Zte ZXR10 T600

ZXR10T600/T1200UserManual(IPv6Volume)
destinationaddressoftheIPv4datagramcorrespondtotheIPv4
addressesofthetunnelingressandegressrespectively.Atthe
egressofthetunnel,extracttheIPv6datagramandthenforward
ittothedestinationsite.
Tunneltechnologyonlyrequiresmodicationtotheingressand
egressofthetunnelandhasnorequirementstotheotherparts;
itiseasytoberealized.
Theadvantageoftunneltechnologyhighlightstransparencyofthe
tunnel.ItenablescommunicationsbetweenIPv6hosts,ignoring
theexistingtunnel,wherethetunnelonlyserversasaphysical
channel.Tunneltechnologyiswidelyusedduringtheearlystage
whenIPv4evolvestoIPv6.However ,itcannotrealizecommuni-
cationsbetweenIPv4hostsandIPv6hosts.
Atunnelhasaningresspointandadestinationpoint.T omakethe
datagothroughatunnel,theaddressesofitstwoendsmustbe
known.Theingresspointcanbedetermineddirectly,becauseit
appearsontheboundaryoftheIPv4basicstructure.However ,it
ismorecomplicatedtodeterminethedestinationpointofatunnel.
Tunnelsareclassiedasconguredtunnelandauto-congured
tunnelbasedonthedifferentwaystoobtainthedestinationad-
dressofatunnel.Auto-congurationtunnelsaremainlyusedin
router-to-router ,whileauto—conguredtunnelsconsistofthefol-
lowingthreemodes:
�6in4tunnel
�4in6tunnel
�6to4tunnel
The6to4technologyusesspecialIPv6addressestoenableIPv6
islandsintheIPv4seatoconnecttoeachother .Then,theIPv6
egressroutercreatestunnelconnectionwithotherIPv6elds.The
endpointofanIPv4tunnelcanbeautomaticallyextractedfrom
theaddressprexofanIPv6eld,becausetheIPv4addressofa
siteiscontainedintheIPv6addressprex.
Theotherinterestingfeatureofthe6to4technologyisthatitcan
automaticallyextractanIPv4addressfromanIPv6addressprex.
Withthismechanism,asitecanconguretheIPv6withoutapply-
ingtotheregistrationinstitutionfortheIPv6addressspace.It
simpliesthemanagementoftheISPprovidersatthesametime.
Itcanbeimaginedthatinanenterprisewithmanydepartments,
eachdepartmentcanbuildavirtualIPv6externalnetworkbyusing
privateaddressesandtheNATtechnologywithinthedepartment
throughthe6to4policy.Itcanalsore-establishthepoint-to-point
IPconnection,andallowtheserverslocatingondifferentplaces
ofanenterprisetousetheIPsecprotocol,thusfurtherimproving
thenetworksecurity.
Inaddition,6to4mechanismallowscommunicationsbetween
6to4-basedIPv6sitesandpureIPv6sitesthroughthe6to4Relay
Router .Then,thetwoendpointsthatarecommunicatingwith
eachotherrequirenoavailableIPv4connection.The6to4Relay
RouterisrecommendedtorunBGPforwiderapplication.
Whenthefollowingtwoconditionsarefullled,encapsulateIPv6
packetsintoIPv4packetsbytheType41IPv4protocol,asdened
bytheconversionmechanismRFC.Oneconditionisthe6to4router
oftherequestingsitesendspacketstoanothersitethatresides
66CondentialandProprietaryInformationofZTECORPORATION