SLP from VTL to VTL - Optimize Duplication?

Hi,

I have a question regarding SLP and optimize duplication.I have 2 VTL's located in 2 different location under the same NetBackup domain. The VTL is actually create on a HP StoreOnce device which has deduplication & replication capability. In this case when SLP is triggered, the duplication traffic will it be via the media servers? Or it will be only between the 2 VTL?

In what scenario where Optimize Duplication be possible in my case?

Regards,

Jeffrey