H3C Technologies H3C S10500 Series Switches - Manual (Page 114)

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• Link-local addresses are used for communication among link-local nodes for neighbor discovery
and stateless autoconfiguration. Packets with link-local source or destination addresses are not
forwarded to other links.
• Site-local unicast addresses are similar to private IPv4 addresses. Packets with site-local source or
destination addresses are not forwarded out of the local site (or a private network).
• A loopback address is 0:0:0:0:0:0:0:1 (or ::1). It cannot be assigned to any physical interface and
can be used by a node to send an IPv6 packet to itself in the same way as the loopback address
in IPv4.
• An unspecified address is 0:0:0:0:0:0:0:0 (or ::). It cannot be assigned to any node. Before
acquiring a valid IPv6 address, a node fills this address in the source address field of IPv6 packets.
The unspecified address cannot be used as a destination IPv6 address.
Multicast addresses
IPv6 multicast addresses listed in Table 8 are reserved for special purposes.
Table 8 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
Multicast addresses also include solicited-node addresses. A node uses a solicited-node multicast
address to acquire the link-layer address of a neighboring node on the same link and to detect duplicate
addresses. Each IPv6 unicast or anycast address has a corresponding solicited-node address. The format
of a solicited-node multicast address is:
FF02:0:0:0:0:1:FFXX:XXXX
Where FF02:0:0:0:0:1:FF is fixed and consists of 104 bits, and XX:XXXX is the last 24 bits of an IPv6
unicast address or anycast address.
EUI-64 address-based interface identifiers
An interface identifier is 64 bits and uniquely identifies an interface on a link.
Interfaces generate EUI-64 address-based interface identifiers differently.
• On an IEEE 802 interface (such as a VLAN interface)
The interface identifier is derived from the link-layer address (typically a MAC address) of the interface.
The MAC address is 48 bits long. To obtain an EUI-64 address-based interface identifier, you must insert
the hexadecimal number FFFE (16 bits of 1111111111111110) into the MAC address (behind the 24th
high-order bit), and set the universal/local (U/L) bit (which is the seventh high-order bit) to 1, ensuring
that the obtained EUI-64 address-based interface identifier is globally unique.
Figure 45 shows how an EUI-64 address-based interface identifier is generated from a MAC address.