CCIP-v2 2 pptQOS22S08L02

LinkEfficiencyMechanisms,ConfiguringClass-BasedHeaderCompression,HeaderCompressionOverview,TCPheadercompressionandclass-basedTCPheadercompression:CompressesIPandTCPheadersUsedtoreducetheoverheadofTCPsegmentsMosteffectiveonslowlinkswithmanyTCPsessionswithsmallpayloads(forexample,Telnet)RTPheadercompressionandclass-basedRTPheadercompression:CompressesIP,UDP,andRTPheadersUsedtoreducedelayandincreasethroughputforRTPImprovesvoicequalityMosteffectiveonslowlinksClass-basedheadercompressionCiscoIOSRelease12.2(13)T.Headercompressionisenabledonalink-by-linkbasis.,Class-BasedTCPHeaderCompression,MostInternetapplicationsuseTCPasthetransportprotocol.Mostoftheinformationintheheaders(IPandTCP)isstaticorpredictablethroughoutthesession.IP(20bytes)andTCP(20bytes)use40bytes.TCPheadercompressioncansqueezethesetwoheadersinto3to5bytes.Class-basedTCPheadercompressionallowscompressiononatrafficclass.Class-basedTCPheadercompressionisconfiguredviaMQC.,Class-BasedTCPHeaderCompressionExample,Linkbandwidthis64kbps.ThelinkisusedforanumberofinteractiveTCPsessions.PPPencapsulationisused.Averagepacketsizeis5bytes.Eachsegmenthas46bytesofoverhead(PPP,IP,andTCPheaders).,Class-BasedTCPHeaderCompressionExample(Cont.),Class-BasedRTPHeaderCompression,VoicesessionsuseRTP.RTPusesUDPfortransport.Mostoftheinformationintheheaders(IP,UDP,andRTP)isstaticthroughoutthesession.IP(20bytes),UDP(8bytes),andRTP(12bytes)use40bytes.RTPheadercompressioncansqueezethesethreeheadersinto2or4bytes.Class-basedRTPheadercompressionallowscompressiononatrafficclass.Class-basedRTPheadercompressionisconfiguredviaMQC.,Class-BasedRTPHeaderCompressionExample,Linkbandwidthis64kbps.ThelinkisusedforVoIP.PPPencapsulationisused.G.729codecisused(8kbpsofvoicedata,50samplespersecond,20bytespersample).Eachsegmenthas46bytesofoverhead(PPP,IP,UDP,andRTPheaders).,Class-BasedRTPHeaderCompressionExample(Cont.),ConfiguringClass-BasedHeaderCompression,compressionheaderiprtp|tcp,router(config-pmap-c)#,EnablesRTPorTCPIPheadercompressionforaspecifictrafficclass.Ifthertportcpoptionsarenotspecified,bothRTPandTCPheadercompressionsareconfigured.Thenumberofconcurrentcompressedconnectionsisautomaticallydeterminedbasedoninterfacebandwidth.CanbeusedatanylevelinthepolicymaphierarchyconfiguredwithMQC.,Example:ConfiguringClass-BasedTCPHeaderCompression,class-mapinteractivematchprotocoltelnet!policy-mapcust1classinteractivebandwidth64compressionheaderiptcp!ints0/0service-policyoutputcust1,Example:ConfiguringClass-BasedRTPHeaderCompression,class-mapvoipmatchprotocolrtp!policy-mapcust1!classvoippriority384compressionheaderiprtp!ints0/0service-policyoutputcust1,MonitoringClass-BasedHeaderCompression,routershowpolicy-mapinterfaceSerial0/0Serial0/0Service-policyoutput:cust1Class-map:voip(match-all)1005packets,64320bytes30secondofferedrate16000bps,droprate0bpsMatch:protocolrtpQueueingStrictPriorityOutputQueue:Conversation264Bandwidth384(kbps)Burst9600(Bytes)(pktsmatched/bytesmatched)1000/17983(totaldrops/bytesdrops)0/0compress:compress:headeriprtpUDP/RTPCompression:Sent:1000total,999compressed,41957bytessaved,17983bytessent3.33efficiencyimprovementfactor99%hitratio,fiveminutemissrate0misses/sec,0maxrate5000bps,showpolicy-mapinterfaceinterface-name,router,Displaysthepacketstatisticsofallclassesconfiguredforallservicepoliciesonthespecifiedinterface,Summary,TCPheadercompressioncompressestheIPandTCPheaders.RTPheadercompressioncompressestheIP,UDP,andRTPheaders.Headercompressionreducesdelay.Class-basedTCPheadercompressionenablesTCPheadercompressiononaper-classbasis.TCPheadercompressioncanreducetheheaderfrom40bytesto3to5bytes.RTPheadercompressionfeature(cRTP)canreducetheheaderfrom40bytestoa2-or4-byteheader(4byteswithUDPchecksumenabled),whichsignificantlyreducesdelayonslowlinks.,Summary(Cont.),Class-basedTCPandRTPhead