What does a Gateway Session ID represent in BusinessConnect Log Viewer -> Gateway Management -> Gateway Service Session log entries?

[Dave Bauer]

I have a partner sending 50 files to our SFTP server. The BusinessConnect Gateway Service Session has 50 entries, and each entry contains the Log On and Log Out activities with unique Transaction IDs. However, each of those entries in the Gateway Service Session has the same Gateway Session ID. If one Gateway Session ID is logged for all 50 transactions, what does the Gateway Session ID represent? I'm trying to ascertain if the client is logging on to the SFTP server for each individual file it sends (50 logins), or once and sending all 50 files in one session (one login).