3Com 7757 Configuration Manual page 433

Configuring IGMP
Snooping Filtering ACLs
If the IGMP fast leave feature is enabled, when receiving an IGMP Leave message,
the switch immediately removes the port from the multicast group. When a port
has only one user, enabling the IGMP fast leave feature on the port can save
bandwidth.
Enabling the IGMP fast leave feature for all ports globally
Table 340 Enable the IGMP fast leave feature for all ports globally
Operation
Enter system view
Enable the fast leave feature
from the multicast group of
the specific VLAN for all port
Enabling the fast leave feature for a port
Table 341 Enable the fast leave feature for a port
Operation
Enter system view
Enter Ethernet port view
Enable the fast leave feature
from the multicast group of
the specific VLAN for a port
You can configure multicast filtering ACLs on the switch ports connected to user
ends so as to use the IGMP Snooping filter function to limit the multicast streams
that the users can access. With this function, you can treat different VoD users in
different ways by allowing them to access the multicast streams in different
multicast groups.
In practice, when a user orders a multicast program, an IGMP report message is
generated. When the message arrives at the switch, the switch examines the
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 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.
Make sure that ACL rules have been configured before configuring this feature.
Configuring IGMP Snooping filtering ACLs globally
Table 342 Configure IGMP Snooping filtering ACLs globally
Operation Command
Enter system view system-view
IGMP Snooping Configuration
Command
system-view
igmp-snooping fast-leave
[ vlan vlan-list ]
Command
system-view
interface interface-type
interface-number
igmp-snooping fast-leave
[ vlan vlan-list ]
Description
-
433
Description
-
Optional
By default, the fast leave
feature from a multicast
group for all ports is disabled.
Description
-
-
Optional
By default, the fast leave
feature from a multicast
group for a port is disabled.