H3C Technologies H3C S10500 Series Switches - Manual (Page 388)

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NOTE:
For more information about the multicast ipv6 routing-enable command, see IP Multicast Command
Reference.
Enabling state-refresh capability
Pruned interfaces resume multicast forwarding when the pruned state times out. To prevent this, the router
directly connected with the IPv6 multicast source periodically sends an (S, G) state-refresh message,
which is forwarded hop by hop along the initial flooding path of the IPv6 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 IPv6 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 ipv6 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 might receive multiple state-refresh messages within a short time. Some messages might be
duplicated messages. To keep a router from receiving such duplicated messages, you can configure the
time that the router must wait before receiving the next state-refresh message. If the router receives a new
state-refresh message within the waiting time, it discards it. If this timer times out, the router will accept a
new state-refresh message, refresh its own IPv6 PIM-DM state, and reset the waiting timer.
The hop limit value of a state-refresh message decrements by 1 whenever it passes a router before it is
forwarded to the downstream node until the hop limit value comes down to 0. In a small network, a
state-refresh message might cycle in the network. To control the propagation scope of state-refresh
messages, you must configure an appropriate hop limit value based on the network size.
Perform the following configurations on all routers in the IPv6 PIM domain.
Follow these steps to configure state-refresh parameters:
To do... Use the command... Remarks
Enter system view system-view —
Enter IPv6 PIM view pim ipv6 —
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