Zte ZXR10 8900 Series - Traffic Shaping; Queue Scheduling and Default 802.1 p

Chapter10QoSConguration
Itassumesthatpacketsarecolorlessincolor-blindmodebutas-
sumesthatpacketsaremarkedinacolorincolor-awaremode.
Acolorisassignedtoeachpacketpassingthroughtheswitchac-
cordingtoacertainprinciple(packetinformation)ontheswitch.
TheMakerrendersIPpacketsintheDSdomainaccordingtore-
sultsgivenbytheMeter .
Algorithmoftheabovetwomarkersaredescribedindetailsbelow.
SrTCMThisalgorithmisusedintheDiffservtrafcconditionertomea-
sureinformationowandmarkpacketsaccordingtothreetrafc
parameters(CommittedInformationRate(CIR),CommittedBurst
Size(CBS)andExcessBurstSizeEBS)).Theseparametersare
calledgreen,yellowandredmarkers.Apacketisgreenifitssize
islessthanCBS.ApacketisyellowifitssizeisbetweenCBSand
EBSandisredifitssizeexceedsEBS.
TrTCMThisalgorithmisusedintheDiffservtrafcconditionertomea-
sureIPinformationowandmarkapacketingreen,yellowor
redaccordingtothePeakInformationRate(PIR)andCommitted
InformationRate(CIR)andtheirrelevantburstsizes(CBSand
PBS).ApacketismarkedinredifitssizeexceedsPIR.Apacketis
markedinyellowifitssizeisbetweenPIRandCIRandismarked
ingreenifitssizeislessthanCIR.
TrafficShaping
Trafcshapingisusedtocontroltherateofoutputpacketsthus
sendingpacketsatevenspeed.Trafcshapingisusedtomatch
packetratewithdownlinkequipmenttoavoidcongestionand
packetdiscarding.
Trafcshapingistocachepacketswhoserateexceedsthelimited
valueandsendpacketsatevenrate;whiletrafcmonitoringisto
discardpacketswhoserateexceedsthelimitedvalue.Moreover ,
trafcshapingmakesdelaylongerbuttrafcmonitoringdoesnot
introduceanyextradelay.
Trafcshapingisclassiedintothefollowingtwokinds:
�Incomingportbandwidthtrafcshaping
�Outgoingportbandwidthtrafcshaping
QueueSchedulingandDefault
802.1p
EachphysicalportoftheZXR108900seriesswitchsupportseight
outputqueues(queue0toqueue7)calledCoSqueues.Switch
performsincomingportoutputqueueoperationaccordingtothe
CoSqueuecorrespondingto802.1pofpackets.Innetworkcon-
gestion,thequeueschedulingisgenerallyusedtosolvetheprob-
lemthatmultiplepacketscompetewitheachotherforresources
atthesametime.
CondentialandProprietaryInformationofZTECORPORATION93