To make new members in a network to quickly receive multicast data, a multicast device actively sends a Graft message through an upstream interface, requesting the upstream device to forward multicast data to this network segment.
Before configuring control parameters for graft, complete the following tasks:
Configuring a unicast routing protocol
In a PIM-DM network, if State-Refresh is not enabled, a pruned interface can forward packets after the Prune state times out. If State-Refresh is enabled, the pruned interface may never forward packets.
To enable new members in the network to receive multicast data quickly, a PIM-DM device sends a Graft message through an upstream interface. After receiving the Graft message, the upstream FW responds immediately with a Graft-Ack message and enables the interface that receives the Graft message to forward packets.
FWs can work normally under the control of the default parameter values. Users can adjust the related parameters according to the specific network environment.
interface interface-type interface-number
pim timer graft-retry interval
If the local FW does not receive any Graft-Ack message from the upstream FW in a specified period, it resends a Graft message.