D-Link DWS-4026 [698/741] Optimizing wlan traffic

OptimizingWLANTraffic

D-Link UnifiedWiredandWirelessAccessSystem

November2011 Page698

D‐LinkUWSUserManual

OptimizingWLANTraffic

TheUnifiedWiredandWirelessAccessSystemincludesfeaturesthatautomaticallyhelptooptimizewireless

trafficonthenetwork.Thissectiondescribesthefollowingfeatures:

•Automaticchannelselectionandadjustmentonaccesspointradios

•AutomaticpoweradjustmentforaccesspointRFtransmissionpowerlevels

•Per‐radioloadbalancingtosetthemaximumutilizationthr

eshold

Bydefault,theautomaticchannelselection,automaticchanneladjustment,andautomaticpoweradjustment

featuresareenabledbutrequiremanualtriggerstorun.Loadbalancingisdisabledbydefault.Thissection

describeswaystomonitorthechannelandpoweroftheAPandtomakemanualadjustments,ifnecessary.It

alsode

scribeshowtoenabletheloadbalancingfeatureandmonitorWLANutilization.Thissectionassumes

thattheswitchhasbeenconfiguredandiscurrentlymanagingmultipleAPs.

MonitoringandManagingChannelInformation

Interferencecanoccurwhenmultipleaccesspointswithinrangeofeachotherarebroadcastingonthesame

oroverlappingchannels.Theimpactofthisinterferenceonnetworkperformancecanintensifyduringbusy

timeswhenalargeamountofdataandmediatrafficiscompetingforbandwidth.WhenAPsarewithin

broadcastra

ngeofeachother,theradiosmustusedifferentchannelstoavoidcausingRFinterference.Forthe

802.11b/gradio,neighboringAPsmustoperateonchannelsthatareatleastfivechannelsapart.Forexample,

ifAP1andAP2areneighbors,AP1canoperateonchannel6whileAP2operat esonchannel11.Channelsin

the5GHzband(80

2.11a/n)donotoverlap,sothesechannelsinterfereonlyifneighboringAPsoperateonthe

samechannel.

ToavoidinterferencewithneighborAPs,theUnifiedWiredandWirelessAccessSystemusesanInitialChannel

Selection(ICS)algorithm.WhentheAPispowereduptheISIalgo

rithmscansalltheavailablechannelsand

countsthenumberofpacketsreceivedoneachchannel.Thebestoperatingchannelisconsideredtobethe

onewiththelowestpacketcount,andthischannelisassignedtotheAPradio.

ToviewthechannelsthatareassignedtomanagedAPs,clickWLAN>Monit

oring>AccessPoint>Managed

APStatus.AsFigure439onpage699shows,Radio1(802.11a/n)onAP_1isoperatingonchannel157,Radio

1onAP_2isoperatingonchannel44,andRadio1onAP_3isoperatingonchannel36.Radio2(802.11b/g/n)

onAP_1isoper

atingonchannel1,Ra dio2onAP_2isoperatingonchannel6,andRadio2onAP_3isoperating

onchannel11.Forbothradios,theoperatingchannelsforAP_1donotinterferewiththeoperatingchannels

forAP_2.