You can also check this file. It is for NBU6.0 , but I do not think that 7.x has many changes
http://uploading.com/files/5af72bb8/Details%2Bon%2Bthe%2BVERITAS%2BNetBackup%2B%2528tm%2529%2B6.0%2BBackup%2Band%2BRestore%2BProcess%2BFlow.pdf
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu [mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Michael Graff Andersen
Sent: Friday, November 26, 2010 2:47 PM
To: Saran Brar
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Netbackup Daemon flow info
There used to be some drawings of the backup & restore proces flow in the back of the troubleshooting guide