Zte ZXR10 5900E Series - UDLD Configuration; UDLD Overview

Chapter11
UDLDConfiguration
TableofContents
UDLDOverview.................................................................95
ConguringUDLD..............................................................96
UDLDOverview
UDLDisalayer2logiclinkdetectionprotocol.ItcandetectEth-
ernetlinklogicconnectivityandverifyphysicalconnectivity.Dif-
ferentfromphysicalconnectiondetection,UDLDdetectsbasedon
neighbor .Thelayer1deviceistransparenttoUDLD.
UDLDdetectionbuildsupneighborrelationshipwithadjacentlayer
2devicesrstly.WhentheEthernetportwhosestatusisUPopens
UDLDfunction,thisportsendsHellopacketthatneighborhasen-
teredtoinformotheradjacentrelateddevices.Theadjacentre-
lateddevicesportthatopensUDLDfunctionreceivesthisHello
packetandsendsanEchopacketback.Fromthepointofviewof
thisdevice,thatreceivingthisEchopacketmeansthatthetwode-
vicesareinterconnectionandtheneighborrelationshipwithpeer
devicehasestablishedonthisdeviceandsendsEchopacketback.
AfterthepeerreceivingEchopacket,therelationshiponthetwo
devicesisestablished.
Afterbothsidesestablishtheneighborrelationship,senddetection
Hellopacketatregulartimetodetectifthedetectionlinkworks
normally.WhenreceivingtheHellodetectionpacketsentfrom
neighbor ,updatelocalstorageneighborbufferinformationandre-
setneighborouttime.Ifexceedneighboragingtimeandstillnot
receivingHellodetectionpacket,considerthatlinkisonabnormal
workingconditionandneeddifferentworkingmodestohandle.
UDLDhastwoworkingmodes:ordinarymodeandaggressive
mode.Inordinarymode,onlywhenpacketsarereceivedand
linkisveriedtobethroughinuni-direction,thisinterfacecanbe
down;incasecorrespondingpacketsarenotreceivedorlinkfails
tobeveriedthroughinuni-direction,thisoperationwillnotbe
conductedontheinterface;Inaggressivemode,aslongthatlink
failstobeveriedtobethroughbidirectionally,theinterfacewill
bedown.Thecommonpointofthetwomodesisthatinanycir-
cumstance,aslongasthelinkisnotveriedtoworknormally,
printalarm.
Generallyspeaking,thereareseveralconditionsthatUDLDsets
interfacedown.
CondentialandProprietaryInformationofZTECORPORATION95