Specifications

Quality of Service Overview
May 09, 2011 Page 7 of 38
Port Resources
UsetheCoSportresourceconfigurationlayertoassociateactualratelimitervaluestoaportgroup
andhardwareresource.ConfigureCoSportresourcebyidentifyingtheCoShardwareresource
type(TxQ,IRL,ORL,offloodcontrol),portgroup,andportresource,followedbyaratelimiter,or
inthecase
ofTxQ,arateshaper.
Theratelimitorrateshaperisspecifiedasaunitandadatarate.Theunitspecifieseithera
percentageofthetotalorapackets‐per‐secondvaluefollowedthethedatarateasanumericvalue.
Forexample10,000packets‐per‐second
wouldbeexpressedasunitppsrate10000 .The default
unitsettingispercentage.Ifonlyrateisspecif ied,theratevalueisapercentage.
•TxQ–SettingaTxQrateshapermeansthatallpacketsabovethespecifiedratelimitarefirst
buffered.Onlywhenthebufferfillsarepackets
dropped.
TxQratelimitingprovidesforsettingatail‐dropbehavior,bywhichtransmitframesare
discardedfromthetailofthequeue.
TxQrateshapingisdirectlyconfiguredusingCoSportresourcesconfiguration.TheCoS
settingandCoSreferenceconfigurationsdonotapplytoTxQrateshaping.
•IRL–Setting
anIRLratelimitermeansthatpacketsingressingtheportwillnotbeallowedto
exceedtheratespecifiedbytheratelimiter.Iftherateisexceeded,youcanspecifywhether
packetsthatexceedtheratelimitshouldbedroppedandwhethertheportshouldbedisabled.
Youcan
enableordisablesyslogandtrapfeatures.
IRLportresourcesarefirstreferencedusingtheCoSsettingsandCoSreference
configurations.PortsareappliedtothespecifiedCoSportresourcesusingtheCoSport
configuration.
•ORL–SettinganORLratelimitermeansthatoutboundpacketsabovethespecifiedthreshold
are
nottransmitted.Iftherateisexceeded,youcanspecifywhetherpacketsthatexceedthe
ratelimitshouldbedroppedandwhethertheportshouldbedisabled,andenableordisable
syslogandtrapfeatures.
ORLportresourcesarefirstreferencedusingtheCoSsettingsandCoSreference
configurations.Portsare
appliedtothespecifiedCoSportresourcesusingtheCoSport
configuration.
• Floodcontrol–Settingafloodcontrol ratelimitermeansthatreceivedpacketsofthespecified
typethatexceedthefloodcontrolthresholdwillbepreventedfromegressinganyport.
Configurablepackettypesare:
– unknown‐unicast
–multicast
–broadcast
Iftherateis
exceeded,youcanspecifywhethertheportshouldbedisabled.Youcanenableor
disablesyslogandtrapfeatures.
Port Configuration
TheCoSportconfigurationlayerappliesaportlisttotheportgroup.ConfigureCoSport
configurationbyidentifyingtheCoShardwareresourcetype(TxQ,IRL,ORL,orfloodcontrol)
andportgroupforthisportconfiguration,anameforthisconfiguration,aportlistofports
assignedtothisport
group,andwhethertheportlistshouldclearedorbeappendedtoany
existingportlist.TxQportconfigurationcanalsobeconfiguredforTxQscheduling.