D-Link DWL-3600AP - Page 105

ConfiguringQualityofService
D-Link UnifiedAccessPointAdministrator’sGuide
November2011 Page105
UnifiedAccessPointAdministrator’sGuide
Station EDCA Parameters
Queue Queuesaredefinedfordifferenttypesofdatatransmittedfromstation‐to‐AP:
• Data0(Voice)—Highestpriorityqueue,minimumdelay.Time‐sensitivedata
suchasVoIPandstreamingmediaareautomaticallysenttothisqueue.
• Data1(Video)—Highestpriorityqueue,minimumdelay.Time‐sensitivevideo
datais
automaticallysenttothisqueue.
• Data2(besteffort)—Mediumpriorityqueue,mediumthroughputanddelay.
MosttraditionalIPdataissenttothisqueue.
• Data3(Background)—Lowestpriorityqueue,highthroughput.Bulkdatathat
requiresmaximumthroughputandisnottime‐sensitiveissenttothisqueue

(FTPdata,forexample).
AIFS
(Inter‐FrameSpace)
TheArbitrationInter‐FrameSpacing(AIFS)specifiesawaittimefordataframes.
Thewaittimeismeasuredinslots.ValidvaluesforAIFSare1through255.
cwMin
(MinimumContention
Window)
Thisparameterisusedbythealgorithmthatdeterminestheinitialrandom
backoff
waittime(window)forretryofadatatransmissionduringaperiodofcontentionfor
UnifiedAccessPointresources.ThevaluespecifiedhereintheMinimumContention
Windowistheupperlimit(inmilliseconds)ofarangefromwhichtheinitialrandom
backoffwaittimewillbedetermined.Thefirst
randomnumbergeneratedwillbea
numberbetween0andthenumberspecifiedhere.Ifthefirstrandombackoffwait
timeexpiresbeforethedataframeissent ,aretrycounterisincrementedandthe
randombackoffvalue(window)isdoubled.Doublingwillcontinueunti lthesizeof
therandom
backoffvaluereachesthenumberdefinedintheMaximumContention
Window.
cwMax
(MaximumContention
Window)
ThevaluespecifiedhereintheMaximumContentionWindowistheupperlimit(in
milliseconds)forthedoublingoftherandombackoffvalue.Thisdoublingcontinues
untileitherthedataframeissentortheMaximum
ContentionWindowsizeis
reached.
OncetheMaximumContentionWindowsizeisreached,retrieswillcontinueuntila
maximumnumberofretriesallowedisreached.
TXOPLimit TheTXOPLimitisastationEDCAparameterandonlyappliestotrafficflowingfrom
theclientstationtotheAP.TheTransmissionOpportunity(TXOP)
isanintervalof
time,inmilliseconds,whenaWMEclientstationhastherighttoinitiate
transmissionsontothewirelessmedium(WM)towardstheUnifiedAccessPoint.
TheTXOPLimitmaximumvalueis65535.
Other QoS Settings
NoAcknowledgement SelectOntospecifythattheAPshouldnotacknowledgeframeswithQosNoAckas
theserviceclassvalue.
APSD SelectOntoenableAutomaticPowerSaveDelivery(APSD),whichisapower
managementmethod.APSDisrecommendedifVoIPphonesaccessthenetwork
throughtheAP.
Note:Afte ryouconfiguretheQoSsettings,youmustclickApplytoapplythechangesandtosavethe
settings.ChangingsomesettingsmightcausetheAPtostopandrestartsystemprocesses.Ifthis
happens,wirelessclientswilltemporarilyloseconnectivity.WerecommendthatyouchangeAP
settingswhenWLAN
trafficislow.
Table40:QoSSettings(Cont.)
Field Description