I wanted to restrict the backup to be started or restarted in the backup time 
window defined in NetBackup policy. When it is out of the time window, the 
startup/restart is not allowed.

to achieve that, I am thinking if there is NetBackup parameter feeding in 
bpstart_notify script, and thus we can add a logic in the script to see if the 
time is out of the backup window or not, if it is, then exit from the script.

Please advice. Thanks,
J.