24-Port Layer 3 Switch Management Guide

M ULTICAST R OUTING
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The global settings that control the prune and graft messages (i.e., prune
lifetime) should be configured to the same values on all routers throughout
the network to allow DVMRP to function properly. However, if you
encounter problems in maintaining a multicast flow, then you may need 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)
• Neighbor Timeout Interval – Sets the interval to wait for messages
from a DVMRP neighbor before declaring it dead. This command is used
for timing out routes, and for setting the children and leaf flags. (Range:
1-65535 seconds; Default: 35 seconds)
• Report Interval – Specifies how often to propagate the complete set of
routing tables to other neighbor DVMRP routers. (Range: 1-65535
seconds; Default: 60 seconds)
• Flash Update Interval – Specifies how often to send trigger updates,
which reflect changes in the network topology.
• Prune Lifetime – Specifies how long a prune state will remain in effect
for a multicast tree. (Range: 1-65535; Default: 7200 seconds)
• Default Gateway* – Specifies the default DVMRP gateway for IP
multicast traffic. (Default: none)
- The specified interface advertises itself as a default route to
neighboring DVMRP routers. It advertises the default route out
through its other interfaces. Neighboring routers on the other
interfaces return Poison Reverse messages for the default route back