Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 517)

Multi-Service IronWare Routing Configuration Guide 489
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IPv6 stateless auto-configuration
A Brocade device 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.
IPv6 stateless auto-configuration
Brocade devices use the IPv6 stateless auto-configuration feature to enable a host on a local link
to automatically configure its interfaces with new and globally unique IPv6 addresses associated
with its location. The automatic configuration of a host interface is performed without the use of a
server, such as a Dynamic Host Configuration Protocol (DHCP) server, or manual configuration.
TABLE 94 IPv6 address types
Address
type Description Address structure
Unicast An address for a single
interface. A packet sent to a
unicast address is delivered to
the interface identified by the
address. Depends on the type of the unicast address:
•
Aggregatable global address — An address equivalent to a
global or public IPv4 address. The address structure is as
follows: a fixed prefix of 2000::/3 (001), a 45-bit global routing
prefix, a 16-bit subnet ID, and a 64-bit interface ID.
•
Unique local address — An address used within a site or
intranet. For more information on ULAs, refer to RFC 4193.
•
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
Brocade device 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 as a source address only until the node has its
own address that is auto-configured.
Multicast An address for a set of
interfaces belonging to
different nodes. Sending a
packet to a multicast address
results in the delivery of the
packet to all interfaces in the
set. A multicast address has a fixed prefix of FF00::/8 (1111 1111). The
next 4 bits define the address as a permanent or temporary address.
The next 4 bits define the scope of the address (node, link, site,
organization, global).
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 router only.
An anycast address must not be used as the source address of an
IPv6 packet.