User's Manual

CHAPTER7
BRIDGELINKSANDMESH
Revised: 27 Jun 16 7-4 ESTeem Horizon Series
RSTPPhases
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Thefollowingsectionsde scribetheprocessoftheRSTPintheESTeemHorizonashowitwouldhappenintheaboveexample.
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LearningPhase‐Once properlyconfigured,eachHorizonwillbegintosearchouttheotherHorizonunitsinradiorangethatare
programmedintheAPRepeaterPeertable.AllHorizon’swillcalculatetheirroutestoeveryHorizoninthenetworkbasedupon
thelowest“pathlength”totheRootBridge.Pathlengthisthetotalnumberofwirelesslinks(repeaterpeerlinks)totransmita
packetthroughthewirelessnetworktotheRootBridge.Note:TheRootBridgeinane
tworkshouldbetheHorizonwherethe
majorityofthedataflowisprocessed.Ineverywirelessnetworkoftwoormoreradios,theRootBridgeshouldbeuserdefined.
Ifnotdefined,theHorizonwiththelowestMACaddresswillbedesignatedastheRootBr
idge.
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InFigure4,thePlantnetwor k(Example1)isthemostlogicallocationfortheRootBridgebasedupontheamountofdata flow.
Settingthissi teastherootbridgeisdiscussedbelowinRoot Bridge.
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BlockingandForwardingPhase–Toensureyoudonothaveanetworkloopsi
tuationduetoredundantpathsinyourwireless
network,theModelHorizonwillrecognizeanddisable(block)oneormoreredundantlinksandprovidebackuplinksshouldthe
primarylinkfail.Thisestablishesawirelessmeshnetworkwithaseriesofforwardinglinks,basedupontheshortestpathlength
totheRootBridge.
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Forexample, lookingatFigure4,theRemoteBuild
inghastworoutestotheRootBridge (PlantNetwork–Example#1);directlyto
thesiteandthroughtherepeater.Thedirectlinkbetweenthetwositesistheshortestroute(lowestPathLength)andwillbe
selectedastheprimaryrouteunlessoverriddenbymanuallychangingthePathLengthintheconfiguration.
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PathCost
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Ifmorethanonecommun
icationpathtotheRootBridgeisfound,theHorizonmustdeterminewhichroutetotakebasedupon
thelowestPathCost.ThedefaultpathcosttoalllinksintheHorizonnetworkis1.IfthePathCostsareequalthenthelowe
st
MACaddresswilldeterminethepriorityroute.IntheESTeemMeshNetworkwewanttodirectlycontrolalldataflowsodonot
wantthero utes tobeautomaticallydetermined.
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LookingagainatourExampleinFigure4,ifwemadenochanges to thede
fault pathcostof1(notevaluesinFigure3)thelowest
pathcostwouldbe directfromthe RemoteBuildingtotheRootBridge(PlantNetwork).
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LinkDescription TotalPathLength
Directfro mRemoteBuilding 1
RemoteBuildtoRootBridgeThroughRepeater 2(Length1torepeater +Length1toMaster=2)
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ToconfiguretheHorizontoselecttherepeaterasthe primaryradiopath,setthepathcostvalueforthedirectlinkgreaterthan2
(suchasavalueof3)tomakethistheprimaryradiopath.Thelowestpathlengthwillidentifythehighestpriority.TheModel
Horizonwillusethisrout
ing,butalsoswitchtodirectcommunicationiftherepeaterweretodisappear.
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RootBridge
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InanyAccessPointRepeaternetworkconsistingofmorethantwosites,oneModelHorizonshouldbedesignatedastheRoot
Bridge.OnlyoneModelHorizoncanbedesignatedastheRootBridgeinagiv
ennetworkandshouldbelocatedwherethemajority
ofthe Ethernetdataflow isprocessed.Thissitemaybethe Masterlocation inaSCADAnetworkor cou ldbe configuredat a
repeatersite.SelectionisimportantbecauseallModelHorizon’sNOTconfiguredastheRootBridgewi
llchooseroutingbased
uponthePathLengthtotheRootBridge.IfyouhaveanyquestionastowhichsiteinyourAPRepeaterapplicationshouldbethe
RootBridge,contactESTeemCustomerSupportat509‐735‐9092ore‐mailyourapplicationto[e-mail].
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