Specifications

About QoS
12-10 Configuring Quality of Service
WMM QoS on a RoamAbout Access Point
RoamAboutAPsuseforwardingqueuestoprioritizetrafficforwirelessclients.
ForapacketreceivedbytheRoamAboutAPfromaclient,theAPclassifiesthepacketbasedon
theservicetypeinthe802.11headerandmapstheservicetypevaluetoan internalCoSvalue.The
APthenmarks
theDSCPvalueintheIPtunnelheadertotheRoamAboutSwitchbasedonthe
internalCoSvalue.
ForapacketreceivedfromaRoamAboutSwitchandaddressedtoaclient,theRoamAboutAP
classifiesthepacketbymappingtheDSCPvalueintheIPtunnelheadertoaninternalCoS
value.
TheAPthenassignsthepackettoaforwardingqueuebasedontheinternalCoSvalue.TheAP
alsomarkstheservicetypeinthe802.11headerbasedontheinternalCoSvalue.
ARoamAboutAPusestheDSCP‐to‐CoSandCoS‐to‐DSCPmappingsoftheRoamAboutSwitch

thatismanagingit.IfyouchangemappingsonaRoamAboutSwitch,thechangealsoappliesto
theAP.Likewise,ifaRoamAboutAPchangestoanotherRoamAboutSwitch(forexample,aftera
APrestart),theAPusesthemappingsineffectonthenewRoamAboutSwitch.
Table 12‐3liststhe
defaultmappingsbetweenaRoamAboutAPinternalCoSvaluesandits
forwardingqueues.
TodisplayaRoamAboutDAP’sCoSmappings andqueueusagestatistics,see“DisplayingAP
ForwardingQueueStatistics”onpage 12‐22.
Figure 12‐5showsanexampleofend‐to‐endQoSinaRoamAbout network.Inthisexample,
voice
trafficisprioritizedbasedonWMM.ThisexampleassumesthattheQoSmappingsaresettotheir
defaultvalues.
Table 12-3 Default CoS-to-AP-Forwarding-Queue Mappings
CoS AP Forwarding Queue
1 or 2 Background
0 or 3 Best Effort
4 or 5 Video
6 or 7 Voice