Zte ZXR10 5900E Series - Figure 3-1 OSPF Router Type

ZXR105900ESeriesCongurationGuide(IPv4Routing)
RouterPriorityandDRElection
Everyinterfacehasitsownpriorityonrouter,whichaffectsthecapabilityoftherouterto
becomeaDRorBDRonthenetwork.Thepriorityofrouterinterfaceisexpressedbyan
eight-bitunsignedinteger,rangingfrom0to255(thedefaultvalueis"1").
InDRelection,theinterfaceprioritiesarecomparedatrst.Therouterwiththehighest
prioritybecomesaDRinthenetworksegment.Iftheprioritiesoftworoutersarethesame,
therouterwhichrouteridisthelargestwillbecomeaDR.Therouterwhichpriorityis0
cannotbeaDRorBDR.
DRisaconceptusedinnetworksegment,whichisbasedonrouterinterface.Thatis,
aroutercanbeaDRonitsaninterface,anditcanbeBDRorDROtheronitsanother
interface.
OSPFArea
Toreducetheinformationsizethateachrouterstoresandmaintainsandshieldtherange
thatnetworkchanginginuenceson,OSPFdividesanetworkintosomeminorparts.
Eachroutermusthavethecompleteinformationoftheareawhereitlocates.Area
BorderRouter(ABR)isusedtotransmitroutinginformationbetweendifferentareas.The
informationissharedbyareas.Theroutinginformationcanbelteredonareaedge,
whichreducestheroutinginformationstoredinrouters.
Anareaisidentiedwith32-bitunsignednumber.Area0isreservedtoidentifybackbone
network,andallotherareasmustbeconnectedtoarea0.ThebackboneareaofOSPF
networkhastobecontinuous.Routerscanbeoneormultipleofthefollowingtypes
accordingtoitstasksinthearea,asshowninFigure3-1.
Figure3-1OSPFRouterType
lInternalrouter
AllinterfacesoftherouterbelongtothesameOSPFarea.Aninternalrouteronly
generatesaRouterLSAandsavesaLink-stateDatabase(LSDB).
3-4
SJ-20150114102049-003|2015-01-15(R1.0)ZTEProprietaryandCondential