20-18
Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
78-17058-01
Chapter20 Configuring IGMP Snooping and MVR
Configuring MVR
IGMP leave was received. As soon as the leave message is received, the receiver port is removed from
multicast group membership, which speeds up leave latency. Enable the Immediate-Leave feature only
on receiver ports to which a single receiver device is connected.
MVR eliminates the need to duplicate television-channel multicast traff ic for subscrib ers in each VLAN.
Multicast traffic for all channels is only sent around the VLAN trunk once—only on the multicast
VLAN. The IGMP leave and join messages are in the VLAN to which the subscriber port is assigned.
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 20-19
•Configuring MVR Global Parameters, page 20-19
•Configuring MVR Interfaces, page 20-20

Default MVR Configuration

Table20-5 shows the default MVR configuration.
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