3.1.6.1 Connect Retry Timer

When the Connect Retry Timer expires, a new CONNECT message SHOULD be sent if it is an outbound connection that has not yet received a response from the listener; otherwise, for all other cases where the Connect Retry Timer is active a new CONNECTED message SHOULD be sent. The Connect Retry Timer SHOULD then be rescheduled for the next period. It is recommended that the retry period starts at 200 milliseconds and doubles every time, with a maximum of 5 seconds and 14 retries.

If the maximum number of retries has already been attempted when the timer expires, the connection attempt MUST be considered as failed. If the connection was initiated from an inbound CONNECT packet arriving on a listening computing system, the listener MAY choose to go back to listening if it did not allow additional connection attempts while the failed attempt was in progress.