Configuring State Refresh Parameters; Configuring Pim-Dm Graft Retry Period - 3Com MSR 50 Series Configuration Manual

Configuring State
Refresh Parameters
Configuring PIM-DM
Graft Retry Period
To do...
Enable state refresh
To avoid the resource-consuming reflooding of unwanted traffic caused by
timeout of pruned interfaces, the router directly connected with the multicast
source 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 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 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.
Follow these steps to configure state refresh parameters:
To do...
Enter system view
Enter public instance PIM view
or VPN instance PIM view
Configure the interval
between state refresh
messages
Configure the time to wait
before receiving a new state
refresh message
Configure the TTL value of
state refresh messages
In PIM-DM, graft is the only type of message that uses the acknowledgment
mechanism. In a PIM-DM domain, if a router does not receive a graft-ack message
from the upstream router within the specified time after it sends a graft message,
the router keeps sending new graft messages at a configurable interval, namely
graft retry period, until it receives a graft-ack from the upstream router.
Follow these steps to configure graft retry period:
To do...
Enter system view
Use the command...
pim state-refresh-capable
Use the command...
system-view
pim [ vpn-instance
vpn-instance-name ]
state-refresh-interval
interval
state-refresh-rate-limit
interval
state-refresh-ttl ttl-value
Use the command...
system-view
Configuring PIM-DM 1175
Remarks
Optional
Enabled by default
Remarks
-
-
Optional
60 seconds by default
Optional
30 seconds by default
Optional
255 by default
Remarks
-