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1©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043ADVANCEDPERFORMANCEMEASUREMENTWITHCISCOIOSIPSLAWANGChunYang2©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043Prerequisites•Beforeattendingthissession,familiaritieswithCiscoIOS®IPServiceLevelAssurance(IPSLA)isessential•Configurationandgenericfeatureswillnotbecovered;thishasbeencoveredbyNMS-1204•Onlyneworadvancedtopics,aswellasdesignrecommendationswillbecovered3©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043Objectives•Understandtheinternals•Newfeaturesupdate•Performanceandscalabilityconsiderations•HowtogetthemostofIPSLA•FutureandIPSLAstrategicvision4©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043ThisIsNot...•AnintroductiontoIPSLA•RecommendationsonQoSconfiguration•Atalkonbackendnetworkmanagementapplications•Aspeculationonupcomingfeatures•…amarketingdocument5©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043Agenda•Reminder•IPSLAAccuracy•PerformanceandScalability•NewFeatures•DesignRecommendations•GettheMostoutofIPSLA•IPSLAInitiative6©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043TechnicalOverview•Widemeasurementcapabilities(UDP,TCP,ICMP,…)•Millisecondprecision(doesnotuseCiscoIOStimers)•AccessibleusingCLIandSNMP•Proactivenotification•Historicaldatastorage•Flexibleschedulingoptions•AlreadyinCiscoIOS(availableonmostplatforms)•Almostallinterfacessupported,physicalandlogical7©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043Reminder•IPSLAinanactiveprobingandmonitoringfeatureinCiscoIOS•Wideprotocolandapplicationscoverage:UDP,TCP,ICMP,HTTP,DNS,DHCP,FTP,…•ICMPorUDPoperationforconnectivity•Jitteroperationismostappropriatefornetworkmeasurements8©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitterOperation•Measuresthedelay,delayvariance(jitter)andpacketlossbygeneratingperiodicUDPtraffic•Measuresper-directionjitter,per-directionpacket-loss,androundtriptime•Detectandreportout-of-sequenceandcorruptedpackets•One-waydelayrequiresCiscoIOS12.2(2)Torlaterandclocksynchronizationbetweensourceanddestination•AlwaysrequiresIPSLAresponder9©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitter:MeasurementExampleIPSLARtx=ReceiveTstampforPacketXSendPacketsST2P2ST1P1P2i1RT2RT1ReceivePacketsP2P1i2RT1+d1RT2+d2ReplytoPacketsP2P1i3AT1AT2ReflectedPacketsP2P1i4ResponderDx=ProcessingTimeSpentBetweenPacketArrivalandTreatmentIPCoreStx=SentTstampforPacketXEachPacketContainsSTx,RTx,ATx,dxandtheSourceCanNowCalculate:JitterSD=(RT2-RT1)-(ST2-ST1)=i2-i1JitterDS=(AT2-AT1)-((RT2+d2)-(RT1+d1))=i4-i3Atx=ReceiveTstampforPacketX10©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitterOperationJitterComputation•Ifpacketsaresentwith10msinterval,positivejittermeanstheyhavebeenreceivedwithmorethan10msinterval•Negativejittermeanslessthan10msinterval•Zerojittermeanstheyarereceivedwiththesameinter-packetdelay(thevarianceiszero)•Jittershouldremainaslowaspossibleforreal-timetrafficsuchasvoiceoverIP;ageneralestimateisthatjittershallnotexceed30msend-to-end•Noneedtohaveclockssynchronized11©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043JitterCalculation:Beware!p1p2p3p1p2p3SendReceivet=0t=20t=40t=25i1=20msi1=20msi2=25msi2=15msi2-i1=+5msi2-i1=-5msPackettooLate:5msPacketOn-Time:0msIPSLAJitterRTPStreamJitterIfYouCountPositiveANDNegativeJitter,YouArePenalizedTwice;CountingOnlyPositiveJitterIsEnoughlat=50mslat=55mslat=50ms12©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitterOperation(Example)rtr1typejitterdest-ipaddr10.52.130.68\dest-port3456num-packets20rtrschedule1start-timenowUDPJitterProbeto10.52.130.68,Port3456Send20PacketsEachTimeSimpleExample:13©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitterOperation(Example)•SimulatingG.711VoIPcall•UseRTP/UDPports16384andabove,thepacketsizeis172bytes(160bytesofpayload+12bytesforRTP)•Packetsaresentevery20milliseconds•MarkedwithDSCPvalueof8(TOSequivalent0x20)rtr1typejitterdest-ipaddr10.52.130.68dest-port16384\num-packets1000interval20tos0x20frequency60request-data-size172rtrschedule1lifeforeverstart-timenowABCA=20msB=20s(1000x20ms)C=40s(60s–20s)14©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitterExample(NewCLI)ipsla1udp-jitter10.52.130.6816384num-packets1000\interval20request-data-size172tos20frequency60ipslaschedule1start-timenowrtr1typejitterdest-ipaddr10.52.130.68dest-port16384\num-packets1000interval20request-data-size172tos0x20frequency60rtrschedule1lifeforeverstart-timenowSameConfigurationwiththeNewandOldCLI:15©2005CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialNMS-3043UDPJitterOperation(Output)[1/3]etychon-vpn#shrtrop1CurrentOperationalStateEntryNumber:1ModificationTime:08:22:34.000PDTThuAug222002DiagnosticsText:LastTimethisEntrywasReset:NeverNumberofOctetsinusebythisEntry:1594NumberofOperationsAttempted:1CurrentSecondsLeftinLife:574OperationalStateofEntry:activeLatestOperationStartTime:08:22:34.000PDTThuAug222002La