System/Node resolver

System/Node resolver, also called Propagation Manager, helps to connect shapes from different SAS subsystems or nodes correctly.
It launches automatically every time shapes are connected and compares subsystems (P, E, etc.) and nodes assigned to the shapes.

If one of the shapes/signals has no SAS subsystem defined, System/Node resolver automatically assigns the same SAS subsystem as the other connected shape has.

In case if both connected shapes/signals have different SAS subsystems, System/Node resolver warns user about the case and suggests to either choose one of the subsystems or create interface signal between the shapes.

Interface signal is used to connect shapes with different SAS subsystems and/or nodes.
Interface signals have their own I subsystem in the SCD ToolBox. They are displayed green on the diagrams.