This read-create value, in seconds and ranging 0 to 65535 with a default of 150, sets how long this Candidate-RP entry remains valid at the BSR after being advertised. It determines how quickly the BSR will time out and remove this RP candidate if advertisements stop arriving, directly affecting multicast failover speed. An admin tuning for faster RP failure detection would lower this holdtime relative to the advertisement interval so a missed advertisement or two triggers expiration sooner.