Zte ZXR10 5900E Series - RSTP Mode; MSTP Mode

ZXR105900ESeriesUserManual(EthernetSwitchingVolume)
RSTPMode
RapidSpanningTreeProtocol(RSTP)providesafasteraggregation
speedthanSTP(thatis,SSTPmode).Whenthenetworktopology
changes,thestateoftheredundantswitchportcanmakeafast
shift(Discard>Forword)inthecaseofpoint-to-pointconnection.
MSTPMode
TwoconceptsareaddedtoMultipleSpanningTreeProtocol
(MSTP):instanceandVLANmapping.SSTP/RSTPmodecanbe
regardedasaspecialcaseoftheMSTPmode.Thereonlyexists
oneinstance,thatis,instance0.TheMSTPmodealsoprovides
fastaggregationandloadbalanceundertheVLANenvironment.
InSSTPandRSTPmodes,thereisnoconceptofVLAN.Thereex-
istsoneportstate,thatis,forwardingstate.Thestateofaport
indifferentVLANsisthesame.InMSTPmodetherecanexist
multiplespanning-treeinstances.Forwardingstatesofaportun-
derdifferentVLANscanbedifferent.Manyindependentsub-tree
instancescanbeformedinsidetheMSTareatoimplementload
balance.
ThefollowingarethebasicconceptsofMSTP:
1.MSTCongID
ItisaforwardingschemeforframeswithdifferentVIDs.That
isinanMSTareaallthebridgesareforwardedtospecicspan-
ningtrees(CISToranMSTinstance)accordingtotheVIDin
theframe.
MSTCongIDiscomposedofthefollowingparts:
�Congurationname:acharacterstringof32bytes.
�Version:non-negativeintegeroftwobytes.
�Congurationsummary:signaturebasedontheMSTCon-
gT ableandafterMD5processing,withalengthof16
bytes.
MSTCongTableiscomposedof4,096continuousdual-types.
TheFirstandlastdual-bytesare0.Otherdual-byterepresents
abinarynumber .Seconddual-bytestandsfortheMSTIDto
whichVID1corresponds.Thirddual-bytestandsfortheMSTID
towhichVID2correspondsandthesecondlastdual-byterep-
resentstheMSTIDtowhichVID4094corresponds.Congura-
tionsummaryisobtainedbycalculatingtheMSTCongT able
andaxedKEYvaluethroughtheHMAC-MD5algorithm.By
resolution,itcanknowacertainVIDbelongstowhichMSTin-
stanceorCIST .
2.MSTArea
EachMSTareaiscomposedofoneorseveralconnectedbridges
withthesameMSTCongID.Thesebridgesusethesamein-
stances.ThisareaalsoincludestheLANdesignatingthebridge
intheCISTinstance.
38CondentialandProprietaryInformationofZTECORPORATION