H3C Technologies H3C S7500E Series Switches - Manual (Page 383)

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To do… Use the command… Remarks
Enter interface view
interface interface-type
interface-number
—
Configure a hello message
filter
pim ipv6 neighbor-policy
acl6-number
Required
No hello message filter by
default.
With the hello message filter configured, if hello messages of an existing IPv6 PIM neighbor fail
to pass the filter, the IPv6 PIM neighbor will be removed automatically when it times out.
Configuring IPv6 PIM Hello Options
No matter in an IPv6 PIM-DM domain or an IPv6 PIM-SM domain, the hello messages sent
among routers contain many configurable options, including:
z DR_Priority (for IPv6 PIM-SM only): priority for DR election. The higher the priority is, the
easier it is for the router to win DR election. You can configure this parameter on all the
routers in a multi-access network directly connected to IPv6 multicast sources or receivers.
z Holdtime: the timeout time of IPv6 PIM neighbor reachability state. When this timer times
out, if the router has received no hello message from an IPv6 PIM neighbor, it assumes that
this neighbor has expired or become unreachable.
z LAN_Prune_Delay: the delay of prune messages on a multi-access network. This option
consists of Lan-delay (namely, message prune 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, the neighbor tracking feature should be enabled on all IPv6 PIM routers
on a multi-access subnet.
The LAN-delay setting will cause the upstream routers to delay processing received prune
messages.
The override-interval sets the length of time a downstream router is allowed to 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 prune override message
within the prune override interval; otherwise, the upstream route will perform the prune action
when the period of LAN-delay plus override-interval time 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