Enterasys Matrix 7G4270-09 User manual
February 22, 2008 Page 1 of 29
QoS Configuration
ThischapterdescribestheQoSfeatureasitisimplementedontheMatrixN‐SeriesSwitch/Router,
SecureStack,andSecureSwitch.
What Is Quality of Service?
QualityofService(QoS)is:
•Amechanismforthemanagementofbandwidth
•Theabilitytogivepreferentialtreatmenttosomepacketsoverothers
•Baseduponpacketclassificationandforwardingtreatment
Youconfigurepacketpreferenceandforwardingtreatmentbaseduponaflow’ssensitivityto
delay,delayvariation(jitter),bandwidth,availabilityandpacketdrop.QoSusespacketpriority,in
conjunctionwithqueuetreatmentconfiguration,todeterminetheinterface’sinboundand
forwardingbehaviorforthispacket.Packetpreferenceandforwardingtreatmentforagivenflow
canbeappliedtorolesconfiguredinEnterasyspolicy.
Why Would I Use It in My Network?
WithoutQoS,allpacketsaretreatedasthoughthedeliveryrequirementsandcharacteristicsof
anygivenpacketareequaltoanyotherpacket.Inotherwords,non‐QoSpacketdeliveryisnot
abletotakeintoaccountapplicationsensitivitytopacketdelay,jitter,amountofbandwidth
Note: Please see the Enterasys Matrix™ X Secure Core Router Configuration Guide for a
complete discussion of QoS as it applies to the Matrix X-Series.
For information about... Refer to page...
What Is Quality of Service? 1
Why Would I Use It in My Network? 1
How Can I Implement Quality of Service? 2
Quality of Service Overview 2
Understanding QoS Configuration on the Matrix N-Series 9
Feature Differences 20
The QoS CLI Command Flow 21
QoS Configuration Example 23
Terms and Definitions 28
How Can I Implement Quality of Service?
February 22, 2008 Page 2 of 29
required,packetloss,oravailabilityrequirementsoftheflow.QoSprovidesmanagement
mechanismsfortheseflowcharacteristics.
QoSachievesitsbandwidthmanagementcapabilitiesby:
•Settingprioritiesthatdefinetraffichandling
• Dedicatingbandwidthandprioritizingqueuingforspecificapplications,andreducingpacket
transmissiondelayandjitter
• Managingcongestionbyshiftingpacketlosstoapplicationsthatcantolerateit
How Can I Implement Quality of Service?
QoSdetermineshowaflowwillbetreatedasittransitsthelink.Todeterminehowaflowshould
betreated,youmustfirstunderstandthecharacteristicsoftheflowsonyournetwork,and
secondly,youmustidentifytheseflowsinawaythatQoScanrecognize.Inthissense,QoSisthe
thirdstepinathreestepprocess.Thethree‐stepsEnterasysrecommendsforconfiguringQoSare:
• UnderstandyournetworkflowsusingNetFlow
• AssociatetheflowsonyournetworkwithawelldefinedroleusingEnterasyspolicy
• ConfiguretheappropriatelinkbehaviorforthatrolebyassociatingtherolewithaQoS
configuration
Quality of Service Overview
QoSisallaboutmanagingthebandwidthinamannerthatalignsthedeliverycharacteristicsofa
givenflowwiththeavailableportresources.InaQoScontext,aflowisastreamofIPpacketsthat
areclassifiedwiththesameclassofserviceasittransitstheinterface.QoSmanagesbandwidthfor
eachflowbytakingadvantageofitsabilityto:
• Assigndifferentprioritylevelstodifferentpacketflows
•Markorre‐markthepacketpriorityatportingresswithaTypeofService
•Sortflowsbytransitqueuesuchthatahigherpriorityqueuegetspreferentialaccessto
bandwidthduringpacketforwarding
•Limittheamountofbandwidthavailabletoagivenflowbyeitherdropping(ratelimit)or
buffering(rateshape)packetsinexcessofconfiguredlimits
TheseQoSabilitiescollectivelymakeupaClassofService(CoS).Theremainderofthissection
willbrieflydescribeCoSanditscomponents.
Class of Service (CoS)
YouimplementQoSfeaturesinaClassofService(CoS).Howthefirmwaretreatsapacketasit
transitsthelinkdependsuponthepriorityandforwardingtreatmentsconfiguredintheCoS.Up
to256uniqueCoSentriescanbeconfigured.CoSentries0–7areconfiguredbydefaultwithan
802.1ppriorityassignedanddefaultforwardingtreatment.Forpurposesofbackward
compatibility,CoSentries0–7cannotberemoved.CoSentries8‐255canbeconfiguredforthe
followingservices:
• 802.1ppriority
•IPToSrewritevalue
Quality of Service Overview
February 22, 2008 Page 3 of 29
•PriorityTransmitQueue(TxQ)withconfigurableforwardingbehavior
•In‐boundand/oroutboundrateLimiter(IRL)pertransmitqueue
• Outboundrateshaperpertransmitqueue
TheCoSconfigurationforeachservicecanbeeasilyviewedusingtheCoSsettingtables.Portsare
bundledintoportgroupswiththegroupassignedtoaCoS,significantlycuttingdownon
operationaloverheadandcomplexity.
CoS Priority and ToS Rewrite
ThetwoparametersconfigurableforCoSpriorityare802.1pandTypeofService(ToS).EachCoS
canbemappedtoan802.1ppriorityandaToSrewritevalue.The802.1pparameteris:
•AsubsetofToSwithvalues0–7(upper3bitsofthe8bitToSfield)
• Supportedinbothlayer2andlayer3
TheToSparameteris:
•An8‐bitfieldwithvalues0–255
• Supportedinlayer3only
•AlsoreferredtoastheDifferentiatedServicesCodePoint(DSCP)whenlimitedtothelower5
bitsofthefield
Figure 1displaystherelationshipbetweenyourapplication,prioritylevel,802.1p,andToS
assignments(shownhereusingDSCPterminology).
QoSpriority/ToSconfiguration:
• Derivesitscharacteristicrequirementsfromtheend‐systemapplication.
•Isconfiguredontheedgedevicetheapplicationisconnectedto
•Ispropagatedthroughthenetworkintheprotocolpacketheader
Quality of Service Overview
February 22, 2008 Page 4 of 29
Figure 1 Assigning and Marking Traffic with a Priority
TheICMPprotocol,usedforerrormessaging,hasalowbandwidthrequirement,withahigh
tolerancefordelayandjitter,andisappropriateforalowprioritysetting.HTTPandFTP
protocols,usedrespectivelyforbrowser‐generatedandfiletransfertraffic,haveamediumtohigh
bandwidthrequirement,withamediumtohightolerancefordelayandjitter,andareappropriate
foramediumprioritylevel.Voice(VoIP),usedforvoicecalls,hasalowbandwidthrequirement,
butisverysensitivetodelayandjitterandisappropriateforahighprioritylevel.
SeeRFC1349forfurtherdetailsonToS.SeeRFCs2474and2475forfurtherdetailsonDSCP.
Preferential Queue Treatment for Packet Forwarding
Therearethreetypesofpreferentialqueuetreatmentsforpacketforwarding:strict,weightedfair,
andhybrid.
Strict Queuing
WithStrictPriorityQueuing,ahigherpriorityqueuemustbeemptybeforealowerpriorityqueue
cantransmitanypackets.StrictqueuingisdepictedinFigure 2.Inboundpacketsenteronthe
upperleftandproceedtotheappropriatequeue,basedupontheTxQconfigurationintheCoS.
Outboundpacketsexitthequeuesonthelowerright.Atthistimeonlyqueue3packetsare
forwarded.Thiswillbetrueuntilqueue3iscompletelyempty.Queue2packetswillthenbe
forwarded.Queue1packetswillonlyforwardifbothqueue2andqueue3areempty.Queue0
packetswillonlyforwardifallotherqueuesareempty.Strictqueuingassuresthatthehighest
priorityqueuewithanypacketsinitwillget100percentofthebandwidthavailable.Thisis
particularlyusefulforoneormoreprioritylevelswithlowbandwidthandlowtolerancefordelay.
Theproblemwithstrictqueuingisthatshouldthehigherlevelqueuesneverfullyempty,lower
levelqueuescanbestarvedofbandwidth.
Quality of Service Overview
February 22, 2008 Page 5 of 29
Figure 2 Strict Priority Queuing Packet Behavior
Weighted Fair Queuing
Withweightedfairqueuing,queueaccesstobandwidthisdividedupbypercentagesofthetime
slicesavailable.Forexample,if100percentisdividedinto64timeslices,andeachqueueis
configuredfor25percent,eachqueuewillget16timeslices,afterwhichthenextlowestpriority
queuewillgetthenext16,andsoon.Shouldaqueueemptybeforeusingitscurrentshareoftime
slices,thenextpriorityqueueinheritsthetimeslicesthatremain.Figure 3depictshowweighted
fairqueuingworks.Inboundpacketsenterontheupperleftoftheboxandproceedtothe
appropriatepriorityqueue.Outboundpacketsexitthequeuesonthelowerright.Queue3has
accesstoitspercentageoftimeslicessolongastherearepacketsinthequeue.Thenqueue2has
accesstoitspercentageoftimeslices,andsoonroundrobin.Weightedfairqueueingassuresthat
eachqueuewillgetatleasttheconfiguredpercentageofbandwidthtimeslices.Thevalueof
weightedfairqueueingisinitsassurancethatnoqueueisstarvedforbandwidth.Thedownside
ofweightedfairqueueingisthatpacketsinahighpriorityqueue,withlowtolerancefordelay,
willwaituntilallotherqueueshaveusedthetimeslicesavailabletothembeforeforwarding.So
weightedfairqueuingwouldnotbeappropriateforapplicationswithhighsensitivitytodelayor
jitter,suchasVoIP.
Quality of Service Overview
February 22, 2008 Page 6 of 29
Figure 3 Weighted Fair Queuing Packet Behavior
Hybrid Queuing
Hybridqueuingcombinesthepropertiesofbothstrictandweightedfairqueuing.Figure 4on
page 7,depictshybridqueuing.Theconfigurationisforstrictqueuingonqueue3andweighted
fairqueuingfortheremainingqueues,withqueue2receiving50percentoftheremainingtime
slices,andtheotherqueuesreceiving25percenteach.Thebenefitofhybridqueueingisthat
queuesconfiguredasstrictwillreceiveallthebandwidththatisavailableintheorderoftheir
priorityuntilempty.Remainingbandwidthwillbeusedbytheweightedfairqueuesbasedupon
thetimeslicepercentagesconfigured.Thedownsideremainsthatanytimestrictqueuingisused,
shouldthestrictqueuesneverfullyempty,remainingqueueswillbestarvedofbandwidth.
Quality of Service Overview
February 22, 2008 Page 7 of 29
Figure 4 Hybrid Queuing Packet Behavior
Rate Limiting
Ratelimitingisusedtocontroltherateoftrafficentering(inbound)and/orleaving(outbound)a
switchperCoS.Ratelimitingallowsforthethrottlingoftrafficflowsthatconsumeavailable
bandwidth,intheprocessprovidingroomforotherflows.Ratelimitingguaranteesthe
availabilityofbandwidthforothertrafficbypreventingtheratelimitedtrafficfromconsuming
morethantheassignedamountofanetwork’sresources.Ratelimitingaccomplishesthisby
settingacaponthebandwidthutilizationofspecifictypesofbothinboundandoutboundtraffic.
Whenaratelimithasbeenexceeded,theCoScanbeconfiguredtoperformoneorallofthe
following:recordaSyslogmessage,sendanSNMPtraptoinformtheadministrator,and
automaticallydisabletheport.
Figure 5illustrateshowburstytrafficisclippedabovetheassignedthresholdwithratelimiting
applied.
Quality of Service Overview
February 22, 2008 Page 8 of 29
Figure 5 Rate Limiting Clipping Behavior
Rate Shaping
RateShapingthrottlestherateatwhichaporttransmits(outbound)queuedpackets.RateShaping
bufferspacketsreceivedabovetheconfiguredrateonaperCoSbasis,ratherthandroppingthem.
Onlywhenbuffercapacityisexceededarepacketsdropped.Rateshapingmaybeconfiguredfora
CoSonaport,foran802.1ppriorityonaport,orforallClassesofServiceonaport.
Figure 6illustrateshowburstytrafficissmoothedoutwhenitburstsabovetheassignedthreshold
withrateshapingapplied.
Figure 6 Rate Shaping Smoothing Behavior
Rateshapingretainsexcesspacketsinaqueueandthenschedulesthesepacketsforlater
transmissionovertime.Therefore,thepacketoutputrateissmoothedandburstsintransmission
arenotpropagatedasseenwithratelimiting.
Rateshapingcanbeimplementedformultiplereasons,suchascontrollingbandwidth,tooffer
differinglevelsofservice,ortoavoidtrafficcongestiononotherlinksinthenetworkbyremoving
theburstinesspropertyoftrafficthatcanleadtodiscardedpackets.Rateshapingisimportantfor
real‐timetraffic,wherepacketlossisextremelydetrimentaltotheseapplications.Insteadof
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 9 of 29
discardingtrafficimposedbyratelimiting,delaysareinducedintoitstransmissionbyretaining
thedataforfuturetransmission.However,thedelaysmustalsobeboundedtothedegreethatthe
trafficissensitivetodelays.
Understanding QoS Configuration on the Matrix N-Series
ThissectiondiscussesthesixcomponentsforconfiguringQoSanddisplayingQoSstatusonan
N‐Seriesswitchrouter:
CoSPort‐Type:Determinesthetransmitqueue(TxQ)andInboundRateLimiting(IRL)resource
capabilitiesoftheportsinyoursystem.Knowledgeofthesecapabilitiesisimportantwhen
configuringqueuebehaviors.Portgroupmembershipandtheportresourcesavailableare
determinedbyporttype.
CoSPortGroups:Provideforthegroupingofportsbythesameclassofservicefeaturesandport
type.
CoSPortResourceTable:Enablestheassociationofratelimiterandrateshapervaluestoaport.
CoSReferenceMappingTable:MapsyourdefinedTxQandIRLindexreferences,usedbythe
CoSsettingstable,tothephysicalqueueandratelimitersettingscreatedintheport‐resource
table.
CoSSettingsTable:UsedforCoSparameterassignmentandcontainsthecurrentsettingsforeach
classofservicefeature.Eachclassofserviceentryconsistsofanentryindex,an802.1ppriority,an
optionalToSvalue,atransmitqueuereference,andanoptionalIRLreference.
CoSState:AglobalsettingthatmustbeenabledforaconfiguredCoStoaffectportbehavior.
Whenenabled,CoSstateassociatedwithaportsupersedescurrentdefaultormodifiedport‐level
controlsforpriorityqueuemapping,portratelimiting,andtransmitqueue.Whendisabledthe
portsettingsapply.
NumerousQoSvaluesareassociatedwitheachotherthroughreference.Withtheexceptionof
802.1ppriorityandToS,CoSvaluesarefirstmappedtoaportgroup,whichassociatesaCoS
configurationwithaporttype.AportgrouphasthefollowingCoSparametersassociatedwithit:
•Physicalport(s)
•Strictorweightedfairqueuingbehavior
• Rate‐limitsetting(s)
• Rate‐shapingsetting(s)
•Aportqueue
•Aportreference
UnderstandinghowtheseparametersarefirstmappedtotheportgroupandthentoaTxQorIRL
referenceisthekeytounderstandingQoSconfiguration.Whereappropriate,thetaskcolumnin
Procedure 1onpage 21identifiesthesemappingrelationships.
See“DeterminingCoSPort‐Type”onpage 10and“ConfiguringCoSPortGroups”onpage 11for
aportgroupdiscussion.
Note: It is recommended that you use Enterasys NetSight Policy Manager as an alternative to CLI
for configuring policy-based CoS on the Enterasys Matrix Series devices.
A policy discussion is outside the scope of this document and will be limited to the relevant
configuration example commands.
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 10 of 29
Determining CoS Port-Type
Basedonphysicalcapability,allphysicalDFEportsbelongtooneoftwoport‐types.The
importanceofthisport‐typedistinctionliesintheresourcesavailableforTransmitQueueand
InboundRateLimitingCoSfeatures.Thenomenclaturedistinguishesthetypesasporttype0and
porttype1.TheEnterasysMatrixDFE7GR4270‐12,7G4270‐12,7G4270‐09,and7G4270‐10
moduleshaveaporttypeof0.Allothermoduleshaveaporttypeof1.
TxQ
Porttype0supportssixteentransmitqueues,whiletype1supportsfour.Usetheshowcos
port‐typetxqtodisplayallthesystemʹsportscurrentlyassociatedtoeachtype.
Thefollowingexampledisplaysdefaultvaluesfortheshowcosport‐typetxqcommandoutput:
IRL
Type0supportsthirty‐twoInboundRateLimiters,whiletype1supportseight.Usetheshowcos
port‐typeirlcommandtodisplaythetwoporttypesandtheirassociatedports.
Matrix(su)->show cos port-type txq
Number of resources: Supported rate types:
txq = transmit queue(s) perc = percentage
irl = inbound rate limiter(s) pps = packets per second
orl = outbound rate limiter(s) Kbps = kilobits per second
Mbps = megabits per second
Gbps = gigabits per second
Tbps = terabits per second
Number of
slices /
Port type Number of Supported Eligible Unselected
Index description queues rate type ports ports
----- ------------ --------- --------- ----------------- -----------------
0 DFE-P 16Q 64/16 perc ge.3.1-12; ge.3.1-12;
Kbps ge.4.1-9 ge.4.1-9
Mbps
Gbps
1 DFE-P 4Q 32/4 perc ge.1.1-18; ge.1.1-18;
Kbps fe.2.1-48; fe.2.1-48;
Mbps ge.5.1-60; ge.5.1-60;
Gbps ge.6.1-30; ge.6.1-30;
ge.7.1-30 ge.7.1-30
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 11 of 29
Thefollowingexampledisplaysdefaultvaluesfortheshowcosport‐typeirlcommandoutput:
Configuring CoS Port Groups
CoSportgroupsprovideforgroupingportsbyCoSfeatureconfigurationandporttype.Portsare
requiredtobeconfiguredbygroups:thisfeatureprovidesameaningfulwayofidentifyingports
bysimilarfunctionalityandporttype.
Groupsconsistofagroupnumberandporttypeandarenumberedassuch,port‐group.port‐type.
Forexample:portgroup0,porttype1wouldbenumberedportgroup0.1.Twodefaultport
groupsexistforbothTxQandIRLCoSfeaturesandareidentifiedasportgroup0andporttype0
or1andareindexedas0.0and0.1,respectivelyforeachfeature.Thesedefaultportgroupscannot
beremovedandallphysicalportsinthesystemareassignedtooneofthetwoportgroupsfor
eachfeature(remembergroupassignmentisdeterminedbyporttype).
Additionalportgroupsmaybecreated.Portsassignedtoanewportgroupcannotbelongto
anothernon‐defaultportgroupentryandmustbecomprisedofthesameporttypeasdefinedby
theportgroupyouareassociatingitwith.Thecreationofadditionalportgroupscouldbeusedto
combinesimilarportsbytheirfunctionforflexibility.Forinstance,portsassociatedtouserscanbe
addedtoaportgroupcalledUsersandportsassociatedtouplinkportscanbeaddedtoaport
groupcalledUplink.Usingtheseportgroups,aclassofserviceuniquetoeachgroupcanassign
differentratelimitstoeachportgroup.Userportscanbeassignedaratelimitconfiguredinone
CoS,whileUplinkportscanbeassignedadifferentratelimitconfiguredinanotherCoS.A
maximumof8portgroupsperCoStransmitqueueand/orrate‐limiterfunctionaresupported.
Matrix(su)->show cos port-type irl
Number of resources: Supported rate types:
txq = transmit queue(s) perc = percentage
irl = inbound rate limiter(s) pps = packets per second
orl = outbound rate limiter(s) Kbps = kilobits per second
Mbps = megabits per second
Gbps = gigabits per second
Tbps = terabits per second
Port type Number of Supported Eligible Unselected
Index description limiters rate type ports ports
----- ------------ --------- --------- ----------------- -----------------
0 DFE-P 32 IRL 32 irl perc ge.3.1-12; ge.3.1-12;
pps ge.4.1-9 ge.4.1-9
Kbps
Mbps
Gbps
1 DFE-P 8 IRL 8 irl perc ge.1.1-18; ge.1.1-18;
pps fe.2.1-48; fe.2.1-48;
Kbps ge.5.1-60; ge.5.1-60;
Mbps ge.6.1-30; ge.6.1-30;
Gbps ge.7.1-30 ge.7.1-30
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 12 of 29
Port-Groups: TxQ Configuration
TxQPort‐Groupscontainusersettingsforspecifictypesofportsandtheirmatchingtransmit
queuesettings.Portgroups0.0and0.1existbydefault.Newportgroupscanbeconfiguredwitha
nameandportscanbeaddedaccordingtodeviceport‐type.Transmitqueuebehaviorcanalsobe
configuredperportgroup;port‐groups0.0and0.1areconfiguredinstrictqueuingmode.
Additionalportgroupsalsodefaulttostrictqueuingmode,thougheachTxQportgroupcanbe
configuredforweighted‐fairqueuingifdesired.
Theshowcosport‐configtxqcommanddisplaysallconfiguredTxQport‐groups.Groupname
andtypearedisplayedaswellasportsassociatedwiththeportgroup.Forshowcosport‐config
txqoutput,arbitermode(TxQmode)isdisplayedalongwithapictureofthesupportedqueues
andthenumberofslicesallottedtothegroup.Queuingisalsodisplayedbypercentage.
Thefollowingexampledisplaysdefaultvaluesfortheshowcosport‐configtxqcommandoutput:
Additionalportgroupscanbecreatedusingthesetcosport‐configtxqcommand.Nameand
associatedportscanbeconfigured,aswellasTxQsettings.Youneedto:
•Identifytheport‐groupforconfiguration
Matrix(su)->show cos port-config txq
* Percentage/queue (if any) are approximations based on
[(slices/queue) / total number of slices]
Transmit Queue Port Configuration Entries
----------------------------------------------------------------------
Port Group Name :DFE-P 16Q
Port Group :0
Port Type :0
Assigned Ports :ge.3.1-12;ge.4.1-9
Arbiter Mode :Strict
Slices/queue :Q [ 0]: 0 Q [ 1]: 0 Q [ 2]: 0 Q [ 3]: 0
:Q [ 4]: 0 Q [ 5]: 0 Q [ 6]: 0 Q [ 7]: 0
:Q [ 8]: 0 Q [ 9]: 0 Q [10]: 0 Q [11]: 0
:Q [12]: 0 Q [13]: 0 Q [14]: 0 Q [15]: 64
Percentage/queue :Q [ 0]: 0% Q [ 1]: 0% Q [ 2]: 0% Q [ 3]: 0%
:Q [ 4]: 0% Q [ 5]: 0% Q [ 6]: 0% Q [ 7]: 0%
:Q [ 8]: 0% Q [ 9]: 0% Q [10]: 0% Q [11]: 0%
:Q [12]: 0% Q [13]: 0% Q [14]: 0% Q [15]: 100%
----------------------------------------------------------------------
Port Group Name :DFE-P 4Q
Port Group :0
Port Type :1
Assigned Ports :ge.1.1-18;fe.2.1-48;ge.5.1-60;ge.6.1-30;ge.7.1-30
Arbiter Mode :Strict
Slices/queue :Q [ 0]: 0 Q [ 1]: 0 Q [ 2]: 0 Q [ 3]: 32
Percentage/queue :Q [ 0]: 0% Q [ 1]: 0% Q [ 2]: 0% Q [ 3]: 100%
----------------------------------------------------------------------
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 13 of 29
• Optionally,specifyport‐groupName,associatedports,andarb‐percentageorarb‐slices
Port-Groups: IRL Configuration
IRLPort‐Groupscontainusersettingsforspecifictypesofportsandtheirmatchinginboundrate
limitingconfigurations.Portgroups0.0and0.1existbydefault.Eachnewgroupcanbe
configuredwithanameandportsaddedtoeachgroupaccordingtodeviceport‐type.Usethe
showcosport‐configirlcommandtodisplayeachIRLport‐groupconfiguredbygroupandtype,
withgroupnameandassociatedports.
Thefollowingexampledisplaysdefaultvaluesfortheshowcosport‐configirlcommandoutput:
Additionalportgroupscanbecreatedusingthesetcosport‐configirlcommand.Portgroup
nameandassociatedportscanbeconfigured.Youneedto:
•Identifytheport‐groupforconfiguration
• Optionally,specifyport‐groupNameandassociatedports
Configuring CoS Port-Resource
PhysicalratelimitersandrateshapersareconfiguredinCoSportresources.Resourcesmap
directlytothenumberofqueuesandratelimiterssupportedbyeachport‐type.Remember,group
0.0supports16TxQresourcesand32IRLresourceswhilegroup0.1supports4TxQresourcesand
8IRLresources.Resourcesexistforeachportgroupandareindexedasport‐group.port‐type
resource‐index.Port‐resourcesinitiallydefaulttonone,asratelimitingandshapingisnotrequired.
CoS TxQ Port-Resource (Outbound Rate Shapers)
Rateshapingthrottlestherateatwhichqueuestransmitpackets.SeeRateShapingonpage 8fora
generaldiscussionofrateshaping.RateshapingisTCPfriendly;itbufferspacketsthatareabove
therateratherthandropthem.CoSrateshapingallowsyoutoconfigurerateshapersbasedona
unitrate(kilobits/second,megabits/second,gigabits/second),orapercentageoftheport’sline
speed.
Theshowcosport‐resourcetxqcommanddisplaysresourcesforeachportgroupcreatedalong
withtheresourceindex(physicalqueue).Bydefault,noresourcesareconfiguredforTxQ
port‐resources.Ratesdisplayedasnoneindicatenoresourcesexist.ThedefaultRateShaping
algorithmistail‐dropandisnotconfigurable.
Matrix(su)->show cos port-config irl
Inbound Rate Limiting Port Configuration Entries
----------------------------------------------------------------------
Port Group Name :DFE-P 32 IRL
Port Group :0
Port Type :0
Assigned Ports :ge.3.1-12;ge.4.1-9
----------------------------------------------------------------------
Port Group Name :DFE-P 8 IRL
Port Group :0
Port Type :1
Assigned Ports :ge.1.1-18;fe.2.1-48;ge.5.1-60;ge.6.1-30;ge.7.1-30
----------------------------------------------------------------------
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 14 of 29
Thefollowingexampledisplaysdefaultvaluesfortheshowcosport‐resourcetxqcommand
output:
Thesetcosport‐resourcetxqcommandisusedforcreatingoutboundrateshapers.Youneedto:
•Identifytheportgroupforconfiguration
•IdentifythequeueresourceID,alongwithunitandratedesiredforthatqueue
CoS IRL Port-Resource (Inbound Rate Limiter)
Unlikerateshaping,inboundratelimitingorratepolicingsimplydropsorclipstrafficinboundif
aconfiguredrateisexceeded.See“RateLimiting”onpage 7forageneraldiscussionofrate
limiting.CoSinboundratelimitingallowsyoutoconfigureratelimitsbasedonaunitrate
(kilobits/second,megabits/second,gigabits/second),orpercentageoftheport’slinespeed.TheIRL
port‐resourceconfigurationallowsyoutoenablesendingsyslogmessagesortrapsoncearate
limitisexceeded,aswellastodisabletheport.
Theshowcosport‐resourceirlcommanddisplaysresourcesforeachportgroupcreatedalong
withtheindex,asdescribedabove.Bydefault,noresourcesareconfiguredforIRLport‐resources.
Ratesdisplayedasnoneindicatenoresourcesexist.ThedefaultRateLimitingalgorithmis
tail‐drop.TheActionfieldinthedisplayindicatesuser‐desiredactionforeachsyslog,trap,and
portdisablebehaviorwhenconfigured.
Thefollowingexampledisplaysdefaultvaluesfortheshowcosport‐resourceirlcommand
output:
Matrix(su)->show cos port-resource txq
'?' after the rate value indicates an invalid rate value
Group Index Resource Type Unit Rate Algorithm
----------- -------- ---- ---- ---------- ---------
0.0 0 txq perc none tail-drop
0.0 1 txq perc none tail-drop
0.0 2 txq perc none tail-drop
0.0 3 txq perc none tail-drop
0.0 4 txq perc none tail-drop
0.0 5 txq perc none tail-drop
0.0 6 txq perc none tail-drop
0.0 7 txq perc none tail-drop
0.0 8 txq perc none tail-drop
0.0 9 txq perc none tail-drop
0.0 10 txq perc none tail-drop
0.0 11 txq perc none tail-drop
0.0 12 txq perc none tail-drop
0.0 13 txq perc none tail-drop
0.0 14 txq perc none tail-drop
0.0 15 txq perc none tail-drop
0.1 0 txq perc none tail-drop
0.1 1 txq perc none tail-drop
0.1 2 txq perc none tail-drop
0.1 3 txq perc none tail-drop
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 15 of 29
Thesetcosport‐resourceirlcommandisusedforcreatinginboundratelimiters.Youneedto:
•Identifytheportgroupforconfiguration
•IdentifythelimiterresourceID,alongwithdesiredunit,rate,andactions
Configuring CoS Reference Mapping
TheCoSReferenceTablemapstheTxQandIRLreferences,definedbyyouandconfiguredinthe
CoSSettingsTable,tophysicalqueuesandratelimiterscreatedintheport‐resourcetable.ACoS
referencetableexistsforeachportgroup.TheCoSreferencetableindexescanbethoughtofas
virtualqueuesorratelimiters.Thetableaccountsforthemaximumnumberofqueuesandrate
limiterssupportedbythedevice.Thevirtualqueuesandlimitersmaptothephysicalqueuesand
ratelimiters.TheTxQReferenceTableispopulatedbydefault,becausequeuesarerequiredfor
allforwarding.TheTxQreferencemapseachreferencevaluetoaphysicalqueue.TheIRL
ReferenceTableisnotconfiguredbydefault,becauseinboundratelimitingisoptional.
CoS TxQ Reference Mapping
TheCoSTxQreferencetableuses16indexesorvirtualqueues,andmapseachtoaphysicalqueue
orresource.ATxQreferencetableexistsforeachportgroupconfiguredandisindexedsimilarly
toport‐resources,asport‐group.port‐typereference.Forport‐typeswith16queues,the16‐txq
referenceindexesmapdirectlytothe16physicalqueues.Forport‐typeswith4queues,the16‐txq
referenceindexesmap:
solutions-r1(su)->show cos port-resource irl
'?' after the rate value indicates an invalid rate value
Group Index Resource Type Unit Rate Rate Limit Type Action
----------- -------- ---- ---- ---------- --------------- ------
0.0 0 irl perc none drop none
0.0 1 irl perc none drop none
0.0 2 irl perc none drop none
0.0 3 irl perc none drop none
.
.
.
0.0 26 irl perc none drop none
0.0 27 irl perc none drop none
0.0 28 irl perc none drop none
0.0 29 irl perc none drop none
0.0 30 irl perc none drop none
0.0 31 irl perc none drop none
0.1 0 irl perc none drop none
0.1 1 irl perc none drop none
0.1 2 irl perc none drop none
0.1 3 irl perc none drop none
0.1 4 irl perc none drop none
0.1 5 irl perc none drop none
0.1 6 irl perc none drop none
0.1 7 irl perc none drop none
No violators exist for this/these irl(s)
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 16 of 29
•virtualqueues12‐15tophysicalqueue3
•virtualqueues8‐11maptophysicalqueue2
•virtualqueues4‐7maptophysicalqueue1
•virtualqueues0‐3maptophysicalqueue0
TheTxQreferencetablecanbedisplayedusingtheshowcosreferencetxqcommandand
displaysport‐group,referenceindex,andphysicalqueue.
Thefollowingexampledisplaysdefaultvaluesfortheshowcosreferencetxqcommandoutput:
AlthoughtheTxQreferencetableispopulatedbydefault,theQueue‐to‐Referencemappingcan
beconfiguredusingthesetcosreferencetxqcommand.Youneedto:
•Identifytheportgroupforconfiguration
•Identifythetransmitqueuereference,alongwiththeassociatedqueue
Matrix(su)->show cos reference txq
Group Index Reference Type Queue
----------- --------- ---- ------------
0.0 0 txq 0
0.0 1 txq 1
0.0 2 txq 2
0.0 3 txq 3
0.0 4 txq 4
0.0 5 txq 5
0.0 6 txq 6
0.0 7 txq 7
0.0 8 txq 8
0.0 9 txq 9
0.0 10 txq 10
0.0 11 txq 11
0.0 12 txq 12
0.0 13 txq 13
0.0 14 txq 14
0.0 15 txq 15
0.1 0 txq 0
0.1 1 txq 0
0.1 2 txq 0
0.1 3 txq 0
0.1 4 txq 1
0.1 5 txq 1
0.1 6 txq 1
0.1 7 txq 1
0.1 8 txq 2
0.1 9 txq 2
0.1 10 txq 2
0.1 11 txq 2
0.1 12 txq 3
0.1 13 txq 3
0.1 14 txq 3
0.1 15 txq 3
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 17 of 29
CoS IRL Reference Mapping Table
TheCoSIRLreferencetableuses32indexesorvirtualratelimiters,andmapseachvirtuallimiter
toaphysicallimiterorresource.AnIRLreferencetableexistsforeachportgroupconfigured,and
isindexedsimilarlytoport‐resources,asport‐group.port‐typereference.Becauseitisanoptional
configuration,IRLreferencesarenotpopulatedwithlimiters(resources),butcanbeconfiguredby
you.TheIRLreferencetablecanbedisplayedusingtheshowcosreferenceirlcommand.
Thefollowingexampledisplaysdefaultvaluesfortheshowcosreferenceirlcommandoutput:
Physical‐Limitertoreferencemappingcanbeconfiguredusingthesetcosreferenceirlcommand.
Theotherreferencesnotconfiguredareindicatedbyratelimiter“none”.Youneedto:
•Identifytheportgroupforconfiguration
•Identifytherate‐limitreference
Configuring the CoS Index
TheCoSsettingstableassignsapriority,aToSvalue,TxQreferenceandanIRLreferencetoaCoS
entryasfollows:
CoSIndex‐IndexesareuniqueIDsforeachCoSsettingstableentry.CoSindexes0–7arecreated
bydefaultandmappeddirectlytoan802.1ppriorityvalues0–7forbackwardscompatibility.
Theseentriescannotberemovedandthe802.1pvaluecannotbechanged.WhenCoSisenabled
usingthesetcosstateenablecommand,indexesareassigned.Entries0–255areconfigurablefora
totalof256CoSentries.
solutions-r1(su)->show cos reference irl
Group Index Reference Type Rate Limiter
----------- --------- ---- ------------
0.0 0 irl none
0.0 1 irl none
0.0 2 irl none
0.0 3 irl none
.
.
.
0.0 27 irl none
0.0 28 irl none
0.0 29 irl none
0.0 30 irl none
0.0 31 irl none
0.1 0 irl none
0.1 1 irl none
0.1 2 irl none
0.1 3 irl none
.
.
.
0.1 27 irl none
0.1 28 irl none
0.1 29 irl none
0.1 30 irl none
0.1 31 irl none
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 18 of 29
Priority:ForeachnewCoSindexcreated,youhavetheoptiontoassignan802.1ppriorityvalue
0‐7fortheclassofservice.CoSindexes0‐7mapdirectlyto802.1pprioritiesandcannotbechanged
astheyexistforbackwardcompatibility.AllotherCoSindexentriescanhaveapriorityvalueset
between0and7.
ToS:TheIPheaderTypeofServicefieldisan8‐bitfieldalsoreferredtoastheDiffServCodePoint
(DSCP)field.Thisoptionalvaluecanbesetperclassofservicetoavaluebetween0–255.Whena
frameisassignedtoaclassofserviceforwhichthisvalueisconfigured,theToSfieldofthe
incomingIPpacketwillbeoverwrittentovaluesdefinedbyyou.ThisToSrewriteoptionalso
allowsmasking.TheToScanselectivelymask(change)certainbitsofthefield,withoutchanging
others.ForinstancemaskingtheToScouldbeusedtomodifytheToSprecedencewithout
modifyingtheDTR/ECNbits.Themaskspecifiedcontainsthebitstobechanged.CLIinputcanbe
indecimalorhexvalue,andamaskisnotrequired.IfthemaskisnotspecifiedintheToSinput,all
bitswillbeoverwritten.ToScanbesetforCoSindexes0‐7.
TxQReference:Becausealltrafficrequiresassociationtoatransmitqueue,theCoSTxQreference
fieldwillalwaysbepopulatedwhenanewCoSindexiscreated.IfaTxQreferencevalueisnot
chosen,TxQreference0willbeassigned.Thereferencedoesnotindicatetheactualtransmit
queuetobeassignedbyCoS;itpointstotheCoSTxQReferenceMappingTableIndexentry.It
maybethoughtofasthevirtualqueuethatisassociatedtoaphysicalqueuedefinedbytheTxQ
ReferenceMappingTable.TxQReferenceMappingTabledefines16TxQreferences,thereforeCLI
inputforTxQreferenceintheCoSSettingsTableis0‐15.See“CoSTxQReferenceMapping”on
page 15foraTxQreferenceconfigurationdiscussion.
IRLReference:TheCoSIRLreferencefieldisoptional,asratelimitsarenotrequired.Likethe
TxQreferencefield,theIRLreferencedoesnotassignaninboundratelimitbutpointstotheCoS
IRLReferenceMappingTable.Thisreferencemayalsobethoughtofasthevirtualratelimiterthat
willassignthephysicalratelimiterdefinedbytheIRLReferenceMappingTable.TheIRL
ReferenceMappingTabledefines32IRLreferences,thereforeinputforIRLreferenceintheCoS
SettingsTableis0‐31.See“CoSIRLReferenceMappingTable”onpage 17foranIRLreference
configurationdiscussion.
NewCoSIndexescanbecreatedusingthesetcossettingscommand.ToS,802.1ppriority,TxQ
reference,andIRLReferencecanbeconfiguredforeachCoSIndex.Youneedto:
•EnteraCoSIndexvaluefrom0–255
•Specify802.1ppriority(Indexentries8–255only),tos‐value,txq‐referenceandirl‐reference
UsethesetcossettingscommandtocreateormodifyanalreadyexistingCoSindex.
UsetheshowcossettingscommandtodisplaycurrentCoSindexes.
Understanding QoS Configuration on the Matrix N-Series
February 22, 2008 Page 19 of 29
Thefollowingexampledisplaysdefaultvaluesfortheshowcossettingscommandoutput:
Enabling CoS State
CoSstateisaglobalsettingthatmustbeenabledforCoSconfigurationstobeappliedtoaport.
WhenCoSstateisenabled,controlsconfiguredforCoSsupersedeportlevelcontrolsforpriority
queuemapping,IRL,andTxQ.TheseportlevelsettingscanbeconfiguredindependentofCoS
state,butwillhavenoaffectwhileCoSisenabled.DisablingCoSresultsintherestorationof
currentportlevelsettings.
UsethesetcosstateenablecommandtoenableCoSstategloballyforthissystem.
UsethesetcosstatedisablecommandtodisableCoSstategloballyforthissystem.
UsetheshowcosstatecommandtodisplaythecurrentstatusofCoSstate.
Displaying CoS IRL Violation
IRLviolationscanbedisplayedperphysicalratelimittoshowyouwhenaninboundratelimithas
beenviolated.Usetheshowcosviolationirlcommandtodisplayportsthathavealimiter
violatedaswellasanyportsthatmaybedisabledbythelimiter.
Matrix(su)->show cos settings
* Means attribute has not been configured
CoS Index Priority ToS TxQ IRL
--------- ---------- ------- ----- -----
0 0 * 0 *
1 1 * 2 *
2 2 * 4 *
3 3 * 6 *
4 4 * 8 *
5 5 * 10 *
6 6 * 12 *
7 7 * 14 *
Feature Differences
February 22, 2008 Page 20 of 29
Thefollowingexampledisplaysdefaultvaluesfortheshowcosviolationirlcommandoutput:
Violationsarealsodisplayedbyresourceandportusingtheshowcosport‐resourceirlcommand.
Violatingportsaredisplayedattheendoftheresourcetable.
Feature Differences
TheEnterasysSecureStackandstandalonesecureswitchdevicesdifferinCoSfeaturesetfromthe
N‐Seriesinthefollowingways:
•CoSTxQfeaturesarenotsupported.
•OnlytheIRLKbpsunitoptionissupported.
• Syslog,trap,andportdisableoptionsarenotsupported.
• Supports99IRLreferencesinsteadofthe32/8supportedbytheN‐Seriesporttypes0and1,
respectively.
•AllSecureStacksbelongtoportgroup0.0.Noporttype1existsfortheSecureStack.
•FortheC3,IRLconfigurationisonlysupportedwithinapolicyrolecontext.Configurationof
IRLswithinrulesarenotsupported.Inamixed‐stack,C3CoSfeaturelimitationsapply.
solutions-r1(su)->show cos violation irl
Rate-Limiter Rate-Limiter Rate-Limiter
Port Index Type Status Counter
------------ ------------ ---- ------------ --------------------
ge.1.1 0 irl not-violated 0
ge.1.1 1 irl not-violated 0
ge.1.1 2 irl not-violated 0
ge.1.1 3 irl not-violated 0
ge.1.1 4 irl not-violated 0
ge.1.1 5 irl not-violated 0
ge.1.1 6 irl not-violated 0
ge.1.1 7 irl not-violated 0
ge.1.2 0 irl not-violated 0
ge.1.2 1 irl not-violated 0
ge.1.2 2 irl not-violated 0
ge.1.2 3 irl not-violated 0
.
.
.
ge.7.29 5 irl not-violated 0
ge.7.29 6 irl not-violated 0
ge.7.29 7 irl not-violated 0
ge.7.30 0 irl not-violated 0
ge.7.30 1 irl not-violated 0
ge.7.30 2 irl not-violated 0
ge.7.30 3 irl not-violated 0
ge.7.30 4 irl not-violated 0
ge.7.30 5 irl not-violated 0
ge.7.30 6 irl not-violated 0
ge.7.30 7 irl not-violated 0
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