c-bsr interval (IPv4)

Function

The c-bsr interval command configures the interval for the BootStrap router (BSR) to continuously send Bootstrap messages.

The undo c-bsr interval command restores the default configuration.

Format

c-bsr interval interval

undo c-bsr interval

Parameters

Parameter	Description	Value
interval	Specifies the interval for the BSR to continuously send the Bootstrap messages.	The value is an integer that ranges from 1 to 107374177, in seconds.

Views

PIM view

Default Level

2: Configuration level

Usage Guidelines

By default, the interval for the BSR to continuously send Bootstrap messages is 60s.

Usage Scenario

The interval for sending Bootstrap messages is BS_interval, which can be configured using the c-bsr interval command. After a Candidate-BootStrap Router (C-BSR) is elected as the BSR, the C-BSR periodically sends Bootstrap messages carrying the IP address of the C-BSR and the Rendezvous Point (RP)-set information to the network.

Other C-BSRs that fail in the election are suppressed from sending Bootstrap messages and start the timer to monitor the BSR. The timeout period of a timer is holdtime, which can be configured using the c-bsr holdtime command. The following applies to the timer:

If the C-BSR receives the Bootstrap messages sent by the BSR, the C-BSR refreshes the timer.
If the timer times out, the BSR is considered to be faulty. The C-BSRs that fail in the election triggers a new round of BSR election. Therefore, services are not interrupted.

Prerequisites

The multicast routing-enable command has been run.

Configuration Impact

This command is cyclical in nature. That is, the latest command overwrites the previous one, and takes effect.

Precautions

In actual applications, all C-BSRs in the same PIM domain must use the same BS_interval and holdtime. If the configured values are different, the BSR may become unstable. This may result in a multicast fault. Note the following points:

If BS_interval and holdtime are configured at the same time, ensure that BS_interval is less than holdtime.
If only one of the BS_interval and holdtime is configured, use the following formula to calculate the other parameter: holdtime = 2 x BS_interval + 10. The following determines which value is used:
- If holdtime is configured and the calculated BS_interval is less than the minimum value of BS_interval, the minimum value is used.
- If BS_interval is configured and the calculated holdtime is less than the maximum value of holdtime, the maximum value is used.
If neither the BS_interval nor the holdtime is configured, default values are used. The default value of BS_interval is 60s, and the default value of holdtime is 130s.

Example

# Set the interval for the C-BSR to continuously send Bootstrap messages to 30 seconds.

<sysname> system-view
[sysname] multicast routing-enable
[sysname] pim
[sysname-pim] c-bsr interval 30