On the target platform, launch the application with GDBserver, while specifying the host and port for listening to an incoming TCP connection:
gdbserver HOST:PORT PROG [ARGS ...]
gdbserver 10.19.103.55:123 test_rsh_sw.bin r
On the development workstation, launch the cross-target GDB:
Be sure to specify the non-stripped executable. At the GDB console, type:
target remote HOST:PORT
These commands will connect GDB to the GDBserver running on the target platform, set a breakpoint at the start of the program, and let it run until it reaches that first breakpoint.
You can also attach GDBserver to a process that's already running:
gdbserver HOST:PORT --attach PID
The process is then stopped, and you can then debug it with a remote GDB.