IPx/S 3.1.1: Which tunnel connection is visibly displayed in the Connection Manager in the ETS?
The lowest and freely available physical address of a tunnel is always shown. Occupied tunnel connections are not displayed.
Also see: http://new.abb.com/low-voltage/products/intelligent-building-systems/abb-i-bus-knx/new-abb-i-bus-knx-ip-devices