項(xiàng)目調(diào)研及市場前景預(yù)測評(píng)估報(bào)告
- 2025至2030運(yùn)動(dòng)和能量飲料行業(yè)發(fā)展趨勢分析與未來投資戰(zhàn)略咨詢研究報(bào)告
- 2025至2030中國數(shù)碼噴印產(chǎn)業(yè)前景預(yù)判與投融資趨勢預(yù)測報(bào)告
- 2025至2030中國自助火鍋行業(yè)發(fā)展分析及競爭策略與趨勢預(yù)測報(bào)告
- 2025至2030中國自動(dòng)寵物(貓和狗)廁所和和垃圾箱行業(yè)市場占有率及投資前景評(píng)估規(guī)劃報(bào)告
- 2025至2030中國臀部夾板行業(yè)發(fā)展趨勢分析與未來投資戰(zhàn)略咨詢研究報(bào)告
- 2025至2030中國腐植酸類生物刺激劑行業(yè)產(chǎn)業(yè)運(yùn)行態(tài)勢及投資規(guī)劃深度研究報(bào)告
- 2025至2030中國胰膽管塑料支架行業(yè)發(fā)展趨勢分析與未來投資戰(zhàn)略咨詢研究報(bào)告
- 電子競技項(xiàng)目負(fù)責(zé)人職責(zé)說明
- 2025至2030中國聚縮醛樹脂行業(yè)產(chǎn)業(yè)運(yùn)行態(tài)勢及投資規(guī)劃深度研究報(bào)告
- 2025年高考真題-英語(全國一卷) 含答案
- 頁巖氣儲(chǔ)層表征評(píng)價(jià)技術(shù)進(jìn)展及其未來發(fā)展趨勢分析
- 統(tǒng)編版高中政治必修三《政治與法治》期末復(fù)習(xí):選擇題刷題練習(xí)題(含答案解析)
- 2025-2030年中國線纜設(shè)備行業(yè)市場現(xiàn)狀供需分析及投資評(píng)估規(guī)劃分析研究報(bào)告
- 兒童情商課件
- 2025年湖北荊門市交通旅游投資集團(tuán)有限公司招聘筆試參考題庫含答案解析
- 食品產(chǎn)品溯源管理制度
- 2024年遼陽職業(yè)技術(shù)學(xué)院單招職業(yè)傾向性測試題庫附答案
- 護(hù)士思想政治教育
- 陜投集團(tuán)招聘真題2024
- 國家開放大學(xué)漢語言文學(xué)本科《古代詩歌散文專題》期末紙質(zhì)考試第三大題簡答題庫2025春期版
評(píng)論
0/150
提交評(píng)論