Dell PowerConnect 7048P Manual page 1146

• 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 7000 Series 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.
1146
Managing IPv4 and IPv6 Multicast