7
Address Description
224.0.0.16
Designated Subnetwork Bandwidth Management (SBM)
224.0.0.17 All
SBMs
224.0.0.18 Virtual
Router
Redundancy Protocol (VRRP)
2.
IPv6 multicast addresses
Figure 4 IPv6 multicast format
The following describes the meanings of the fields of an IPv6 multicast address:
•
0xFF—The most significant eight bits are 11111111, which indicates that this address is an IPv6
multicast address.
•
Flags—The Flags field contains four bits.
Figure 5 Format of the Flags field
Table 4 Description on the bits of the Flags field
Bit Description
0
Reserved, set to 0
R
•
When set to 0, it indicates that this address is an IPv6 multicast address without an
embedded RP address.
•
When set to 1, it indicates that this address is an IPv6 multicast address with an
embedded RP address—the P and T bits must also be set to 1.
P
•
When set to 0, it indicates that this address is an IPv6 multicast address not based on
a unicast prefix.
•
When set to 1, it indicates that this address is an IPv6 multicast address based on a
unicast prefix—the T bit must also be set to 1.
T
•
When set to 0, it indicates that this address is an IPv6 multicast address
permanently-assigned by IANA.
•
When set to 1, it indicates that this address is a transient, or dynamically assigned
IPv6 multicast address.
•
Scope—The Scope field contains four bits, which indicate that the scope of the IPv6
internetwork for which the multicast traffic is intended.
Table 5 Values of the Scope field
Value Meaning
0, F
Reserved
1 Interface-local
scope
2 Link-local
scope
3 Subnet-local
scope