ip pim-sparse override-interval

Syntax

ip pim-sparse override-interval <INTERVAL-VALUE>

no ip pim-sparse override-interval 

Description

Configures the override interval that gets inserted into the Override Interval field of a LAN Prune Delay option.

The no form of this command removes the currently configured value and sets the value to the default of 2500 ms.

Command context

config-if

config-if-vlan

config-lag-if

Parameters

<INTERVAL-VALUE>

Specifies the override interval of a LAN Prune Delay option in ms. Default: 2500 ms. Range: 500-6000.

Authority

Administrators

Usage

A router sharing a VLAN with other multicast routers uses the override-interval value along with the propagation-delay value to compute the lan-prune-delay setting. The setting specifies how long to wait for a PIM-SM join after receiving a prune packet from downstream for a particular multicast group.

Example scenario:

A network may have multiple routers sharing VLAN X. When an upstream router is forwarding traffic from multicast group X to VLAN Y, if one of the routers on VLAN Y does not want this traffic, it issues a prune response to the upstream neighbor. The upstream neighbor then goes into a prune pending state for group X on VLAN Y. During this period, the upstream neighbor continues to forward the traffic. During the pending period, another router on VLAN Y can send a group X join to the upstream neighbor. If this happens, the upstream neighbor drops the prune pending status and continues forwarding the traffic. But if no routers on the VLAN send a join, the upstream router prunes.

Example

Configuring and removing the override interval:

switch(config)# interface vlan40
switch(config-if-vlan)# ip pim-sparse override-interval 4000
switch(config-if-vlan)# no ip pim-sparse override-interval