3Com Switch 7750 Configuration Guide

418 CHAPTER 41: MULTICAST OVERVIEW
■ A multicast group whose addresses are assigned by IANA is a permanent
multicast group. It is also called reserved multicast group.
Note that:
■ The IP addresses of a permanent multicast group keep unchanged, while the
members of the group can be changed.
■ There can be any number of, or even zero, members in a permanent multicast
group.
■ Those IP multicast addresses not assigned to permanent multicast groups can
be used by temporary multicast groups.
Class D IP addresses range from 224.0.0.0 to 239.255.255.255. For details, see
Table 328.
As specified by IANA, the IP addresses ranging from 224.0.0.0 to 224.0.0.255 are
reserved for network protocols on local networks. The following table lists
commonly used reserved IP multicast addresses:
Table 328 Range and description of Class D IP addresses
Class D address range Description
224.0.0.0 to 224.0.0.255 Reserved multicast addresses (IP addresses for
permanent multicast groups). The IP address 224.0.0.0 is
reserved. Other IP addresses can be used by routing
protocols.
224.0.1.0 to 231.255.255.255
233.0.0.0 to 238.255.255.255
Available any-source multicast (ASM) multicast addresses
(IP addresses of temporary groups). They are valid for the
entire network.
232.0.0.0 to 232.255.255.255 Available source-specific multicast (SSM) multicast group
addresses.
239.0.0.0 to 239.255.255.255 Local management multicast addresses, which are used
in the local use only.
Table 329 Reserved IP multicast addresses
Class D address range Description
224.0.0.1 Address of all hosts
224.0.0.2 Address of all multicast routers
224.0.0.3 Unassigned
224.0.0.4 Distance vector multicast routing protocol (DVMRP) routers
224.0.0.5 Open shortest path first (OSPF) routers
224.0.0.6 Open shortest path first designated routers (OSPF DR)
224.0.0.7 Shared tree routers
224.0.0.8 Shared tree hosts
224.0.0.9 RIP-2 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 Resource reservation protocol (RSVP) encapsulation
224.0.0.15 All core-based tree (CBT) routers