HP 6125XLG R2306-HP 6125XLG Blade Switch IP Multicast Configuration Guide - Page 78

Enabling the state refresh feature, Configuring state refresh parameters

Page 78 highlights

Enabling the state refresh feature 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 shared-media subnet can have the state refresh feature only if the state refresh feature is enabled on all PIM routers on the subnet. To enable the state refresh feature on all routers in PIM-DM domain: Step 1. Enter system view. 2. Enter interface view. 3. Enable the state refresh feature. Command system-view interface interface-type interface-number pim state-refresh-capable Remarks N/A N/A By default, the state refresh feature is enabled. 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 on that router. A router might receive duplicate state refresh messages within a short time. To prevent this situation, you can configure the amount of time that the router must wait before it receives next state refresh message. If the router receives a new state refresh message within the specified waiting time, it discards the message. If this timer times out, the router accepts a new state refresh message, refreshes its own PIM-DM state, and resets 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 might cycle in the network. To effectively control the propagation scope of state refresh messages, configure an appropriate TTL value based on the network size on the router directly connected with the multicast source. To configure state refresh parameters: Step 1. Enter system view. 2. Enter PIM view. 3. Configure the interval to send state refresh messages. 4. Configure the time to wait before receiving a new state refresh message. 5. Configure the TTL value of state refresh messages. Command system-view pim state-refresh-interval interval state-refresh-rate-limit time state-refresh-ttl ttl-value Remarks N/A N/A By default, the interval to send state refresh messages is 60 seconds. By default, the waiting time is 30 seconds. By default, the TTL value of state refresh messages is 255. 71

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71
Enabling the state refresh feature
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 shared-media subnet can have the state refresh feature only if the
state refresh feature is enabled on all PIM routers on the subnet.
To enable the state refresh feature on all routers in PIM-DM domain:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Enable the state refresh
feature.
pim state-refresh-capable
By default, the state refresh
feature is enabled.
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 on that router.
A router might receive duplicate state refresh messages within a short time. To prevent this situation, you
can configure the amount of time that the router must wait before it receives next state refresh message.
If the router receives a new state refresh message within the specified waiting time, it discards the
message. If this timer times out, the router accepts a new state refresh message, refreshes its own PIM-DM
state, and resets 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 might cycle in the network. To effectively control the propagation scope of state refresh
messages, configure an appropriate TTL value based on the network size on the router directly connected
with the multicast source.
To configure state refresh parameters:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter PIM view.
pim
N/A
3.
Configure the interval to send state
refresh messages.
state-refresh-interval
interval
By default, the interval to send
state refresh messages is 60
seconds.
4.
Configure the time to wait before
receiving a new state refresh
message.
state-refresh-rate-limit
time
By default, the waiting time is
30 seconds.
5.
Configure the TTL value of state
refresh messages.
state-refresh-ttl
ttl-value
By default, the TTL value of
state refresh messages is 255.