Connection calculation in a topology

In my opinion, not really.

For a Network diagram, I would call the connection between two objects a "link" - the point-to-point transport over which network data can flow.

A connection is a tcp connection between two devices established on

source ip:source port -> destination ip:destination port

Connections may traverse a number of links and intervening devices (bridges/routers/switches/etc)

I hope this is clear.