Adjusting Time Parameters for Join/Prune Messages

Context

A multicast device sends Join messages upstream to require forwarding of multicast data, and Prune messages upstream to stop the forwarding of multicast data. Join information and prune information are encapsulated in Join/Prune messages. The PIM device periodically sends Join/Prune messages to an upstream device to update the forwarding state. When the upstream device receives a Join/Prune message, it starts a timer and sets the timer value to the holdtime of the Join/Prune message. If the device does not receive any Join/Prune message before the timer expires, it acts as follows:

If the previously received Join/Prune message is sent by a host to join a multicast group, the device stops sending multicast data to the downstream interface of the multicast group.
If the previously received Join/Prune message is sent to prune the downstream interface of a multicast group, the device starts to send multicast data packets to the downstream interface.

Therefore, the interval for sending Join/Prune messages must be smaller than the holdtime of a Join/Prune message.

The interval for sending Join/Prune messages and the holdtime of Join/Prune messages can be set globally or on an interface. If the two parameters are configured in both the global PIM view and interface view, the configuration in the interface view takes effect.

Default Settings

Table 1 lists the default settings of time parameters for Join/Prune messages.

**Table 1** Default settings of time parameters for Join/Prune messages
Parameter	Default Setting
Interval for sending Join/Prune messages	60s
Holdtime of Join/Prune messages	210s

Procedure

Global configuration
1. Run system-view
  The system view is displayed.
2. Run pim [ vpn-instance vpn-instance-name | all-instance ]
  The PIM view is displayed.
3. Run timer join-prune interval
  The interval for sending Join/Prune messages is configured.
4. Run holdtime join-prune interval
  The holdtime of Join/Prune messages is configured.
Configuration on an interface
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
4. Run pim timer join-prune interval
  The interval for sending Join/Prune messages is configured.
5. Run pim holdtime join-prune interval
  The holdtime of Join/Prune messages is configured.