3Com SuperStack 4 Configuration Manual page 155

members in the group can change. The number of members in a permanent
multicast group can be random or even 0. Those IP multicast addresses that are
not reserved for permanent multicast groups can be used by temporary groups.
Ranges and meanings of Class D addresses are shown in
Table 174 Ranges and meaning of Class D addresses
Class D address range
224.0.0.0~224.0.0.255
224.0.1.0~238.255.255.255
239.0.0.0~239.255.255.255
Reserved multicast addresses that are commonly used are shown in
Table 175 Reserved multicast address list
Class D address
224.0.0.0
224.0.0.1
224.0.0.2
224.0.0.3
224.0.0.4
224.0.0.5
224.0.0.6
224.0.0.7
224.0.0.8
224.0.0.9
224.0.0.10
224.0.0.11
224.0.0.12
224.0.0.13
224.0.0.14
224.0.0.15
224.0.0.16
224.0.0.17
224.0.0.18
....
Ethernet Multicast MAC Addresses
When unicast IP packets are transmitted in Ethernet, the destination MAC address
is the MAC address of the receiver. However, when multicast packets are
transmitted, the destination is no longer a specific receiver but a group with
unspecific members. Therefore, the multicast MAC address should be used.
Multicast MAC addresses correspond to multicast IP addresses. IANA (Internet
IP Multicast Overview
Table 174
Meaning
Reserved multicast addresses (addresses of
permanent groups). Address 224.0.0.0 is reserved.
The other addresses can be used by routing
protocols.
Multicast addresses available for users (addresses of
temporary groups). They are valid in the entire
network.
Multicast addresses for local management. They are
valid only in the specified local range.
Meaning
Base Address (Reserved)
Addresses of all hosts
Addresses of all multicast routers
Unassigned
DVMRP routers
OSPF routers
OSPF DR (designated router)
ST routers
ST hosts
RIP-2 routers
IGRP routers
Mobile agents
DHCP server/Relay agent
All PIM routers
RSVP encapsulation
All CBT routers
Designated SBM
All SBMS
VRRP
....
167
Table 175.