TCPIP協(xié)議課件：第27章 IPv6協(xié)議

1、1第27章 IPv6協(xié)議IPv6概述IPv6地址IPv6分組ICMPv6IPv4過渡到IPv6的技術(shù)2引言：IPv4的缺陷地址空間的使用效率低地址長度：32bit層次結(jié)構(gòu)：Net id + Subnet id + Host id地址分類：A、B、C、D、E路由瓶頸地址空間的2或3層結(jié)構(gòu) 路由表的大小分組首部長度不定：不利于硬件處理每個(gè)分組獨(dú)立選路：沒有利用前后分組的相關(guān)性逐段的分片和校驗(yàn)：未能完全遵循端到端的通信原則不保證QoSBest-effort327.1 IPv6概述設(shè)計(jì)目標(biāo)繼承和取代 IPv4（RFC 791）改進(jìn)地址和路由：極大的地址空間、結(jié)構(gòu)化的路由層次首部格式：基本首部長度固定、

2、結(jié)構(gòu)化的擴(kuò)展首部網(wǎng)絡(luò)管理：一系列自動(dòng)發(fā)現(xiàn)和自動(dòng)配置技術(shù)安全性：IPsec身份驗(yàn)證（AH）和數(shù)據(jù)加密（ESP）QoS：用流標(biāo)號（flow label）取代ToS移動(dòng)性：若干利于實(shí)現(xiàn)移動(dòng)計(jì)算的技術(shù)427.2 IPv6地址（RFC 3513）FDECBA9876543210AEBFBBFF2922FFFF:1111110111101100 1111111111111111128 bits = 16 bytes = 32 hex digits十六進(jìn)制冒號表示527.2.1 十六進(jìn)制冒號表示法縮寫表示一段中開始的“ 0 ”可以忽略FDEC : BA98 : 0074 : 3210 : 000F : BB

3、FF : 0000 : FFFFFDEC : BA98 : 74 : 3210 : F : BBFF : 0 : FFFF連續(xù)幾個(gè)0段可用“ : : ”代替FDEC : 0 : 0 : 0 : F : 0 : 0 : FFFFFDEC : : F : 0 : 0 : FFFFIPv4和IPv6混合環(huán)境x : x : x : x : x : x : d . d . d . d一個(gè)地址中只能用一次“ : : ”x：十六進(jìn)制，16bitd：十進(jìn)制，8bit6地址前綴表示IPv6地址 / 前綴長度例：表示 60 bit 長的前綴 12AB00000000CD3正確12AB : : CD30 : 0 :

4、 0 : 0 : 0 / 6012AB : 0 : 0 : CD30 : : / 60錯(cuò)誤12AB : : CD30 / 6012AB : : CD3 / 60掩碼 12AB : 0 : 0 : 0 : 0 : 0 : 0 : CD30 / 60 12AB : 0 : 0 : 0 : 0 : 0 : 0 : 0CD3 / 60727.2.2 地址類型單播（Unicast）標(biāo)識一個(gè)IPv6網(wǎng)絡(luò)接口等同于IPv4的主機(jī)地址多播（Multicast）標(biāo)識一組計(jì)算機(jī)，可共享或不共享相同的前綴目的是多播地址的分組必須交付給該組中的所有成員等同于IPv4的多播地址和廣播地址任意點(diǎn)播（Anycast）標(biāo)識一

5、組計(jì)算機(jī)，具有相同的前綴目的是任意點(diǎn)播地址的分組只須交付給該組中“最近”的一個(gè)成員依據(jù)路由協(xié)議的距離度量8地址結(jié)構(gòu)和地址空間分配128 bitsFormat PrefixRest of address變長變長FPAddress type: : /128Unspecified: : 1 /128LoopbackFF00 : : /8MulticastFE80 : : /10Link-local unicastFEC0 : : /10Site-local unicastOthersGlobal unicastAnycast addresses are taken from the unicast

6、spaces927.2.3 單播地址Interface identifiersIdentify interfaces on a linkBe derived directly from the interfaces link-layer address64 bits long, Modified EUI-64 formatUnspecified address等同于 IPv4 的 0.0.0.0Loopback address等同于 IPv4 的 127.0.0.0 127.255.255.255Global unicast addressesIPv6 addresses with embed

7、ded IPv4 addressesLocal-use IPv6 unicast addresses10Global Unicast Addresses通用格式Global routing prefixn bitsSubnet IDInterface IDm bits128-n-m bitsAssign to a site（a cluster or subnets/links）An ID of a link within the siteAll global unicast addresses other than those start with binary 000 have a 64-b

8、it interface ID11IPv6 Addresses with Embedded IPv4 AddressesIPv4-compatible IPv6 addressThe hosts and routers dynamically tunnel IPv6 packets over IPv4 routing infrastructure: : d . d . d . dIPv4-mapped IPv6 addressRepresent the addresses of IPv4 nodes as IPv6 addresses: : FFFF : d . d . d . d12Loca

9、l-Use IPv6 Unicast AddressesLink-Local addressUse on a single link作用：自動(dòng)地址配置、鄰居發(fā)現(xiàn)、沒有路由器Site-Local addressUse in a single site作用：不需要全局前綴111111101010 bits0Interface ID54 bits64 bits111111101110 bitsSubnet IDInterface ID54 bits64 bits類似IPv4的私有地址路由器不轉(zhuǎn)發(fā)任何以本地地址為源或者目的的分組1327.2.4 任意點(diǎn)播地址FormatUsing any of the

10、 defined unicast address formatsUsageIdentify the set of routers belonging to an organization providing internet serviceIdentify the set of routers attached to a particular subnet，or the set of routers providing entry into a particular routing domainRestriction不能作為IPv6分組的源地址不能分配給IPv6主機(jī)，只能分配給IPv6路由器

11、Little experience1427.2.5 A Nodes Required AddressesHostLink-Local address for each interfaceAny additional Unicast and Anycast addresses that have been configured for its interfacesLoopback addressMulticast address: All-Nodes, all groups it belongs toRouterA hosts required addressesAnycast addresse

12、s it has been configuredAll-Routers Multicast addresses1527.3 IPv6 分組（RFC 2460）基本格式+16Extension Header Format17Extension HeaderHop-by-Hop OptionsRoutingFragmentDestination OptionsAuthenticationEncapsulating Security Payload18IPv4和IPv6分組首部比較取消HLEN、Checksum替代ToS字段 優(yōu)先級和流標(biāo)號字段總長度字段 有效載荷長度字段協(xié)議字段 下一個(gè)首部字段跳數(shù)

13、限制字段 TTL字段擴(kuò)展首部中實(shí)現(xiàn)分片字段（標(biāo)識/標(biāo)志/片偏移）、選項(xiàng)字段1927.4 ICMPv6Network layer in IPv6取消RARPICMP 、ARP 、IGMP ICMPv6ICMPv6差錯(cuò)報(bào)告、查詢（RFC 2463）Neighbor Discovery Protocol for IPv6，RFC 2461、3122Multicast Listener Discovery for IPv6，RFC 271020ICMPv6 Error Messages報(bào)文類型版本4版本6Destination UnreachableTime ExceededParameter Pro

14、blemSource QuenchRedirect（鄰居發(fā)現(xiàn)）Packet Too Big21ICMPv6 Information Messages報(bào)文類型版本4版本6Echo RequestEcho ReplyTimestamp RequestTimestamp ReplyInformation RequestInformation Reply22Neighbor Discovery Protocolfor IPv6FunctionMessageRouter and prefix discoveryRouter solicitationRouter advertisementAddress

15、resolution and neighbor unreachability detectionNeighbor solicitationNeighbor advertisementRedirectRedirect2327.5 從IPv4過渡到IPv6TransitionstrategiesDualstackTunnelingHeadertranslation24Dual StackIPv4TCPorUDPApplication LayerUnderlying LAN or WAN TechnologyIPv6ICMPv4IGMPARP RARPICMPv6To IPv4 systemTo IPv6 system25IPv4 NetworkTunnelingAutomatic tunnelingConfigured tunnelingIPv6HostIPv6/v4HostIPv6 headerPayloadIPv4 headerIPv6 headerPayloadIPv4 headerIPv4 NetworkIPv6HostIPv6HostIPv6 headerPayloadIPv4 headerIPv6 headerPayloadIPv4 headerIPv6 headerPayloadIPv6 headerPayloadIPv6 h