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
Upstream router prune
A network may have multiple routing switches sharing VLAN "X". When an upstream routing switch initially floods
traffic from multicast group "X" to VLAN "Y", if one of the routing switches 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 prune pending period, another routing switch on VLAN "Y" can send a group "X" Join to the upstream
neighbor. If this happens, the upstream neighbor drops the prune pending state and continues forwarding the
traffic. If no routers on the VLAN send a Join, the upstream router prunes group "X" from VLAN "Y" when the lan-
prune-delay timer expires.
58
Aruba 3810 / 5400R Multicast and Routing Guide for ArubaOS-
Switch 16.08