Dell PowerEdge M420 Configuration Manual page 1158

• The branches that transmit a prune message are deleted from the delivery
tree.
• The delivery tree which is spanning to all the members in the multicast
group, is constructed in the form of a DVMRP forwarding table.
Using DVMRP as the Multicast Routing Protocol
DVMRP is used to communicate multicast information between L3 switches
or routers. If a PowerConnect M6220/M6348/M8024/M8024-k switch handles
inter-VLAN routing for IP traffic, including IP multicast traffic, multicast
routing might be required on the switch.
DVRMP is best suited for small networks where the majority of hosts request
a given multicast traffic stream. DVMRP is similar to PIM-DM in that it
floods multicast packets throughout the network and prunes branches where
the multicast traffic is not desired. DVMRP was developed before PIM-DM,
and it has several limitations that do not exist with PIM-DM.
You might use DVMRP as the multicast routing protocol if it has already been
widely deployed within the network.
1158
Managing IPv4 and IPv6 Multicast