Shakil,
As far as I know the licensing process for Net Backup is one is to one meaning 1 license is to 1 server. (Just like BACKUP EXEC) Same thing applies with agents and options, you have to purchase separate license per agent or option you wish to use or activate unless a specific option is bundled with an agent then you have to use the same key.
The following Agents and options are purchased separately
Veritas NetBackup Deployment
Veritas NetBackup for Enterprise Vault Enterprise Vault
Veritas NetBackup Vault Veritas NetBackup Vault
Veritas NetBackup for DB2 Veritas NetBackup for DB2
Veritas NetBackup for Informix
Veritas NetBackup for Lotus Notes
Veritas NetBackup for Microsoft Active Directory
Veritas NetBackup for Microsoft SQL Server Veritas
Veritas NetBackup for Microsoft Office SharePoint
Veritas NetBackup for NDMP Veritas
Veritas NetBackup for Oracle Veritas
Veritas NetBackup for SAP Veritas
Veritas NetBackup for Sybase
OptionsVeritas NetBackup Bare Metal Restore
Veritas NetBackup Desktop and Laptop Option
Veritas NetBackup Encryption Options Physical
NetBackup Media Server Encryption Option
Veritas NetBackup Flexible Disk Option
Veritas NetBackup for Microsoft Hyper-V
Veritas NetBackup Open Storage Option
Veritas NetBackup Shared Storage Option
Veritas NetBackup for VMware
For Licensing assistance or query, login a case on https://mysupport.symantec.com/
or send an email to customercare_emean@symantec.com
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hope that helps..