H3C Technologies H3C S7500E Series Switches - Manual (Page 155)

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can have the state-refresh capability only if the state-refresh capability is enabled on all PIM
routers on the subnet.
Follow these steps to enable the state-refresh capability:
To do... Use the command... Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Enable state-refresh pim state-refresh-capable
Optional
Enabled by default
Configuring State-Refresh Parameters
The router directly connected with the multicast source periodically sends state-refresh
messages. You can configure the interval for sending such messages.
A router may receive multiple state-refresh messages within a short time, of which some may
be duplicated messages. To keep a router from receiving such duplicated messages, you can
configure the time the router must wait before receiving the next state-refresh message. If a
new state-refresh message is received within the waiting time, the router will discard it; if this
timer times out, the router will accept a new state-refresh message, refresh its own PIM-DM
state, and reset the waiting timer.
The TTL value of a state-refresh message decrements by 1 whenever it passes a router before
it is forwarded to the downstream node until the TTL value comes down to 0. In a small network,
a state-refresh message may cycle in the network. To effectively control the propagation scope
of state-refresh messages, you need to configure an appropriate TTL value based on the
network size.
It is recommended to perform the following configurations on all routers in the PIM domain.
Follow these steps to configure state-refresh parameters:
To do... Use the command... Remarks
Enter system view system-view —
Enter public instance PIM view or VPN
instance PIM view
pim [ vpn-instance
vpn-instance-name ]
—
Configure the interval between
state-refresh messages
state-refresh-interval
interval
Optional
60 seconds by default
Configure the time to wait before
receiving a new state-refresh message
state-refresh-rate-limit
interval
Optional
30 seconds by default
Configure the TTL value of
state-refresh messages
state-refresh-ttl ttl-value
Optional
255 by default