IPv6培训内容

©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidentialBRKRST-130013745_05_2007_c21IPv6培训©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential2BRKRST-130013745_05_2007_c2WhyIPv6?©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential3BRKRST-130013745_05_2007_c2ANeedforIPv6?ƒIETFIPv6WGbeganinearly90s,tosolveaddressinggrowthissues,butCIDR,NAT,…weredevelopedƒIPv432bitaddress=4billionhosts~40%oftheIPv4addressspaceisstillunusedwhichisdifferentfromunallocatedTherisingofInternetconnecteddeviceandappliancewilleventuallydepletetheIPv4addressspaceƒIPiseverywhereData,voice,audioandvideointegrationisarealityRegionalregistriesapplyastrictallocationcontrolƒSo,onlycompellingreason:MoreIPaddresses©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential4BRKRST-130013745_05_2007_c2WhyNotNATƒItwascreatedasatempsolutionƒNATbreakstheend-to-endmodelƒGrowthofNAThassloweddowngrowthoftransparentapplicationsƒNoeasywaytomaintainstatesofNATincaseofnodefailuresƒNATbreaksecurityƒNATcomplicatesmergers,doubleNATingisneededfordevicestocommunicatewitheachother©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential5BRKRST-130013745_05_2007_c2IPv6Technology©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential6BRKRST-130013745_05_2007_c2IPv4andIPv6HeaderComparisonFragmentOffsetFlagsTotalLengthTypeofServiceIHLPaddingOptionsDestinationAddressSourceAddressHeaderChecksumProtocolTimetoLiveIdentificationVersionIPv4HeaderNextHeaderHopLimitFlowLabelTrafficClassDestinationAddressSourceAddressPayloadLengthVersionIPv6HeaderField’sNameKeptfromIPv4toIPv6FieldsNotKeptinIPv6NameandPositionChangedinIPv6NewFieldinIPv6Legend©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential7BRKRST-130013745_05_2007_c2IPv6HeaderNewField—FlowLabel(RFC3697)ƒFlowclassifiershadbeenbasedon5-tuple:Source/destinationaddress,protocoltypeandportnumbersoftransportƒSomeofthesefieldsmaybeunavailableduetofragmentation,encryptionorlocatingthempastextensionheadersƒWithflowlabel,eachsourcechoosesitsownflowlabelvalues;routersusesourceaddr+flowlabeltoidentifydistinctflowsƒFlowlabelvalueof0usedwhennospecialQoSrequested(thecommoncasetoday)IPv6HeaderNextHeaderHopLimitFlowLabelTrafficClassDestinationAddressSourceAddressPayloadLengthVersion20-BitFlowLabelFieldtoIdentifySpecificFlowsNeedingSpecialQoS©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential8BRKRST-130013745_05_2007_c2ExtensionHeadersIPv6BaseHeader(40octets)0ormoreExtensionHeadersIPv6PacketNextHeader=17ExtHdrLengthExtHdrDataDataBaseheaderNextHeader=01stExtensionHeaderNextHeader=43LastExtensionHeaderNextHeader=17…©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential9BRKRST-130013745_05_2007_c2MTUIssuesƒMinimumlinkMTUforIPv6is1280octets(vs.68octetsforIPv4)=onlinkswithMTU1280,link-specificfragmentationandreassemblymustbeusedƒImplementationsareexpectedtoperformpathMTUdiscoverytosendpacketsbiggerthan1280ƒMinimalimplementationcanomitPMTUdiscoveryaslongasallpacketskept≤1280octetsƒAhop-by-hopoptionsupportstransmissionof“jumbograms”withupto2^32octetsofpayload;payloadisnormally2^16©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential10BRKRST-130013745_05_2007_c2IPv6Addressing©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential11BRKRST-130013745_05_2007_c2IPv6Addressing©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential12BRKRST-130013745_05_2007_c2AddressingFormatƒ16-bithexadecimalnumbersƒNumbersareseparatedby(:)ƒHexnumbersarenotcasesensitiveƒAbbreviationsarepossibleLeadingzerosincontiguousblockcouldberepresentedby(::)Example:2001:0db8:0000:130F:0000:0000:087C:140B2001:0db8:0:130F::87C:140BDoublecolononlyappearsonceintheaddressRepresentation©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential13BRKRST-130013745_05_2007_c2AddressingƒRepresentationofprefixisjustlikeCIDRƒInthisrepresentationyouattachtheprefixlengthƒLikev4address:198.10.0.0/16ƒV6addressisrepresentedthesameway:2001:db8:12::/48ƒOnlyleadingzerosareomitted.Trailingzerosarenotomitted2001:0db8:0012::/48=2001:db8:12::/482001:db8:1200::/48≠2001:db8:12::/48PrefixRepresentation©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential14BRKRST-130013745_05_2007_c2IPv6—AddressingModelƒAddressesareassignedtointerfacesChangefromIPv4mode:ƒInterface“expected”tohavemultipleaddressesƒAddresseshavescopeLinkLocalUniqueLocalGlobalƒAddresseshavelifetimeValidandpreferredlifetimeLinkLocalUniqueLocalGlobal©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential15BRKRST-130013745_05_2007_c2TypesofIPv6AddressesƒUnicastAddressofasingleinterface.One-to-onedeliverytosingleinterfaceƒMulticastAddressofasetofinterfaces.One-to-manydeliverytoallinterfacesinthesetƒAnycastAddressofasetofinterfaces.One-to-one-of-manydeliverytoasingleinterfaceinthesetthatisclosestƒNomorebroadcastaddresses©2007CiscoSystems,Inc.Allrightsreserved.CiscoConfidential16BRKRST-130013745_05_2007_c2AggregatableGlobalUnicastAddressesAggregatableGlobalUnicastAddressesAre:ƒAddressesforgenericuseofIPv6ƒStructuredasahierarchytokeeptheaggregation00164Bits345Bits16BitsProviderSiteHostGlobalRoutingPrefixSLAInter