[vRA8 - ICM]:- vRA w/ NSX-t External Network confusion

[SrVMwarer]

Hello Cloud builders! 

I am getting my hands-on w/ vRA-8 integrating it with NSX-T 

In the below screenshot I am confused why I am specifying an External Network [DVS port group]

While the deployed VMs doesn't seem to be consuming it, rather its consuming the N-VDS 

[frippeisking]

I think locally on the ESX host that it's running on it would be a N-VDS but on the edge reaching outside/externally to vRA/NSX (on the edge node) it will use that portgroup. My understanding at least.