CCIP-v2 2 pptISP 运营商系列QOS22S09L01

QoSBestPractices,UnderstandingTrafficClassificationBestPractices,QoSBestPracticesEnterpriseNetworks,Networksmustprovidepredictable,measurable,andsometimesguaranteedservices.AchievetherequiredQoSbymanagingthedelay,delayvariation(jitter),bandwidth,andpacket-lossparametersonanetwork.Classifyandmarktrafficasclosetothesourceaspossible.UseNBARtodiscovertheapplicationsonthenetwork.Ensurethatreal-timetrafficgetsprioritywithminimaldelay.Ensurethatbusiness-criticaltrafficiscorrectlyserviced.Ensurethatscavengertraffic(forexample,filesharing)doesnotconsumetoomuchvaluablebandwidth.UselinkefficiencytechniquesonWANlinks.,QoSBestPracticesServiceProviderNetworks,UseDiffServbackboneTypicallydefine3to4serviceclassesatthenetworkcore:Controlledlatency(EF)classOneortwocontrolledloadclassesBest-effortclassTypicallyoverprovisionthecontrolledlatencyclassbyafactorof2Mayhavemoreserviceclassesatthenetworkedge:Example:managementclassUseLLQorMDRR(GSR),WREDWhenpolicingandre-markingexcesstraffic,re-marktothesameAFclasswithhigherdropprobability:Example:Re-markAF31exceedingtraffictoAF32(donotre-markAF31toAF21),DesignApproachtoEnablingQoS,QoSTrafficRequirements:Voice,Latency150ms*Jitter30ms*Loss1%*Requiresguaranteedprioritybandwidthpercall150bps(+Layer2overhead)guaranteedbandwidthforvoice-controltrafficpercall*one-wayrequirements,ProvisioningforVoice:VoIPBandwidthReferenceTables,QoSTrafficRequirements:Videoconferencing,Latency150ms*Jitter30ms*Loss1%*Minimumprioritybandwidthguaranteerequiredis:Videostream+20%Forexample,a384-kbpsstreamwouldrequire460kbpsofbandwidth*One-wayrequirements,QoSTrafficRequirements:Data,Differentapplicationshavedifferenttrafficcharacteristics.Differentversionsofthesameapplicationcanhavedifferenttrafficcharacteristics.,ProvisioningforData:GeneralPrinciples,Profileapplicationstotheirbasicnetworkrequirements.Donotoverengineerprovisioning.Usenomorethanfourtofivetrafficclassesfordatatraffic:Mission-Critical:LocallydefinedcriticalapplicationsTransactional:ERP,SAP,OracleBest-Effort:E-mail,unspecifiedLess-than-Best-Effort(Scavenger):Peer-to-peerapplicationsDonotassignmorethanthreeapplicationstomission-criticalortransactionalclasses.Onlygroupapplicationswithcommoncharacteristicstogetherintothesameclass.Mostapplicationsfallunderbesteffort;makesurethatadequatebandwidthisprovisionedforthisdefaultclass.SeekexecutiveendorsementofrelativerankingofapplicationprioritypriortorollingoutQoSpoliciesfordata.,QoSRequirementsSummary,TrafficClassificationandScheduling,IdentifythenetworktrafficanditsQoSrequirements.Classifythenetworktrafficintotheappropriatetrafficclassesandmarkthenetworktrafficasclosetothesourceaspossible.Definetheschedulingpolicyforeachtrafficclass.,EnterpriseWANEdgeBandwidthAllocationExample,TheamountofmaximumbandwidthtobeallocatedfortheLLQclassdependsonmanyfactorssuchastherouterplatform,thetrafficprofiles,andQoSfeaturesenabled.,QoSBaselineClassificationSummary,QoSBaselineClassificationSummary(Cont.),WANEdgeLLQConfiguration,class-mapmatch-allROUTINGmatchipdscpcs6class-mapmatch-allVOICEmatchipdscpefclass-mapmatch-allVIDEO-CONFmatchipdscpaf41class-mapmatch-allSTREAM-VIDEOmatchipdscpcs4class-mapmatch-allMISSION-CRITmatchipdscp25class-mapmatch-anyVOICE-CONTROLmatchipdscpcs3matchipdscpaf31class-mapmatch-allTRANSACTmatchipdscpaf21class-mapmatch-allNETWORK-MGMTmatchipdscpcs2class-mapmatch-allBULKmatchipdscpaf11class-mapmatch-allSCAVENGERmatchipdscpcs1,policy-mapWAN-EDGEclassROUTINGbandwidthpercent3classVOICEprioritypercent18classVIDEO-CONFprioritypercent15classSTREAM-VIDEObandwidthpercent10classMISSION-CRITbandwidthpercent12random-detectdscp-basedclassVOICE-CONTROLbandwidthpercent2classTRANSACTbandwidthpercent8random-detectdscp-basedclassNETWORK-MGMTbandwidthpercent2classBULKbandwidthpercent4random-detectdscp-basedclassSCAVENGERbandwidthpercent1classclass-defaultbandwidthpercent25random-detectdscp-based,Ifthedefaultclassisallocatedabandwidth,WFQcannotbeenabledforthetrafficwithinthedefaultclass.ThisistrueforallplatformsexcepttheCisco7500(andsoontheCisco7200).,EnterprisetoServiceProviderQoSClassMappingExample,WANEdgeLLQConfigurationExample2,Mappingenterpriseserviceclassestoserviceprovidersupportedserviceclasses,Summary,QoSBestPracticesisachievedby:Managingdelay,delayvariation(jitter),bandwidth,andpacketlossClassifyingandmarkingtrafficasclosetothesourceaspossibleUsingNBAREnsuringthatreal-timetrafficgetsprioritywithminimaldelayEnsuringthatbusiness-criticaltrafficiscorrectlyservicedEnsuringthatscavengertrafficconsumesonlyasmallamountofbandwidthUsinglinkefficiencytechniquesQoShasspecificrequirementsforenterprisetrafficclasses:voice,videoconferencing,bulkdata,andmission-criticaldata.,Eachenterprisetrafficclasshasdelay,jitter,packetloss,andbandwidthrequiremen