H3C Technologies H3C SecPath F1000-E - Manual (Page 111)

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NOTE:
For more information about the multicast routing-enable command, see Multicast Routing and
Forwarding Commands in the IP Multicast Volume.
Enabling State-Refresh Capability
Pruned interfaces resume multicast forwarding when the pruned state times out. To prevent this, the router
with the multicast source attached periodically sends an (S, G) state-refresh message, which is forwarded
hop by hop along the initial multicast flooding path of the PIM-DM domain, to refresh the prune timer
state of all the routers on the path. A multi-access subnet 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 the state-refresh capability 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 discards 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, 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 network PIM view pim —
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