3Com 4210 PWR - Page 205

IGMP Snooping Configuration 203
Configuring a Multicast
Group Filter
On an IGMP Snooping-enabled switch, the configuration of a multicast group
allows the service provider to define restrictions on multicast programs available to
different users.
In an actual application, when a user requests a multicast program, the user's host
initiates an IGMP report. Upon receiving this report message, the switch checks
the report against the ACL rule configured on the receiving port. If the receiving
port can join this multicast group, the switch adds this port to the IGMP Snooping
multicast group list; otherwise the switch drops this report message. Any multicast
data that has failed the ACL check will not be sent to this port. In this way, the
service provider can control the VOD programs provided for multicast users.
Make sure that an ACL rule has been configured before configuring this feature.
Configuring a multicast group filter in system view
Configuring a multicast group filter in Ethernet port view
n
■ A port can belong to multiple VLANs, you can configure only one ACL rule per
VLAN on a port.
■ If no ACL rule is configured, all the multicast groups will be filtered.
■ Since most devices broadcast unknown multicast packets by default, this
function is often used together with the function of dropping unknown
multicast packets to prevent multicast streams from being broadcast as
unknown multicast packets to a port blocked by this function.
■ The configuration performed in system view takes effect on all ports of the
switch if no VLAN is specified; if one or more VLANs are specified, the
configuration takes effect on all ports in the specified VLAN(s).
■ The configuration performed in Ethernet port view takes effect on the port no
matter which VLAN it belongs to if no VLAN is specified; if one or more VLANs
are specified, the configuration takes effect on the port only if the port belongs
to the specified VLAN(s).
Tab le 151 Configure a multicast group filter in system view
Operation Command Remarks
Enter system view system-view -
Configure a multicast
group filter
igmp-snooping
group-policy acl-number [
vlan vlan-list ]
Required
No group filter is configured by default,
namely hosts can join any multicast
group.
Tab le 152 Configure a multicast group filter in Ethernet port view
Operation Command Remarks
Enter system view system-view -
Enter Ethernet port
view
interface interface-type
interface-number
-
Configure a multicast
group filter
igmp-snooping
group-policy acl-number [
vlan vlan-list ]
Optional
No group filter is configured by default,
namely hosts can join any multicast
group.