Zte ZXR10 2900 Series - Figure 49 MSTP Topological Structure

Chapter7ServiceConguration
covermanyMSTareas.UsercandividetheswitchesintoaMST
areabyusingMSTPcommands.
�Sameareaname.
�Samereversionlevel.
�SamemappingrelationshipbetweenVLANandinstance.
�Switchesshouldbeconnecteddirectly.
TherearemanyspanningtreescanbeconguredineachMSTP
area,andtheyareindependenteachother .Eachspanningtree
isInternalSpanningTree(IST),anditcanbecalledasMultiple
SpanningTreeInstance(MSTI).CommonSpanningTreeconnect
allMSTareasinswitchingnetwork.AMSTareacanbeconsidered
asaswitch,CSTisaspanningtreewhichisgeneratedbySTPand
RSTPprotocolcalculation.AllISTsandCSTsarecalledasCommon
andInternalSpanningTree(CIST).CISTisasinglespanningtree
toconnectallswitches.
InthisMSTPtopologystructure,anISTcanserveasasinglebridge
(switch).Inthisway,CTScanserveasanRSTPfortheinterac-
tionofcongurationinformation(BPDU).Multipleinstancescan
becreatedinanISTareaandtheseinstancesarevalidonlyin
thisarea.AninstanceisequivalenttoanRSTP ,exceptthatthe
instanceneedstoperformBPDUinteractionwithbridgesoutside
thisarea.
FIGURE49MSTPTOPOLOGICALSTRUCTURE
SpanningTreeProtocol(STP)cancalculateaccordingtothepro-
tocol.Portsaredividedintodifferentparts:
�Master:TheporttypeisintroducedinMSTPprotocol.When
themultipledifferentareasexist,themainportistheminimal
pathcostportpointtotheroot.
�Root:Theportthathastheminimalcosttorootbridgeand
takeschargeinforwardingdatatorootnode.Whenmultiple
CondentialandProprietaryInformationofZTECORPORATION95