Zte ZXR10 5250 Series - Page 201

Chapter5ServiceConguration
AnRPLownernodeisanodeonanRPL.ItisusedtoblocktheportthathasRPL
enabled.
lRPLneighbornode(RPLneighbornode)
AnRPLneighbornodeisusedtoblockoneendofanRPL.TheotherendoftheRPL
isblockedbytheRPLownernode.
lManualswitchingcommands
TheERPSprotocolsupportstriggeringtheprotocolcalculationbyusingmanual
switchingcommands:ForcedSwitch(FS)andManualSwitch(MS).
lWTRtimer
Inrevertivemode,theWTRtimerisusedtopreventthefrequentoperationofthe
protectionswitchduetoanintermittentdefect.
lWTBtimer
Whenthecorrespondingfunctionofthedeviceisrestoredafteranoperationcommand
(suchastheFSorMScommand)isexecuted,thedelaytime(calledWTBtime,guard
timertimeplusveseconds)mustbesetlongenoughtoreceivepotentialFS,SF ,or
MSrequestsfromtheremoteend.ThistimeislongenoughforanEthernetring
nodetoconsecutivelysendtwoR-APSmessages,anditisalsotheconditionfor
determiningthattheEthernetringnodeexists.
Note:
TheWTBtimerisvalidfortheRPLownernodeonly,andthevaluerangedependson
theguardtimer.
lGuardtimer
TheguardtimerisusedtopreventexpiredR-APSpackets.
AnEthernetringnodecansendmultipleR-APSpacketssimultaneously.Inthiscase,
thenodecanstillsendexpiredR-APSpacketsuntilitreceivesanewR-APSpacket.
IftheringnodereceivesanR-APS(SF)packetthatisthesameasthemessage
previouslysentbythenode,thenodedeterminesthatanSFoccurs.Duetothe
abovereason,theguardtimerisusedtoforcedlypreventloops.
lRingstatuses
Aringmaybeinidle,pending,protection,FS,orMSstatus.
LinkSwitchingProcedureinERPS
ERPSeliminateslogicalloopsbyblockingsomeportsonthering.Whensomelinksinthe
ringhavetheirstatuschanged(fromuptodownorfromdowntoup),ERPScanswitcha
logicalpathimmediately.
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SJ-20131111172707-002|2013-11-27(R1.0)ZTEProprietaryandCondential