Implementing Dynamic IPv6 Addresses参考.ppt

Implementing IPv6 Implementing Dynamic IPv6 Addresses Aggregatable Global Unicast Addresses Cisco uses the extended universal identifier (EUI)-64 format to do stateless autoconfiguration. This format expands the 48-bit MAC address to 64 bits by inserting “FFFE” into the middle 16 bits. To make sure that the chosen address is from a unique Ethernet MAC address, the universal/local (U/L bit) is set to 1 for global scope (0 for local scope). Link-Local Address Link-local addresses have a scope limited to the link and are dynamically created on all IPv6 interfaces by using a specific link-local prefix FE80::/10 and a 64-bit interface identifier. Link-local addresses are used for automatic address configuration, neighbor discovery, and router discovery. Link-local addresses are also used by many routing protocols. Link-local addresses can serve as a way to connect devices on the same local network without needing global addresses. When communicating with a link-local address, you must specify the outgoing interface because every interface is connected to FE80::/10. EUI-64 to IPv6 Interface Identifier A modified EUI-64 address is formed by inserting “FFFE” and “complementing” a bit identifying the uniqueness of the MAC address. EUI-64 to IPv6 Interface Identifier (Cont.) A modified EUI-64 address is formed by inserting “FFFE” and “complementing” a bit identifying the uniqueness of the MAC address. EUI-64 to IPv6 Interface Identifier (Cont.) A modified EUI-64 address is formed by inserting “FFFE” and “complementing” a bit identifying the uniqueness of the MAC address. Multicasting Examples of Permanent Multicast Addresses Anycast An IPv6 anycast address is a global unicast address that is assigned to more than one interface. Stateless Autoconfiguration A Standard Stateless Autoconfiguration A Standard Stateless Autoconfiguration (Cont.) IPv6 Mobility Summary The MAC address may form a portion of the IPv6 system ID. IPv6 multicast addresses are defined by the prefix F