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•
Holdtime
—IPv6 PIM neighbor lifetime. If a router receives no hello message from a neighbor when
the neighbor lifetime expires, it regards the neighbor failed or unreachable.
•
LAN_Prune_Delay
—Delay of forwarding prune messages on a shared-media LAN. This option
consists of LAN delay (namely, prune message delay), override interval, and neighbor tracking
support (namely, the capability to disable join message suppression).
The prune message delay defines the delay time for a router to forward a received prune message
to the upstream routers. The override interval defines a time period for a downstream router to
override a prune message. If the prune message delay or override interval on different IPv6 PIM
routers on a shared-media LAN are different, the largest value takes effect.
A router does not immediately prune an interface after it receives a prune message from the
interface. Instead, it starts a timer (the prune message delay plus the override interval). If interface
receives a join message before the override interval expires, the router does not prune the
interface. Otherwise, the router prunes the interface when the timer (the prune message delay plus
the override interval) expires.
You can enable the neighbor tracking function (or disable the join message suppression function)
on an upstream router to track the states of the downstream nodes that have sent the join message
and the joined state holdtime timer has not expired. If you want to enable the neighbor tracking
function, you must enable it on all IPv6 PIM routers on a shared-media LAN. Otherwise, the
upstream router cannot track join messages from every downstream routers.
•
Generation ID
—A router generates a generation ID for hello messages when an interface is
enabled with IPv6 PIM. The generation ID is a random value, but only changes when the status of
the router changes. 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 router has changed. In this
case, it sends a join message to the upstream router for status update. You can configure an
interface to drop hello messages without the generation ID options to promptly know the status of an
upstream router.
Configuring hello options globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IPv6 PIM view.
pim ipv6
N/A
3.
Set the DR priority.
hello-option dr-priority
priority
Optional.
1 by default.
4.
Set the neighbor lifetime.
hello-option holdtime
interval
Optional.
105 seconds by default.
5.
Set the prune message delay.
hello-option lan-delay
interval
Optional.
500 milliseconds by default.
6.
Set the override interval.
hello-option override-interval
interval
Optional.
2500 milliseconds by default.
7.
Enable the neighbor tracking
function.
hello-option neighbor-tracking
Disabled by default.
