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Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter PIM view.
pim
[
vpn-instance
vpn-instance-name
]
N/A
3.
Configure a multicast source
policy.
source-policy ipv4-acl-number
By default, no multicast source
policy exists. The device does not
filter multicast data packets.
Configuring a PIM hello policy
This feature enables the device to filter PIM hello messages by using an ACL that specifies the
packet source addresses. It is used to guard against PIM message attacks and to establish correct
PIM neighboring relationships.
If hello messages of an existing PIM neighbor are filtered out by the policy, the neighbor is
automatically removed when its aging timer expires.
To configure a PIM hello policy:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Configure a PIM hello policy.
pim neighbor-policy
ipv4-acl-number
By default, no PIM hello policy
exists on an interface, and all PIM
hello messages are regarded as
legal.
Configuring PIM hello message options
In either a PIM-DM domain or a PIM-SM domain, hello messages exchanged among routers contain
the following configurable options:
•
DR_Priority
(for PIM-SM only)—Priority for DR election. The device with the highest priority
wins the DR election. You can configure this option for all the routers in a shared-media LAN
that directly connects to the multicast source or the receivers.
•
Holdtime
—PIM neighbor lifetime. If a router does not receive a hello message from a neighbor
when the neighbor lifetime expires, it regards the neighbor failed or unreachable.
•
LAN_Prune_Delay
—Delay of pruning a downstream interface on a shared-media LAN. This
option has LAN delay, override interval, and neighbor tracking support (the capability to disable
join message suppression).
The LAN delay defines the PIM message propagation delay. The override interval defines a
period for a router to override a prune message. If the propagation delay or override interval on
different PIM routers on a shared-media LAN are different, the largest ones apply.
On the shared-media LAN, the propagation delay and override interval are used as follows:
If a router receives a prune message on its upstream interface, it means that there are
downstream routers on the shared-media LAN. If this router still needs to receive multicast
data, it must send a join message to override the prune message within the override
interval.
When a router receives a prune message from its downstream interface, it does not
immediately prune this interface. Instead, it starts a timer (the propagation delay plus the
