HP 3500YL - Manual (Page 137)

PIM-SM (Sparse Mode)
Configuring PIM-SM on the Router
Changing the LAN-Prune-Delay Interval
Syntax: ip pim-sparse propagation-delay < 250-2000 >
vlan < vid > ip pim-sparse propagation-delay < 250-2000 >
ip pim-sparse override-interval < 500 - 6000 >
vlan < vid > ip pim-sparse override-interval < 500 - 6000 >
A router sharing a VLAN with other multicast routers uses
these two values to compute the
lan-prune-delay setting
(above) for how long to wait for a PIM-SM join after
receiving a prune packet from downstream for a particular
multicast group. For example, 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” state and
continues forwarding the traffic. But if no routers on the
VLAN send a Join, then the upstream router prunes group
“X” from VLAN “Y” when the
lan-prune-delay timer expires.
(Defaults: propagation-delay = 500 milliseconds; override-
interval = 2500 milliseconds.)
Changing the DR (Designated Router) Priority
Syntax: ip pim-sparse dr-priority < 0 - 4294967295 >
This command changes the router priority for the DR
(Designated Router) election process in the current VLAN. A
numerically higher value means a higher priority. If the
highest priority is shared by multiple routers in the same
VLAN, then the router with the highest IP address is selected
as the DR. A 0 (zero) value disables DR operation for the router
on the current VLAN.
(Range: 0 - 2147483647; Default: 1)
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