If I start a full backup from a client (SSMS) in China, but both server and backup location are in the US, does all network traffic stay within the US, or does it have to transverse over to the client machine and back?

If I start a full backup from a client (SSMS) in China, but both server and backup location are in the US, does all network traffic stay within the US, or does it have to transverse over to the client machine and back? I imagine the answer is obviously the traffic is only between the server and the backup location. But not always things are programmed in obvious ways. So, anyone?

TIA,

Raphael

rferreira