20-18
Catalyst 2960 Switch SoftwareConfiguration Guide
78-16881-01
Chapter20 Configuring IGMP Snooping and MVR
Configuring MVR
These messages dynamically register for streams of multicast traffic in the multicast VLAN on the
Layer 3 device. Switch B. The access layer switch, Switch A, modifies the forwarding behavior to allow
the traffic to be forwarded from the multicast VLAN to the subscriber port in a different VLAN,
selectively allowing traffic to cross between two VLANs.
IGMP reports are sent to the same IP multicast group addr ess as the multicast data. The Switch A CPU
must capture all IGMP join and leave messages from receiver ports and forward them to the multicast
VLAN of the source (uplink) port, based on the MVR mod e.
Configuring MVR
These sections contain this configuration information:
Default MVR Configuration, page 20-18
MVR Configuration Guidelines and Limitations, page 20-18
Configuring MVR Global Parameters, page 20-19
Configuring MVR Interfaces, page 20-20

Default MVR Configuration

Table20-5 shows the default MVR configuration.

MVR Configuration Guidelines and Limitations

Follow these guidelines when configuring MVR:
Receiver ports can only be access ports; they cannot be trunk ports. Receiver ports on a switch can
be in different VLANs, but should not belong to the multicast VLAN.
The maximum number of multicast entries (MVR group addresses) that can be configured on a
switch (that is, the maximum number of television channels that can be received) is 256.
MVR multicast data received in the source VLAN and leaving from receiver ports has its
time-to-live (TTL) decremented by 1 in the switch.
Table20-5 Default MVR Configuration
Feature Default Setting
MVR Disabled globally and per interface
Multicast addresses None configured
Query response time 0.5 second
Multicast VLAN VLAN 1
Mode Compatible
Interface (per port) default Neither a receiver nor a source port
Immediate Leave Disabled on all ports