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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 17 Co nfiguring IGMP S noo ping and M VR
Configuring IGMP Filtering
This is an example of output fro m the show mvr interface privileged EXEC com mand fo r a specified
interface:
Switch# show mvr interface fastethernet0/2
224.0.1.1 DYNAMIC ACTIVE
This is an example of output fro m the show mvr interface privileged EXEC com mand whe n the
members keyword is i n clud ed :
Switch# show mvr interface fastethernet0/2 members
224.0.1.1 DYNAMIC ACTIVE
This is an example of output fro m the show mvr members privileged EX EC co mman d:
Switch# show mvr members
MVR Group IP Status Members
------------ ------ -------
224.0.1.1 ACTIVE Fa0/1(s), Fa0/2(d)
224.0.1.2 ACTIVE Fa0/1(s)
224.0.1.3 ACTIVE Fa0/1(s)
224.0.1.4 ACTIVE Fa0/1(s)
224.0.1.5 ACTIVE Fa0/1(s)
<output truncated>

Configuring IGMP Fil teri ng

In some environments, for example metropolitan or multiple-dwelling unit (MDU) installations, an
administ rator might want to contr ol the set of mu lticast gro ups to which a user on a switch port can
belong. This allows the administrator to control the distribution of multicast services, such as IP/TV,
based on some type of subscription or service plan. With the IGMP filtering feature, you can filter
multicast joins on a per-port basis by configuring IP multicast profiles and associating them with
individual switch ports. An IGM P profile can conta in one or more mu lticast gro ups and speci fies
whether access to the group is permitted or denied. If an IGMP profile denying access to a multicast
group i s app lie d to a swit ch p ort , t he I GMP j oin repor t re qu esti ng t he st rea m of I P mu ltic as t tra ffic is
dropped, and the port is not allowed to receiv e IP multicast traff ic from that group. If the filtering action
permits access to the multicast group, the IGMP report from the port is forwarded for normal processing.
IGMP filteri ng c on trol s only gro up spec ific quer y an d mem be rship rep ort s, i ncl udin g joi n and leave
reports. It does not control general IGMP queries. IGMP filtering has no relationship with the function
that directs the forwarding of IP multicast traffic. The filtering feature operates in the same manner
whether CGMP or MVR is used to forward the multicast traffic.
You can also set the maximum number of IGMP groups that a Layer 2 interface can join.