D-Link DXS-3326GSR - xStack Switch - Stackable, Руководство пользователя

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DXS-3326GSR Gigabit Layer 3 Switch
Max Response Time
(1-25)
< 10 >
Sets the maximum amount of time allowed before sending an IGMP response report.
A value between
1 and 25 seconds can be entered, with a default of 10 seconds.
Robustness Variable
(1-255)
< 2 >
A tuning variable to allow for subnetworks that are expected to lose a large number of
packets. A value between
2 and 255 can be entered, with larger values being
specified for subnetworks that are expected to lose larger numbers of packets.
Last Member Query
Interval (1-25)
< 1 >
Specifies the maximum amount of time between group-specific query messages,
including those sent in response to leave group messages. A value between
1 and 25 .
The default is 1 second.
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 Global Settings
To enable DVMRP globally on the Switch, open the IP Multicast Routing Protocol folder in the Configuration folder,
and click the DVMR Configuration link. This will give the user access to the following screen:
Figure 7- 50. DVMRP Global Settings window
Use the pull-down menu, choose Enabled , and click Apply to implement the DVMRP function on the Switch.
DVMRP Interface Settings
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. DVMRP builds a
routing table to calculate 'shortest paths' back to the source of a multicast message and defines "route cost" (it is similar to,
but not defined as, the hop count in RIP) as a relative number that represents the real cost of using this route in the
construction of a multicast delivery tree 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.
To view the DVMRP Interface Settings window, open the IP Multicast Routing Protocol folder under Configuration
and click DVMRP Interface Settings . This window 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 Settings window. To configure DVMRP for a particular interface, click the corresponding
hyperlink for that IP interface. This will open the DVMRP Interface Settings window:
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