Zte ZXR10 2900E Series - Figure 5-38 Diagram of the Master Node Opening Its Secondary Port When the Ring Is in down State

ZXR102900ESeriesCongurationGuide
Figure5-38DiagramoftheMasterNodeOpeningitsSecondaryPortWhentheRing
isinDOWNState
AsshowninFigure5-37,alllinksoperateproperly,theringisinUPstate,thesecondary
portofthemasternodeisblocked,andtrafcneedstogothroughswitchCandswitchD.
AsshowninFigure5-38,thelinkbetweenswitchBandswitchCisdisconnected,thering
stateischangedtoDOWN,ZESRrapidlytransitsthesecondaryportofthemasternode
toForwardingstate,andtrafcisswitchedquicklytoswitchAwithoutgoingthroughswitch
CandswitchD.
WhenthelinkbetweenswitchBandswitchCrecoversfromdisconnection,thesecondary
portofthemasternodeisblockedagain,theringisswitchedtoUPstate,andtheentire
ZESRregionreturnstothestateshowninFigure5-37.
link-helloLinkConnectivityDetectionOverview
Figure5-39showsthetransmissionlinkfaultdiagram.SwitchCdoesnothaveadirect
connectionwithswitchD.Theyareinterconnectedwitheachotherthroughtransmission
links.
Whenthetransmissionlinkmarkedinredinthemiddleofthetransmissionlinks
encountersabidirectionalconnectivityfailure,switchCandswitchDarestillinUPstate.
Ifthebidirectionalconnectivitydetectionfunctionisnotenabledforthetransmissionlink,
switchCandswitchDwillnotbeabletoperceivethisfailureandforthisreasonZESR
linkswitchingwillnotbetriggered.
Ifthelink-hellolinkconnectivitydetectionfunctionisenabledontheportsthroughwhich
switchCandswitchDareinterconnectedwitheachother,theseportswillperiodicallysend
link-hellodetectionpacketstoeachother.Ifaportdoesnotreceivethelink-hellodetection
packetfromthepeerportwithinaspeciedtimeperiod,theswitchwillconsiderthisasa
linkfailure.Thedevicewillimmediatelyblocktheportsonthelinkandinformthemaster
nodetoimplementlinkswitching.
5-110
SJ-20130731155059-002|2013-11-27(R1.0)ZTEProprietaryandCondential