Configuring L2 Multicast Features 685There are two configured learning modes of the MVR operation: dynamic andcompatible.• In the dynamic mode MVR learns existent multicast groups by parsing theIGMP queries from router on source ports and forwarding the IGMP joinsfrom the hosts to the router.• In the compatible mode MVR does not learn multicast groups, but theyhave to be configured by administrator and protocol does not forward joinsfrom the hosts to the router. To work in this mode the IGMP router has tobe configured to transmit required multicast streams to the network withthe MVR switch.Enabling MVR and IGMP on the Same InterfaceMVR and IGMP snooping operate independently and could both be enabledon an interface. When both MVR and IGMP snooping are enabled, MVRlistens to the IGMP join and report messages for static multicast groupinformation, 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 multicastfeatures. You configure the IP/IPv6 multicast features if the switch functionsas a multicast router that can route multicast traffic between VLAN routinginterfaces. In this case, you must enable a multicast routing protocol on theswitch, such as PIM-SM. For information about L3 multicast features, see"Managing IPv4 and IPv6 Multicast" on page 1157.If you enable IGMP Snooping on the switch to listen to IGMP traffic, you donot need to enable IGMP, a layer 3 multicast protocol. If the switch functionsas a multicast router, it is possible to enable both IGMP and IGMP Snoopingso that the switch routes IGMP traffic between VLANs and examines theIGMP packets for join and leave information.For information about configuring a PowerConnect 8000-series and 8100-series switches as a mutlicast router that also performs IGMP snooping, see"Configuring Multicast VLAN Routing With IGMP and PIM-SM" onpage 1231.NOTE: If MVR is enabled, IP Multicast should be disabled. Multicast routing andMVR cannot coexist on a switch.
