Ericsson ECN330, User Manual

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Configuring the ECN330-switch
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If the router that previously sent a prune message now discovers a new group
member on one of its connections, it sends a graft message to the upstream
router. When an upstream router receives this message, it cancels the prune
message. If necessary, graft messages are propagated back toward the source
until reaching the nearest live branch in the multicast tree.
Figure 219 DVMRP Grafting
The global settings that control the prune and graft messages (that is, prune
lifetime) should be configured to the same values on all routers throughout the
network to allow DVMRP to function properly. However, if problems are
encountered in maintaining a multicast flow, then it may be necessary to modify
the protocol variables which control the exchange of topology information
between DVMRP routers; such as the probe interval, neighbor timeout or report
interval.
Command Attributes
• DVMRP Protocol – Enables/disables DVMRP globally. (Default:
Disabled)
• Probe Interval – Sets the interval for sending neighbor probe
messages to the multicast group address for all DVMRP routers. Probe
messages are sent to neighboring DVMRP routers from which this
device has received probes, and is used to verify whether or not these
neighbors are still active members of the multicast tree. (Range: 1-
65535 seconds; Default: 10 seconds)
grafting
source