Debugging Remote Function Modules 

For testing "ABAP-to-ABAP" RFCs, you can use the ABAP Debugger. Here, you can debug the RFC function call in the remote system. Static breakpoints, single-stepping, variable-watching and source display are possible.

With remote calls, the ABAP debugger (including the debugging interface) runs on the local system. Data values and other run information for the remote function are passed in from the remote system.