Excessive traffic between VDP and vCenter Server

Good day to every one,

I have a matter that i hope some one could shine some light on.

I found some traffic between vDP and VC that could total to 2GB in a day.

vsphere enviroment - 5.5 upgraded from 5.1

One VC, One vDP

VC managing the rest(ESX/VMs/vDP) over and 512mb cross-site wan line.

I understand that vDP doesn't go thru VC to perform backup; maybe sends logs and some basic configs to VC. So, whats all that traffic going on btw VC and vDP? even if the enviroment is much larger, the bottle-neck should still be on vDP-ESX-storage.

As you noticed that the WAN line is small, in this case, 2GB in a day over WAN is a concern.

Thank you