Automatic job requeue occurs when a job finishes and has a specified exit code (usually indicating some type of failure).
Automatic job rerun occurs when the execution host becomes unavailable while a job is running. It does not occur if the job itself fails.
When a job is rerun or restarted, it is first returned to the queue from which it was dispatched with the same options as the original job. The priority of the job is set sufficiently high to ensure the job gets dispatched before other jobs in the queue. The job uses the same job ID number. It is executed when a suitable host is available, and an email message is sent to the job owner informing the user of the restart.
When LSF reruns a job, it returns the job to the submission queue, with the same job ID. LSF dispatches the job as if it was a new submission, even if the job has been checkpointed.