KB.15.15

NOTE: Not used with the [no] form of the ip pim-dense command.

Default: 3 attempts

Enabling the LAN prune delay option on the current VLAN

Syntax:

ip pim-dense [lan-prune-delay]

vlan[vid]ip pim-dense [lan-prune-delay]

Enables the LAN prune delay option on the current VLAN. With lan-prune-delay

enabled, the routing switch informs downstream neighbors how long it will wait

before pruning a flow after receiving a prune request. Other, downstream routers

on the same VLAN must send a Join request to override the prune before the

lan-prune-delay times out if they want the flow to continue. This prompts any

downstream neighbors with hosts continuing to belong to the flow to reply with a

Join. If no joins are received after the LAN prune-delay period, the routing switch

prunes the flow.

The propagation-delay and override-interval settings determine the lan-prune-delay

setting.

NOTE: Uses the [no] form of the ip pim-dense command to disable the LAN

prune delay option.

Default: Enabled

Computing the lan-prune-delay setting

Syntax:

ip pim-dense [propagation-delay[250-2000]]

vlan[vid]ip pim-dense [propagation-delay[250-2000]]

ip pim-dense [override-interval[500-6000]]

vlan [vid]ip pim-dense [override-interval[500-6000]]

A routing switch sharing a VLAN with other multicast routers uses these two values

to compute the lan-prune-delay setting for how long to wait for a PIM-DM Join after

receiving a prune packet from downstream for a particular multicast group.

Defaults: propagation-delay=500 milliseconds; override-interval = 2500 milliseconds

42 PIM-DM (Dense Mode)