IPv6 Addressing

FEC0

A site-local unicast address.

Format Prefix

A variable-length field at the beginning of the address that indicates what type of address it is—unicast, multicast, or anycast.

FE80

A link-local unicast address.

FF0E

Global multicast address.

IPv6 Addressing

IPv6 addresses are composed of eight 16-bit fields, for a total of 128 bits. The added fields and the larger address size result in an increase of 2^96 (or 4 billion times 4 billion times 4 billion) available IP addresses in the IPv6 addressing scheme. An IPv6 address is represented by hexadecimal numbers separated by colons. An example of a valid IPv6 address is FE22:00FF:002D:0000:0000:0000:3012:CCE3. Shorthand for IPv6 allows us to represent multiple fields of zeros by eliminating the extra zeros and adding a colon- FE22:00FF:002D::0:3012:CCE3. This shorthand can only be used for one group of zeros, otherwise we won't know how many groups of zeros go where. A third difference between the two types of IP addresses is that in IPv6, addresses can reflect the scope of a transmission's recipients—for example, a single node, a group, or a special kind of group- see unicast, multicast, and anycast addresses.

FF02

Link-local multicast address.

Multicast Address

Represents multiple interfaces (often on multiple devices). Multicast addresses are useful for transmitting the same data to many different devices simultaneously, as in point-to-multipoint communications. IPv6 allows for the specification of several types of multicast groups. A multicast address begins with the following hexadecimal string: FF0x, where x is a character that corresponds to a group scope ID.

Dual-Stack Approach

The ability to transmit and receive data using both IPv4 and IPv6.