D-Link DGS-3324SRi Intelligent Stackable Gigabit Ethernet Switch
122
State <
Disabled
>
This field can be toggled between
Enabled
and
Disabled
and enables or
disables IGMP for the IP interface. The default is
Disabled
.
DVMRP Interface Configuration
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.
DVMRP Global Setting
To enable DVMRP globally on the Switch, open the
IP Multicast Routing Protocol
folder in the
Configuration
folder, and click the
DVMRP Configuration
link. This will give the user access to the following
screen:
Figure 4- 85. DVMRP Global Setting window
Use the pull down menu, choose
Enabled
, and click
Apply
to set the DVMRP function on the Switch.
DVMRP Interface Settings
To view the
DVMRP Interface Table
, open the
IP Multicasting
folder under
Configuration
and click
DVMRP Interface Settings
. This menu allows the
Distance-Vector Multicast Routing Protocol (DVMRP)
to
be configured for each IP interface defined on the Switch. Each IP interface configured on the Switch is
displayed in the below
DVMRP Interface Configuration
dialog box. To configure DVMRP for a particular
interface, click the corresponding hyperlink for that IP interface. This will open the
DVMRP Interface
Configuration
window:
Figure 4- 86. DVMRP Interface Table
