Zte ZXR10 5900E Series User manual

ZXR105900ESeries
Easy-MaintenanceMPLSRoutingSwitch
CongurationGuide(QoS)
Version:3.00.11
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RevisionHistory
RevisionNo.RevisionDateRevisionReason
R1.02015–01–15Firstedition
SerialNumber:SJ-20150114102049-008
PublishingDate:2015-01-15(R1.0)
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Contents
AboutThisManual.........................................................................................I
Chapter1PortQoSConguration............................................................1-1
1.1PortQoSOverview.............................................................................................1-1
1.2ConguringPortQoS.........................................................................................1-4
1.3MaintainingthePortQoS..................................................................................1-10
1.4PortQoSCongurationExample.......................................................................1-14
Chapter2FlowQoSConguration...........................................................2-1
2.1Trafc-basedQoSOverview...............................................................................2-1
2.2ConguringFlowQoS.........................................................................................2-5
2.3FlowQoSMaintenance.....................................................................................2-11
2.4FlowQoSCongurationExample......................................................................2-12
2.4.1TrafcLimitandStatisticsCongurationExample.....................................2-12
2.4.2PolicyRoutingCongurationExample.....................................................2-16
2.4.3HierarchyMeterCongurationExample...................................................2-21
2.4.4TrafcMirroringCongurationExample...................................................2-23
2.4.5ConguringtheTrafcLimitBasedonthevlan.........................................2-25
Figures.............................................................................................................I
Glossary........................................................................................................III
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AboutThisManual
Purpose
ThismanualistheZXR105900ESeries(V3.00.11)Easy-MaintenanceMPLSRouting
SwitchCongurationGuide(QoS),whichisapplicabletotheZXR105900E(V3.00.11)
seriesswitches.
IntendedAudience
Thismanualisintendedfor:
lNetworkplanningengineer
lDebuggingengineer
lAttendant
WhatIsinThisManual
Thismanualcontainsthefollowingchapters:
Chapter1,PortQoS
Conguration
ProvidestheoverviewandprinciplesofPortQoSconguration,related
congurationandmaintenancecommands,andcongurationexamples.
Chapter2,FlowQoS
Conguration
ProvidestheoverviewandprinciplesofFlowQoSconguration,related
congurationandmaintenancecommands,andcongurationexamples.
Conventions
Thismanualusesthefollowingtypographicalconventions:
ItalicsVariablesincommands.Itmayalsorefertootherrelatedmanualsanddocuments.
BoldMenus,menuoptions,functionnames,inputelds,optionbuttonnames,checkboxes,
drop-downlists,dialogboxnames,windownames,parameters,andcommands.
Constant
width
Textthatyoutype,programcodes,lenames,directorynames,andfunctionnames.
[]Optionalparameters.
{}Mandatoryparameters.
|Separatesindividualparameterinseriesofparameters.
Note:providesadditionalinformationaboutacertaintopic.
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Chapter1
PortQoSConguration
TableofContents
PortQoSOverview.....................................................................................................1-1
ConguringPortQoS.................................................................................................1-4
MaintainingthePortQoS.........................................................................................1-10
PortQoSCongurationExample..............................................................................1-14
1.1PortQoSOverview
IntroductiontoPortQoS
InatraditionalInternetProtocol(IP)network,allpacketsareprocessedwithoutany
difference.RoutersusetheFirstInFirstOut(FIFO)policytoprocesspacketsandthe
best-effortprincipletotransmitpacketstodestinations.However,therouterscannot
guaranteetheperformancesuchaspackettransmissionreliability,delay,andsoon.
WiththedevelopmentofnewapplicationsinanIPnetwork,usershavemorerequirements
forservicequality.Thebest-effortinatraditionalIPnetworkcannotmeettherequirements
ofapplications.Forexample,intheVoIPservice,ifthetransmissiondelayofpacketsis
toolong,userscannotbearit.Afeasiblemethodtosolvetheproblemistoprovidethe
QualityofService(QoS)abilityfortheInternet.
QoSisusedtoprovidedifferentservicequalities(suchasprovidingaspecialbandwidth,
reducingthepacketlossrate,delay,anddelayjitter)inaccordancewithdifferent
requirementsofapplications.
PortQoSPrinciple
TheportQoSisanimportantpartoftheQoSfunction.ItisaQoSsub-modulecongured
onthebasisofports.Themainfunctionsareasfollows:
lTrafclimit
Thetrafclimitfunctionbasedonportsistolimitthetrafcrateofthisport.Forthe
trafcexceedingthecommittedrate,performthefollowingoperations:
àDroporforwardpackets(Redpacketsaredropped,andyellowpacketsare
allowedbydefault.)
àModifytheDSCPvalueofapacket.
àModifythedroppriority.Apacketwithahigherdropprioritywillbedroppedrst.
Thedefaultpriorityis3foraredpacket,2forayellowpacket,and1foragreen
packet.
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ZXR105900ESeriesCongurationGuide(QoS)
àThetrafclimitbasedontheportdoesnotcauseanyextradelay.
ThetrafclimitbasedontheportusestheMMUregister.Ifitisnotsupportedbythe
ACLrule,extrapacketstothisportwillbedroppedinthedefaultdropmode.Thatis
tosay,thecurrentpacketswillbedroppedifnotokenbucketisobtained.
Aftertherateislimited,thepacketwillbecoloredinsrTCMBLINDmode.TheEBS
isequaltotheCBS,sothereareonlyredandgreenpackets,andnoyellowpackets.
Ifatokenisobtainedfromthetokenbucket,thepacketwillbegreen.Ifnotokenis
obtainedfromthetokenbucket,thepacketwillbered.Theredpacketsaredropped
bydefault,andthegreenpacketsareallowed.
lTrafcshaping
Thetrafcshapingfunctionlimitstherateofpacketssentfromtheport.Inthiscase,
packetscanbesentoutatanaveragespeed.Thetrafcshapingfunctionismainly
usedtomatchtherateofpacketswiththerateofdownstreamdevicestoavoidpacket
congestionandpacketloss.
Thedifferencebetweentrafcshapingandtrafclimitisasfollows:Thetrafcshaping
functionbuffersapacketthatexceedsthecommittedrate,andthensendsthepacket
atanaveragespeed.However,thetrafclimitfunctiondiscardsthepacketbecause
thepacketexceedsthecommittedrate.Thetrafcshapingfunctioncausesthedelay,
butthetrafclimitfunctiondoesnotcauseanydelay.
ThetrafcshapingfunctionisalsoimplementedthroughtheMMUregister.
lQueuescheduling
EachphysicalportoftheZXR105900Esupportseightoutputqueues(queue0-7)
whicharecalledCoSqueues.Theswitchperformstheoutputoperationonthe
ingressinaccordancewiththeCosqueuecorrespondingto802.1pofpackets.
Whennetworkcongestionoccurs,multiplepacketsmayoccupytheresources.This
problemissolvedthroughthequeueschedulingfunction.
TheZXR105900Esupportsthreetypesofqueuescheduling,includingStrictPriority
(SP),WeightedRoundRobin(WRR),andDecitWeightedRoundRobin(DWRR).
Eightoutputqueuesofthisportusedifferentschedulingmodes.
àStrictPriority(SP)
Inthismode,thepacketineachqueueisstrictlyscheduledinaccordancewiththe
priority.Thepacketsinthequeuewiththehighestprioritywillbescheduledrst.
Whenthepacketswiththehighestpriorityinthequeuearescheduledcompletely,
thepacketsinthequeuewithasecondhighestprioritywillbescheduledthen,
andsoon.
Thestrictpriorityschedulingensuresthatpacketsofkeyservicesareprocessed
rst.Inaddition,theQoSofkeyservicesareguaranteed.However,thequeue
withalowerprioritymayneverbeprocessed.
àWeightedRoundRobin(WRR)
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Chapter1PortQoSConguration
Thismodeensuresthateachqueuehasachancetobescheduled.Theweight
ofeachqueueisdifferent,sothetimeofeachqueuetobescheduledisdifferent.
Theweightreferstotheproportionofresourcesobtainedbyeachqueue.The
packetsinaqueuewithahigherprioritytakeprecedenceoverthatinaqueue
withalowerpriority.
àDecitWeightedRoundRobin(DWRR)
Thismodealsoensuresthateachqueuehasachancetobescheduled.The
weightofeachqueueisalsodifferentfromanotherqueue.Thedifference
betweenDWRRandWRRis:TheweightconguredinDWRRindicatesthe
scheduledbytesofeightqueuesduringeachscheduling(unit:kbyte),andthe
weightconguredinWRRindicatesthenumberofscheduledpacketsofeach
queueduringeachscheduling.So,thesizeofDWRRpacketshaslessinuence
onthebandwidth.
lDefaultpriority
Whenpacketcongestionoccurs,theswitchwilldiscardpacketsselectively.In
general,thisselectiverulereferstothedroppriority.Eachpackettotheportfromthe
egresswillbecoloredinaccordancewithitscarried802.1plabel(packetpriority).
Packetswithdifferentprioritieswillbecoloredgreen(low),yellow(middle),orred
(high)inaccordancewithacertainmappingrelationship.Packetsaredroppedin
accordancewiththecolorwhenqueuecongestionoccurs.Thecolorcanalsobe
usedbyotherdroppolicies.
Themappingtablebetweenthe802.1Puserpriorityandthelocaldroppriorityofa
switchmustbeset.
Whenaswitchreceivesapacket,itdeterminestheCoSvalueofthepacket.Fora
TAGpacket,theCoSvaluereferstothe802.1Puserpriorityinthepacket.Fora
non-TAGpacket,theswitchdeterminesthelocalpriorityofapacketinaccordance
withthedefaultlocalpriorityofthereceivingport,andthendeterminestheCoSvalue
ofthepacketinaccordancewiththerelationshipbetweenthelocalpriorityandthe
CoSvalue.Afterthat,themappingtabledeterminesthedroppriorityofthepacketin
accordancewiththeCoSvalue.Thedefaultvalueis0.
Thedroppriorityisconguredontheingressinterface.
lLocalpriority
Thelocalpriorityhereisdifferentfromthecommon"internalpriority"usedintheACL
rule.Thelocalpriorityhereisamappingrelationshipbetweenthe802.1ppacketand
eightCoSqueuesoftheegress.Thatistosay,802.1ppacketswithdifferentpriorities
(level0-7)willbesenttodifferentCoSqueuesforscheduling.
Thelocalprioritymappingisconguredontheingress.
Thelocalmappingrelationshipisvalidonlyforthelocalswitchingchip.Itbecomes
invalidwhentheingressusedforthemappingcongurationandtheegressusedfor
theschedulingarenotinthesameboardorthesameswitchingchip.
lTailDrop
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ZXR105900ESeriesCongurationGuide(QoS)
Thetaildroppolicyisusedfortheegressofaqueue.Thepacketisdroppedin
accordancewithitscolor.Threeparametersneedtobeset,includingCIR,CBS,and
EBS.
àWhenthequeuelengthexceedsthetotalthreshold,allpacketswillbedropped.
àWhenthequeuelengthexceedsthedropthresholdforyellowpackets,yellow
packetswillbedroppedatasetrate.
àWhenthequeuelengthexceedsthedropthresholdforredpackets,allred
packetswillbedropped.
lDSCPMapping
Whenapacketentersaninterface,thenewDSCPvalue,thepacketpriority,andthe
droppriorityofthepacketcanbesetinaccordancewiththeDSCPindex.Whenthe
DSCPmappingfunctionofthisportisenabled,theDSCPvalueisnotchanged,the
packetpriorityissettoDSCP/8,andthedroppriorityissetto0bydefault.
lBandwidthRestriction
Thebufferresourcesofaqueuearelimited,somultiplepacketsmayoccupythe
resourceswhennetworkcongestionoccurs.Whentheminimumbandwidthandthe
maximumbandwidtharecongured,thebandwidthobtainedbyeachqueueisnot
lessthantheminimumbandwidthandnotmorethanthemaximumbandwidthwhen
multiplepacketsseizeresources.Thisensuresthateachqueuehasachanceto
obtainthebandwidth.
lWeightedRandomEarlyDetection
TraditionaltaildropschemesmaycausealotofTCPmessagesbeingdroppedand
leadtoglobalTCPsynchronization.ButWeightedRandomEarlyDetection,amethod
generallyusedtoavoidcongestion,combinestheIPpriorityandrandomearly
detectionpolicyandprovidesdifferentservicesfordifferenttypesofservices.Groups
havinghigherprioritiesareprocessedrstandpacketsaredroppedrandomly.This
avoidsmultipleTCPlinksfromreducingthetransmissionspeedatthesametime.
1.2ConguringPortQoS
ConguringTrafcLimit
Tosetatrafclimit,performthefollowingstep:
CommandFunction
ZXR10(config-pm-qos)#traffic-limit<interface>rate-limit
<1-40000000>bucket-size<1-4096>
Setsthetrafclimit.
ConguringTrafcShaping
Tosettrafcshaping,performthefollowingsteps:
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