Brocade Communications Systems 6650 manual IPv6 addressing overview IPv6 address types

		IPv6 addressing overview	5
TABLE 22	IPv6 address types
.
Address	Description	Address structure
type
Unicast	An address for a single	Depends on the type of the unicast address:
	interface. A packet sent to a	• Aggregatable global address—An address equivalent to a global
	unicast address is delivered to	or public IPv4 address. The address structure is as follows: a
	the interface identified by the	fixed prefix of 2000::/3 (001), a 45-bit global routing prefix, a
	address.	16-bit subnet ID, and a 64-bit interface ID.

•Site-local address—An address used within a site or intranet. (This address is similar to a private IPv4 address.) A site consists of multiple network links. The address structure is as follows: a fixed prefix of FEC0::/10 (1111 1110 11), a 16-bit subnet ID, and a 64-bit interface ID.

•Link-local address—An address used between directly connected nodes on a single network link. The address structure is as follows: a fixed prefix of FE80::/10 (1111 1110 10) and a 64-bit interface ID.

•IPv4-compatible address—An address used in IPv6 transition mechanisms that tunnel IPv6 packets dynamically over IPv4 infrastructures. The address embeds an IPv4 address in the low-order 32 bits and the high-order 96 bits are zeros. The address structure is as follows: 0:0:0:0:0:0:A.B.C.D.

•Loopback address—An address (0:0:0:0:0:0:0:1 or ::1) that a switch can use to send an IPv6 packet to itself. You cannot assign a loopback address to a physical interface.

•Unspecified address—An address (0:0:0:0:0:0:0:0 or ::) that a node can use until you configure an IPv6 address for it.

Multicast An address for a set of	A multicast address has a fixed prefix of FF00::/8 (1111 1111). The
interfaces belonging to	next 4 bits define the address as a permanent or temporary
different nodes. Sending a	address. The next 4 bits define the scope of the address (node, link,
packet to a multicast address	site, organization, global).
results in the delivery of the
packet to all interfaces in the
set.

Anycast	An address for a set of
	interfaces belonging to
	different nodes. Sending a
	packet to an anycast address
	results in the delivery of the
	packet to the closest interface
	identified by the address.

An anycast address looks similar to a unicast address, because it is allocated from the unicast address space. If you assign a unicast address to multiple interfaces, it is an anycast address. An interface assigned an anycast address must be configured to recognize the address as an anycast address.

An anycast address can be assigned to a switch only.

An anycast address must not be used as the source address of an IPv6 packet.

A switch automatically configures a link-local unicast address for an interface by using the prefix of FE80::/10 (1111 1110 10) and a 64-bit interface ID. The 128-bit IPv6 address is then subjected to duplicate address detection to ensure that the address is unique on the link. If desired, you can override this automatically configured address by explicitly configuring an address.

NOTE

Brocade ICX 6650 devices support RFC 2526, which requires that within each subnet, the highest 128 interface identifier values reserved for assignment as subnet anycast addresses. Thus, if you assign individual IPv6 addresses within a subnet, the second highest IPv6 address in the subnet does not work.

Brocade ICX 6650 Administration Guide	103
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