The mpls rsvp-te retrans-timer challenge command sets the interval at which Challenge messages are resent.
The undo mpls rsvp-te retrans-timer challenge command restores the default interval.
By default, the interval at which Challenge messages are resent is 1000 milliseconds.
Usage Scenario
If Authentication messages exchanged between two RSVP nodes are out of order, a node sends Challenge messages to the other one to request to restore the connection. If no reply to the Challenge message is received, the node resends Challenge messages at set intervals.