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1、IP Version 6IP Version 61SCUT DT the value is 6.Priority (4 bits): Priority value of each packet specifies the traffic class. Values between 0 and 7 are defined for congestion controlled traffic (data) and between 8 and 15 for non-congestion controlled traffic (video and audio).13SCUT DTIdentificati
2、on, Fragmentation Flags and Fragment Offset. Higher-level protocols tend to avoid the fragmentation and an extension can be employed if Fragmentation is needed.Header Checksum. IPv6s optional authentication header that can also be used to ensure integrity.18SCUT DTPadN: N X00 bytes used for padding,
3、 N is given in the field of the length byte. The padding is used to retain 8-byte alignment for subsequent headers to make processing header more efficient.4. IPv6 Extension Header4. IPv6 Extension Header23SCUT DTM = 1: not the last fragment.Fragment Identification: an unambiguous identifier used to
4、 identify fragments of the same datagram.Keep same value for a divided packet.4. IPv6 Extension Header4. IPv6 Extension Header32SCUT DT Each group of 16 bits is written in hexadecimal with a colon separating groups; For example:69DC:8864:FFFF:FFFF:0:1280:8C0A:FFFF36SCUT DTThe address corresponds to
5、a single computer;Special- purpose unicast addresses:Loopback address ( :1 ); It is assigned to a virtual interface over which a host can send packets only to itself; (IPv4: 127.0.0.1)Unspecified address ( : ); It is used as a source address by a host while performing autoconfiguration; (IPv4: 0.0.0
6、.0) 5. IPv6 Addressing5. IPv6 Addressing39SCUT DT 0 8 16 127FPFlagsGroup IDScopeFP Format Prefix: 1111 1111.Flags: (only the low-order bit being defined)0000: Permanent address assigned by a numbering authority. 0001: Transient address.5. IPv6 Addressing5. IPv6 Addressing44SCUT DTFF02:1 All nodes li
7、nk-local (Defines all systems on the local network); FF01:2 All routers node-local (Defines all routers local to the host itself);FF02:2 All routers link-local (Defines all routers on the same link as the host);FF05:2 All routers site-local (Defines all routers on the same site as the host); 5. IPv6
8、 Addressing5. IPv6 Addressing46SCUT DTFF02:1:2 All DHLC agents link-local;FF05:1:3 All HDLC servers site-local;Note: The flags of all above special-purpose multicast address are 0000 (defined by the numbering authority);The function scope of the multicasting is determined by the scope field of the a
9、ddress; 5. IPv6 Addressing5. IPv6 Addressing47SCUT DT* xx:xxxx - the last 24 bits of a nodes unicast address5. IPv6 Addressing5. IPv6 Addressing48SCUT DTP Prefix length (0128)Domain Name The domain name of the prefix The IPv6 addressing system has been designed to allow for multiple addresses on a s
10、ingle interface and to facilitate address renumbering.90SCUT DT(b) The client uses multicast addresses to contact the server, rather than broadcasts.(c) DHCPv6 can provide more than one address when requested.(d) Some DHCP options, which are now unnecessary, can be obtained by using IPv6 neighbor di
11、scovery.(e) There is no requirement for BOOTP compatibility.(f) There is a new reconfiguration messages. Clients must listen for reconfiguration messages once they have received their initial configuration.96SCUT DT&P LabsSCUT DT&P LabsDHCP in IPv6 2. 2. DHCPv6 MessagesDHCPv6 Messages(a) DHCP Solici
12、t (multicast message): The DHCP client forwards the message to FF02:1:2, the well-known multicast address for all DHCP agents/servers. The relay agent forward the message to FF05:1:3, the well-known address for all DHCP servers.(b) DHCP Advertise (unicast message): be sent by a DHCP server in respon
13、se to a DHCP Solicit to the soliciting client or the relay agent.(c) DHCP Request (unicast message): be sent by a DHCP client to the DHCP server allocated/relay agent for requesting an address and/or configuration parameters.(d) DHCP Reply (unicast message): be sent by a DHCP server in response to a
14、 DHCP Request.(e) DHCP Release (unicast message): be sent by a DHCP client to the server, informing it of resource that are being released.(f) DHCP Reconfigure (unicast or multicast message ): be sent by the server to one more clients , to informing them that there is new configuration information a
15、vailable.97SCUT DT&P LabsSCUT DT&P LabsInternet Transition:Internet Transition: Migrating from IPv4 to IPv6Migrating from IPv4 to IPv698SCUT DT&P LabsSCUT DT&P LabsMigrating from IPv4 to IPv6 1. The Transition TechniquesThe Transition TechniquesDual-stack IP implementations: for hosts and routers th
16、at can/must interoperate between IPv4 and IPv6.Embedding of IPv4 addresses in IPv6 addresses: IPv6 hosts will be assigned addresses that are interoperable with IPv4, and IPv4 host addresses will be mapped to IPv6.IPv6-over-IPv4 tunneling mechanisms: for carrying IPv6 packets across IPv4 router networks.IPv4/IPv6 header translation: it is intended for use when implementation of IPv6 is well advanced and only a few IPv4-only s
