D-Link DWL-3600AP - Page 62

ModifyingRadioSettings
D-Link UnifiedAccessPointAdministrator’sGuide
November2011 Page62
UnifiedAccessPointAdministrator’sGuide
Protection Theprotectionfeaturecontainsrulestoguaranteethat802.11ntransmissionsdonot
causeinterferencewithlegacystationsorAPs.Bydefault,theseprotectionmechanisms
areenabled(Auto).Withprotectionenabled,protectionmechanismswillbeinvokedif
legacydevicesarewithinrangeoftheAP.Thiscausesmoreoverheadon
every
transmission,whichwillimpactperformance.However,thereisnoimpacton
performanceiftherearenolegacydeviceswithinrangeoftheAP.
Youcandisable(Off)theseprotectionmechanisms;however,when802.11nprotection
isoff,legacyclientsorAPswithinrangecanbeaffect edby802.11ntransmissions.The

802.11protectionfeatureisalsoavailablewhenthemodeis802.11b/g.When
protectionisenabledinthismode,itprotects802.11bclientsandAPsfrom802.11g
transmissions.
Note:ThissettingdoesnotaffecttheabilityoftheclienttoassociatewiththeAP.
BeaconInterval Beaconframesaretransmittedbyan
APatregularintervalstoannouncetheexistence
ofthewirelessnetwork.Thedefaultbehavioristosendabeaconframeonceevery100
milliseconds(or10persecond).
Enteravaluefrom20to2000milliseconds.
DTIMPeriod SpecifyaDTIMperiodfrom1to255beacons.
TheDeliveryTrafficInformationMap
(DTIM)messageisanelementincludedinsome
Beaconframes.Itindicateswhichclientstations,currentlysleepinginlow‐powermode,
havedatabufferedontheAPawaitingpick‐up.
TheDTIMperiodyouspecifyindicateshowoftentheclientsservedbythisAPshould
checkforbuff ereddatastillon
theAPawaitingpickup.
Themeasurementisinbeacons.Forexample,ifyousetthisfieldto1,clientswillcheck
forbuffereddataontheAPateverybeacon.Ifyousetthisfieldto10,clientswillcheck
onevery10thbeacon.
Fragmentation
Threshold
Specifyanumberbetween256
and2,346tosettheframesizethresholdinbytes.
Thefragmentationthresholdisawayoflimitingthesizeofpackets(frames)transmitted
overthenetwork.Ifapacketexceedsthefragmentationthresholdyouset,the
fragmentationfunctionisactivatedandthepack etissentasmultiple802.11frames.
If
thepacketbeingtransmittedisequaltoorlessthanthethreshold,fragmentationisnot
used.
Settingthethresholdtothelargestvalue(2,346bytes)effectivelydisables
fragmentation.FragmentationplaysnorolewhenAggregationisenabled.
Fragmentationinvolvesmoreoverheadbothbecauseoftheextraworkofdividingup
andreassemblingof
framesitrequires,andbecauseitincreasesmessagetrafficonthe
network.However,fragmentationcanhelpimprovenetworkperformanceandreliability
ifproperlyconfigured.
Sendingsmallerframes(byusinglowerfragmentationthreshold)mighthelpwithsome
interferenceproblems;forexample,withmicrowaveovens.
Bydefault,fragmentationisoff.Werecommendnot
usingfragmentationunlessyou
suspectradiointerference.Theadditionalheadersappliedtoeachfragmentincreasethe
overheadonthenetworkandcangreatlyreducethroug hput.
Table19:RadioSettings(Cont.)
Field Description