I just want to answer your connections and session comparison,
A connection is opening a communication between a client to a requested node.
In lay mans term, a pc (1)connects to a (1)server that is 1 connection. (can be close and open)
A session is an opening of actions to a certain applications or systems,
Again, 1 user can make multiple sessions. on the server side, it could accumulate to your server and occupy resources.
Sessions wont end unless it has a time limit or terminated.
I think you should limit or make the time span shorter for taking care of idle sessions.