KNX - Multiple KNX/IP Routers/Interfaces necessary?

Hi all,

my current KNX architecture looks like this:

  • Line 1.1 - First floor
  • Line 1.2 - Second floor
  • Line 1.2.1 - KNX/IP Interface

Lines 1.1 and 1.2 are not connected and I can only control line 1.2 via the one KNX/IP Interface I currently have. This is what I want to change.

Furthermore I’d like to add a weather station, which needs to be connected to both floors. As far as I’ve figured things out, one typically adds something like a weather station to line 1.0, so that the architecture would look like this:

  • 1.0.1 Weather station
  • 1.1.0 TP/Line coupler
  • 1.2.0 TP/Line coupler
  • 1.2.1 KNX/IP Interface

Then when programming via ETS it would automatically adjust the filters in the couplers to allow telegrams regarding the connections (via group addresses) with the weather station through.

But that still doesn’t allow me to control line 1.1 with OpenHAB.

From what I could find in this forum, I could use KNX/IP Routers instead of the TP/Line couplers. However, that would mean I don’t have a line 1.0, to which I could attach the weather station. Does this mean I would need three KNX/IP Routers and the following architecture?

  • Line 1.0.0 KNX/IP Router
  • Line 1.0.1 Weather station
  • Line 1.1.0 KNX/IP Router
  • Line 1.2.0 KNX/IP Router

Now everything would be connected via KNX/IP multicast.

But, how does attaching OpenHAB in KNX Bridge mode work? Would I need to set the filter tables of all three KNX/IP Routers to allow all telegrams to pass through, so that OpenHAB could send telegrams to all three lines and also receive feedback from all three?

What I want to prevent is that telegrams of line 1.1 end up in line 1.2 and vice versa. Would I need to configure the OpenHAB KNX binding to use the KNX/IP Routers as interfaces instead, if I want to avoid that?

Is there a better way to achieve my goals? Could I somehow use the KNX/IP Interface I have for multiple lines and connect the rest with TP/Line couplers, or are separate KNX/IP interfaces per line necessary, if I want the filters in the couplers to be active?

Thanks in advance!