Zte ZXR10 2900E Series - Page 220

ZXR102900ESeriesCongurationGuide
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.
AsshowninFigure5-68andFigure5-69,anERPSdomainisconguredonswitchesA,
B,C,andD.SwitchAistheownernode,anditsport1/2isanRPLport.SwitchBisthe
neighbornode.TheportthatswitchBusestoconnecttoswitchAisalsoanRPLport.
BothswitchCandswitchDarenonenodes.
ServicetrafcarisesbetweenPC1andPC2,andthearrowsinFigure5-68indicatethe
directioninwhichservicedataows.
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SJ-20130731155059-002|2013-11-27(R1.0)ZTEProprietaryandCondential