Mike -
The difference in NDMP design shouldn't matter with the control path.
I don't think It should matter whather it's direct, indirect, or three way architecture.
The only thing that changes is the data connection not the control connection ...
I hope this response has been helpful to you.
At your service,
Eugene E. Kashpureff, Sr.
Independent NetApp Consultant http://www.linkedin.com/in/eugenekashpureff
Senior NetApp Instructor, Fast Lane US http://www.fastlaneus.com/
(P.S. I appreciate 'kudos' on any helpful posts.)