Dvmrp Interface Configuration - D-Link DES-3326SR Manual

D-Link DES-3326SR Layer 3 Switch

DVMRP Interface Configuration

To configure DVMRP for an IP interface, Click the DVMRP Interface Configurations link from the IP Multicast
Routing Protocols folder:
Figure 21- 6. DVMRP Interface Configuration
Figure 21- 7. DVMRP Interface Configuration − Edit
This menu allows the Distance-Vector Multicast Routing Protocol to be configured for each IP interface defined
on the switch.
The Distance Vector Multicast Routing Protocol (DVMRP) is a hop-based method of building multicast
delivery trees from multicast sources to all nodes of a network. Because the delivery trees are 'pruned' and
'shortest path', DVMRP is relatively efficient. Because multicast group membership information is forwarded by
a distance-vector algorithm, propagation is slow. DVMRP is optimized for high delay (high latency) relatively
low bandwidth networks, and can be considered as a 'best-effort' multicasting protocol.
DVMRP resembles the Routing Information Protocol (RIP), but is extended for multicast delivery. It relies upon
RIP hop counts to calculate 'shortest paths' back to the source of a multicast message, but defines a 'route cost'
to calculate which branches of a multicast delivery tree should be 'pruned' – once the delivery tree is established.
When a sender initiates a multicast, DVMRP initially assumes that all users on the network will want to receive
the multicast message. When an adjacent router receives the message, it checks its unicast routing table to
determine the interface that gives the shortest path (lowest cost) back to the source. If the multicast was received
over the shortest path, then the adjacent router enters the information into its tables and forwards the message. If
the message is not received on the shortest path back to the source, the message is dropped.
Route cost is a relative number that is used by DVMRP to calculate which branches of a multicast delivery tree
should be 'pruned'. The 'cost' is relative to other costs assigned to other DVMRP routes throughout the network.
The higher the route cost, the lower the probability that the current route will be chosen to be an active branch of
the multicast delivery tree (not 'pruned') – if there is an alternative route.
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