Zte ZXR10 5900E Series - Page 38

ZXR105900ESeriesCongurationGuide(IPv4Routing)
SummaryLSAsaresentoutarea,whichdescribesomeinformationofaroute,such
asthedestinationaddress,maskandcost.ANetworksummaryLSAistransmitted
toallareasexcepttheareawhichgeneratestheLSA.
lType4:ASBRsummaryLSA
TheASBRsummaryLSAisalsogeneratedbyanABR.Itdescribestheroutethat
goestotheASBRinthearea.ThecontentofASBRSummaryLSAisalmostthe
sametothatofNetworksummaryLSA.Theonlydifferenceisthatthedestination
addressdescribedbyASBRsummaryLSAisASBR(hostroute,themaskis0.0.0.0).
AASBRsummaryLSAistransmittedtoallareasexcepttheareawhichgenerates
theLSA.
lType5:ExternalLSAofAS
TheexternalLSAofASisgeneratedbyanASBR.Itmainlydescribestheinformation
ofanroutewhichgoestotheexternalAS.AnexternalLSAofAScontainssome
information,suchasdestinationaddress,maskandcostandsoon.ExternalLSAof
ASisanuniquetypethatisindependentofarea.AnexternalLSAofASistransmitted
inthewholeAS(exceptSTUBarea).
lType7:ExternalLSAofNot-So-StubbyArea(NSSA)
ExternalLSAofNSSAonlyappliestoNSSA.
lType9:Localnon-transparentLSA
lType10:Areanon-transparentLSA
OSPFoperationdependsonalltheroutersinoneareawhichshareacommonlinkstate
database.Therefore,allLSAsareoodedthroughtheareaandtheprocessingmustbe
reliable.ArouterwhichreceivesLSAsfromaspecialareawilloodtheLSAstoother
interfaceswhichbelongtotheiarea.
LSAsdonothavetheirownpackets,andtheyarecontainedinLinkstateUpdate(LSU)
packets.ALSUcancontainmanyLSAs.
WhenarouterreceivesaLSU,itabstractstheLSAfromthepacketandinputstheLSAto
itsdatabase.Meanwhile,therouterconstructsitsownLSUandsendstheupdatedLSU
toitsadjacentneighborrouter(s).
OSPFusesLinkStateAcknowledgement(LSAck)toconrmwhethereachLSAis
successfullyreceivedbyitsneighbor.ALSAckhastheheaderofanacknowledgedLSA,
whichprovidessufcientinformationforuniquelyidentifyinganLSA.
WhenaroutersendsaLSAtoaninterface,theLSAisrecordedintheretransmission
queueoftheinterface.
TherouterwillwaitthemaximumtimeintervaltoreceivetheLSAckofLSA.Iftherouter
doesnotreceivetheLSAckinthespeciedtime,itwillretransmittheLSA.
TheroutercansendtheoriginalLSUinunicastormulticastmode,buttheretransmitted
LSUismustinunicastmode.
3-6
SJ-20150114102049-003|2015-01-15(R1.0)ZTEProprietaryandCondential