c-bsr interval

To maintain the BSR status, a BSR dynamically elected among candidate-bootstrap routers (C-BSRs) needs to periodically send bootstrap messages carrying the BSR IP address and the rendezvous point (RP)-set information to the C-BSRs. To set the interval (called BS_interval) at which the BSR sends bootstrap messages, run the c-bsr interval command.

Only the BSR sends bootstrap messages, and each C-BSR starts a timer and waits to receive bootstrap messages from the BSR before the timer times out. The timeout period (called holdtime) of the timer can be configured using the c-bsr holdtime command.

• If a C-BSR receives a bootstrap message from the BSR, the C-BSR resets the timer.
• If a C-BSR does not receive a bootstrap message after the holdtime times out, the C-BSR considers the BSR faulty and triggers a new round of BSR election to prevent service interruptions.

You must set the same BS_interval and the same holdtime on all C-BSRs in the same PIM domain. Otherwise, a BSR may be frequently elected. Note the following points:

• If both the BS_interval and holdtime are set, ensure that BS_interval is smaller than holdtime.
• If only the BS_interval or holdtime is set, calculate the other one using the formula: Holdtime = 2 x BS_interval + 10.
• If the holdtime is configured and the calculated BS_interval is smaller than the minimum value of BS_interval, the minimum value of BS_interval is used.
• If the BS_interval is configured and the calculated holdtime is greater than the maximum value of holdtime, the maximum value of holdtime is used.
• The default BS_interval is 60 seconds, and the default holdtime is 130 seconds.