Chapter9
IPv6Tunnel
Configuration
TableofContents
IPv6TunnelOverview.........................................................65
ConguringIPv6Tunnel.....................................................68
ConguringIPv6TunnelMaintenanceandDiagnosis...............69
IPv6TunnelCongurationExample......................................69
IPv6TunnelOverview
ItisimpossiblethatIPv6replacesIPv4totallyandimmediately.
Therefore,theyexistsimultaneouslyinthesameenvironmentfor
quitealongtime.Agoodtransitionmechanismisneededtopro-
videastabletransitionandminimizetheeffectsontheexisting
users.
Atpresent,thistopicisthemaintargetofIETFngtransworkgroup.
Manytransitionmechanismshavebeenputforwardandsomeof
themhavebeenusedfor6Bone.IETFrecommendssometransi-
tionmechanisms,suchastunneltechnology,DualStackandNet-
workAddressTranslation(NAT)technology.
IPv6TunnelTechnology
Tunneltechnologyistheprimarywayforcommunicationsbetween
IPv6singlesubnetsduringthetransitionperiod.Thismechanism
connectstheisolatedIPv6nodeislandsovertheIPv4networksea.
Atthesametime,ifIPv6becomesdominantinthefuture,itwill
serverasconnectionsamongtheIPv4islands.
Thecoreconceptofthetunneltechnologyistomaketheexisting
IPv4networkbecomethecarrierforestablishmentoftheIPv6
communicationsbyencapsulatingtheIPv6datagramintotheIPv4
datagram.Thedatagramtransmissionbetweennodesatthetwo
endsofatunnelisimplementedthroughtheIPv4mechanism,
wherethetunnelistreatedasadirectlyconnectedchannel.
Inshort,theideaofthetunnelpolicyistoencapsulatetheIPv6
datagramintotheIPv4byarouter .Theprotocoleldofthe
IPv4datagramheaderissetas41,whichindicatsthenetload
ofthissub-groupisanIPv6sub-group.Thesourceaddressand
CondentialandProprietaryInformationofZTECORPORATION65