Uploading files from desktop to remote FTP, using ES File Explorer to initiate and the related traffic?

At home have an older Windows desktop with a TB of hard drive and I constantly send files to it over my home network from my Note 4 and have amassed quite the collection. This morning, I started to upload a lot of it to a remote FTP server using ES File Explorer on my Note 4. I can click on my Windows desktop then select a group of files, copy and paste them to the FTP server and I get a progress bar of the transfer from "smb://desktop/users/" to "ftp://ftp.myserver.net/" and my question is if the data literally moves like that? The Windows machine is connected to the cable modem on an Ethernet wire and my Note 4 is on the crowded wireless network.