6
Address block
Description
224.0.1.0 to 238.255.255.255
Globally scoped group addresses. This block includes the
following types of designated group addresses:
•
232.0.0.0/8
—SSM group addresses.
•
233.0.0.0/8
—Glop group addresses.
239.0.0.0 to 239.255.255.255
Administratively scoped multicast addresses. These addresses
are considered locally unique rather than globally unique. You can
reuse them in domains administered by different organizations
without causing conflicts. For more information, see RFC 2365.
NOTE:
Glop is a mechanism for assigning multicast addresses between different ASs. By filling an AS
number into the middle two bytes of 233.0.0.0, you get 255 multicast addresses for that AS. For more
information, see RFC 2770.
Table 3 Common permanent multicast group addresses
Address
Description
224.0.0.1
All systems on this subnet, including hosts and routers.
224.0.0.2
All multicast routers on this subnet.
224.0.0.3
Unassigned.
224.0.0.4
DVMRP routers.
224.0.0.5
OSPF routers.
224.0.0.6
OSPF designated routers and backup designated routers.
224.0.0.7
Shared Tree (ST) routers.
224.0.0.8
ST hosts.
224.0.0.9
RIPv2 routers.
224.0.0.11
Mobile agents.
224.0.0.12
DHCP server/relay agent.
224.0.0.13
All Protocol Independent Multicast (PIM) routers.
224.0.0.14
RSVP encapsulation.
224.0.0.15
All Core-Based Tree (CBT) routers.
224.0.0.16
Designated SBM.
224.0.0.17
All SBMs.
224.0.0.18
VRRP.
•
IPv6 multicast addresses:
Figure 4 IPv6 multicast format
Group ID (112 bits)
0xFF
Flags
Scope
0
7
11
15
31