Zte ZXR10 5900E Series - Figure 11 ROOT BRIDGE

Chapter5STPConguration
stateafterMAX_AGEtime.PortinLOOP_INCONSISTENTstate
won’ttransmitdata.Thiswillavoidlooping.
PortRoot
Protection
Function
Portrootprotectionfunctionprovidesawaytoprotectrootswitch.
Inswitchenvironment,allswitcheswhichenablespanning-tree
willtakepartintheelectionofrootswitch.Switchwhichhas
thelowestprioritywillberootswitch.Afterelection,ifonenew
switchwhichhassmallerprioritythantherootswitchconnectsto
network,thisnewswitchwillreplacetheoriginalrootswitchto
becomenewrootswitch.Thisresultsincalculatingspanningtree
againandinterruptingnetworkforawhile.Thenewspanningtree
maycontainsub-optimumpathandlowernetworkperformance.
Here,let'sseehowportrootprotectionfunctionsolvesthisprob-
lem.
FIGURE11ROOTBRIDGE
InFigure11,switchAandswitchBarebothcoreswitchesand
switchAisarootswitch.SwitchCisaedgeswitch.Portofswitch
CwhichconnectstoswitchBisblocked.TheowofBPDUisas
directionofarrow.
CondentialandProprietaryInformationofZTECORPORATION43