Managing HP Serviceguard for Linux Ninth Edition, April 2009

SLA ID = Site-Level Aggregation Identifier.
Interface ID = Interface Identifier.
Link-Local Addresses
Link-local addresses have the following format:
Table D-6
64 bits54 bits10 bits
interface ID01111111010
Link-local address are supposed to be used for addressing nodes on a single link.
Packets originating from or destined to a link-local address will not be forwarded by
a router.
Site-Local Addresses
Site-local addresses have the following format:
Table D-7
64 bits16 bits38 bits10 bits
interface IDsubnet ID01111111011
Link-local address are supposed to be used within a site. Routers will not forward any
packet with site-local source or destination address outside the site.
Multicast Addresses
A multicast address is an identifier for a group of nodes. Multicast addresses have the
following format:
Table D-8
112 bits4 bits4 bits8 bits
group IDscopflags11111111
“FF” at the beginning of the address identifies the address as a multicast address.
The “flags” field is a set of 4 flags “000T”. The higher order 3 bits are reserved and
must be zero. The last bit ‘T’ indicates whether it is permanently assigned or not. A
value of zero indicates that it is permanently assigned otherwise it is a temporary
assignment.
The “scop” field is a 4-bit field which is used to limit the scope of the multicast group.
For example, a value of ‘1’ indicates that it is a node-local multicast group. A value of
‘2’ indicates that the scope is link-local. A value of “5” indicates that the scope is
site-local.
320 IPv6 Network Support