Processing Ip Multicast Packets - 3Com 4007 Implementation Manual

Processing IP
Multicast Packets
Table 45 summaries how a Layer 2 Switching Module processes various
types of IGMP packets and other IP multicast packets.
Table 45 How the System Processes IP Multicast Packets
Packet Type
IGMP Membership
Reports
IGMP Queries
IGMP Leave-Group
Messages
Packets with addresses
[224 – 139].[0,128].0.x
where x = 0 – 255
Packets addressed to
known (registered) IP
multicast group
Packets addressed to
unknown IP multicast
group (group for
which no host has
registered)
* Except for the port on which the packet originated.
Some ports may not be available for carrying traffic. Two examples are:
ports that have been administratively disabled or ports that the Spanning
Tree Protocol has prevented from being in the forwarding state.

Processing IP Multicast Packets

Is Forwarded To*
Ports in the broadcast domain that lead to multicast
routers
Port that leads to the querier (if another device is the
querier)
All ports in the broadcast domain
All ports in the broadcast domain
All ports in the broadcast domain
(See "Effects of MAC Address Aliasing" later in this
chapter.)
Ports on which IGMP membership reports for that
group have been heard
Ports that lead to multicast routers
Port that leads to the querier (if another device is the
querier)
No ports, except those that lead to multicast routers
and the querier (if another device is the querier).
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