3com S7906E Instruccion De Instalación

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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 

— 

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 

 

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... 

Use the command... 

Remarks  

Enter system view 

— 

Enter interface view 

interface interface-type 
interface-number 

— 

Configure graft retry period  

pim timer graft-retry interval 

Optional 

3 seconds by default  

 

For the configuration of other timers in PIM-DM, refer to 

.