3Com 7750 Series Command Reference Manual page 528

3Com Switch 7750 Series
Command Reference Guide – Multicast
filtering ACL configured on the access port to determine if the port can join the
corresponding multicast group or not. If yes, it adds the port to the forward port list of
the multicast group. If not, it drops the IGMP host report message and does not forward
the corresponding data stream to the port. In this way, you can control the multicast
streams that users can access.
An ACL rule defines a multicast address or a multicast address range (for example
224.0.0.1 to 239.255.255.255) and is used to.
Allow the port(s) to join only the multicast group(s) defined in the rule by a permit
statement.
Inhibit the port(s) from joining the multicast group(s) defined in the rule by a deny
statement.
Note:
One port can belong to multiple VLANs. But for each VLAN on the port, you can
configure only one ACL.
If the port does not belong to the specified VLAN, the filter ACL you configured does
not take effect on the port.
If no ACL rule is configured in the command, the system will reject the multicast
packets from all the multicast groups.
Since most devices broadcast unknown multicast packets, this function is often
used together with the unknown multicast packet drop function to prevent multicast
streams from being broadcasted to a filtered port as unknown multicast.
Example
# Configure ACL 2000 to allow users under port Ethernet 1/0/1 to access the multicast
streams in groups 225.0.0.0 to 225.255.255.255.
Configure ACL 2000.
<3Com> system-view
System View: return to User View with Ctrl+Z.
[3Com] acl number 2000
[3Com-acl-basic-2000] rule permit source 225.0.0.0 0.255.255.255
[3Com-acl-basic-2000] quit
Create VLAN 2 and add Ethernet 1/0/1 port to VLAN 2.
[3Com] vlan 2
[3Com-vlan2] port Ethernet 1/0/1
Gigabit[3Com-vlan2] quit
Configure ACL 2000 on Ethernet 1/0/1 to allow this VLAN 2 port to join only the
IGMP multicast groups defined in the rule of ACL 2000.
[3Com] interface Ethernet 1/0/1
Chapter 1 IGMP Snooping Configuration Commands
1-8