1. Place the mouse cursor on the port you want to interconnect.
2. Click with the left mouse button and hold it down.
3. Move the mouse pointer.

The pointer now shows the networking symbol to indicate "Interconnect" mode. At the same time, the mouse pointer shows the lock symbol that will only disappear when the pointer is on a valid target.

4. Now drag the mouse cursor to the target port. You can do this while holding down or after releasing the mouse button.
5. Now release the left mouse button or press it again (depending on your previous action).

Creating a ring for S7-300, S7-400, and S7-1500 CPUs

If you create a ring using port interconnections for S7-300, S7-400, or S7-1500 CPUs, an MRP domain is created automatically.