Radwin Transportation FiberinMotion - Page 68

FinMDeploymentGuide Release4.5.10 3‐2
WaysideNetwork NetworkGuidelines
• Thebackhaulnetwork(existingorprovidedbythesystemintegrator/customer)isused
toaggregatetrafficto/fromtheTBSsandsendittothecontrol/datacentres.
• Therequirednetworkarchitecturemusthaveasinglecorerouter,andL2switches.All
datacommunicationto/fromthetrainwillpassviathisrouter.
• AredundantISU/OSUisprovidedtoensurehigherresiliencyofthesolution.
• TheTBS'snetworkissynchronizedeitherviaGPS‐basedsystem(forabovegroundsce‐
narios)orviaEthernet ‐basedsynchronization(foraboveorundergroundscenarios).
• ForGPSbasedsynchronization,theTBSintegratedGPSSynchronizationUnitisused.
• ForEthernet‐basedsynchronization,theTBS'snetworkissynchronizedbyEthernet
basedsynchronization,runningoverthesamedatabackhaulnetwork.Theimplementa‐
tionofthesynchronizationprotocolisviaanIndoorSynchronizationUnit(ISU)orOut‐
doorSynchronizationUnit(OSU)thatisconnectedtooneofthenetworkswitches,and
providesthemasterclocktoallTBSsinthenetwork.
• ISUsworkusingastartopology,whileOSUsworkusingaringtopology.
• Thesynchronizationarchitecturemayvarydependingonthespecificnetworktopology,
soRADWINneedstoevaluateandapprovethewaysidenetworktopologyandassureit
willsupportthesynchronizationprotocol.Typicalsynchronizationrequirements
include:
• Layer2connectionbetweenallISU/OSUsandTBSs.
• Maximumof4switchesbetweenISU/OSUsandeachTBS.
• Avoidhighlinespeedutilizationtopreventintroductionofjitterandlatency.The
lineloadshouldbelimitedaccordingtothefollowingtable:
• Networkswitchesshouldappropriatelyhandlethesystem'srelearningframes.These
framesareVLANtagged(802.1Q).Switchshouldforwardtherelearningtrafficand
updateFIB(ForwardingInformationBase).
• IEEE802.3azmustbedisabledonallswitches.
• Spanningtreebetweentrainandwaysideisnotsupportedandmustbedisabledon
switchportsconnectedtotheRADWINradios(bothTBSsandTMUs).
• Staticroutingshouldbeimplementedbetweenwaysidecorerouterandon‐boardrout‐
ers.ImplementationofdynamicroutingprotocolsshouldbeconfirmedwithRADWIN
professionalservices.
Table3‐1:ISU/OSU‐TBSswitchesvs.lineutilization
NumberofSwitches
BetweenISU/OSUandTBS
MaximalLineUtilization
195%
285%
3 75%
465%