3Com Switch 4210 9-Port, Configuration Manual

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528 C
HAPTER
46: IP
V
6 M
ANGEMENT
C
ONFIGURATION
Unicast address
There are several forms of unicast address assignment in IPv6, including global
unicast address, link-local address, and site-local address.
■
The global unicast address, equivalent to an IPv4 public address, is used for
aggregatable links and provided for network service providers. This type of
address allows efficient routing aggregation to restrict the number of global
routing entries.
■
The link-local address is used for the neighbor discovery protocol as well as
communication between link-local nodes in stateless autoconfiguration.
Routers must not forward any packets with link-local source or destination
addresses to other links.
■
IPv6 unicast site-local addresses are similar to private IPv4 addresses. Routers
must not forward any packets with site-local source or destination addresses
outside of the site (equivalent to a private network).
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Loopback address: The unicast address 0:0:0:0:0:0:0:1 (represented in shorter
format as ::1) is called the loopback address and may never be assigned to any
physical interface. Like the loopback address in IPv4, it may be used by a node
to send an IPv6 packet to itself.
■
Unassigned address: The unicast address :: is called the unassigned address and
may not be assigned to any node. Before acquiring a valid IPv6 address, a node
may fill this address in the source address field of an IPv6 packet, but may not
use it as a destination IPv6 address.
Multicast address
Multicast addresses listed in Table 384 are reserved for special purpose.
Besides, there is another type of multicast address: solicited-node address. The
solicited-node multicast address is used to acquire the link-layer addresses of
neighbor nodes on the same link and is also used for duplicate address detection.
Each IPv6 unicast or anycast address has one corresponding solicited-node
address. The format of a solicited-node multicast address is as follows:
FF02:0:0:0:0:1:FFXX:XXXX
Anycast address Anycast addresses are taken from unicast address space
and are not syntactically distinguishable from unicast
addresses.
Table 384 Reserved IPv6 multicast addresses
Address Application
FF01::1 Node-local scope all-nodes multicast address
FF02::1 Link-local scope all-nodes multicast address
FF01::2 Node-local scope all-routers multicast address
FF02::2 Link-local scope all-routers multicast address
FF05::2 Site-local scope all-routers multicast address
Table 383 Mapping between address types and format prefixes
Type Format prefix (binary) IPv6 prefix ID