Configuring L2 Multicast Features 707
• In the compatible mode MVR does not learn multicast groups, but they 
have to be configured by administrator and protocol does not forward joins 
from the hosts to the router. To work in this mode the IGMP router has to 
be configured to transmit required multicast streams to the network with 
the MVR switch.
Enabling MVR and IGMP on the Same Interface
MVR and IGMP snooping operate independently and could both be enabled 
on an interface. When both MVR and IGMP snooping are enabled, MVR 
listens to the IGMP join and report messages for static multicast group 
information, and IGMP snooping manages dynamic multicast groups.
When Are L3 Multicast Features Required?
In addition to L2 multicast features, the switch suports IP and IPv6 multicast 
features. You configure the IP/IPv6 multicast features if the switch functions 
as a multicast router that can route multicast traffic between VLAN routing 
interfaces. In this case, you must enable a multicast routing protocol on the 
switch, such as PIM-SM. For information about L3 multicast features, see 
"Managing IPv4 and IPv6 Multicast" on page 1137.
If you enable IGMP Snooping on the switch to listen to IGMP traffic, you do 
not need to enable IGMP, a layer 3 multicast protocol. If the switch functions 
as a multicast router, it is possible to enable both IGMP and IGMP Snooping 
so that the switch routes IGMP traffic between VLANs and examines the 
IGMP packets for join and leave information.
For information about configuring a PowerConnect 7000 Series switch as a 
mutlicast router that also performs IGMP snooping, see "Configuring 
Multicast VLAN Routing With IGMP and PIM-SM" on page 1211.
NOTE: If MVR is enabled, IP Multicast should be disabled. Multicast routing and 
MVR cannot coexist on a switch.