Brocade Communications Systems ICX 7250 series, Руководство по настройке

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TABLE 23 IPv6 address types (continued)
Address type Description Address structure
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 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 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 FastIron 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.
IPv6 stateless auto-configuration
Brocade routers use the IPv6 stateless autoconfiguration 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.
The automatic configuration of a host interface works in the following way: a switch on a local link periodically sends switch
advertisement messages containing network-type information, such as the 64-bit prefix of the local link and the default route, to all
nodes on the link. When a host on the link receives the message, it takes the local link prefix from the message and appends a 64-bit
interface ID, thereby automatically configuring its interface. (The 64-bit interface ID is derived from the MAC address of the host’s NIC.)
The 128-bit IPv6 address is then subjected to duplicate address detection to ensure that the address is unique on the link.
IPv6 addressing overview
Brocade FastIron Layer 3 Routing Configuration Guide
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