HP A5500 SI Switch Series Configuration Manual page 383

LAN_Prune_Delay—Delay of prune messages on a multi-access network. This option consists of
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LAN-delay (namely, prune message delay), override-interval, and neighbor tracking flag. If the
LAN-delay or override- interval values of different IPv6 PIM routers on a multi-access subnet are
different, the largest value will take effect. If you want to enable neighbor tracking on a router, be
sure to enable the neighbor tracking feature on all IPv6 PIM routers on a multi-access subnet.
The LAN-delay setting causes the upstream routers to delay processing received prune messages. The
override-interval sets the length of time that a downstream router will wait before sending a prune
override message. When a router receives a prune message from a downstream router, it does not
perform the prune action immediately. Instead, it maintains the current forwarding state for a period of
LAN-delay plus override-interval. If the downstream router needs to continue receiving IPv6 multicast
data, it must send a join message within the prune override interval. Otherwise, the upstream route will
perform the prune action when the period of LAN-delay plus override-interval times out.
A hello message sent from an IPv6 PIM router contains a generation ID option. The generation ID is a
random value for the interface on which the hello message is sent. Normally, the generation ID of an
IPv6 PIM router does not change unless the status of the router changes—for example, when IPv6 PIM is
just enabled on the interface or the device is restarted. When the router starts or restarts sending hello
messages, it generates a new generation ID. If an IPv6 PIM router finds that the generation ID in a hello
message from the upstream router has changed, it assumes that the status of the upstream neighbor is
lost or that the upstream neighbor has changed. In this case, it triggers a join message for state update.
If you disable join suppression—namely, enable neighbor tracking—on a router, be sure to disable the
join suppression feature on all IPv6 PIM-enabled routers on the same multi-access subnet. Otherwise, the
upstream router will fail to explicitly track which downstream routers have joined to it.
Configuring hello options globally
Follow these steps to configure hello options globally:
To do...
Enter system view
Enter IPv6 PIM view
Configure the priority for DR
election
Configure IPv6 PIM neighbor
timeout time
Configure the prune message
delay time (LAN-delay)
Configure the prune override
interval
Disable join suppression
Configuring hello options on an interface
Follow these steps to configure hello options on an interface:
To do...
Enter system view
Use the command...
system-view
pim ipv6
hello-option dr-priority priority
hello-option holdtime interval
hello-option lan-delay interval
hello-option override-interval
interval
hello-option neighbor-tracking
Use the command...
system-view
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Remarks
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—
Optional
1 by default
Optional
105 seconds by default
Optional
500 milliseconds by default
Optional
2,500 milliseconds by default
Required
Enabled by default
Remarks
—