Subsystem Failure   is generated when a signaling point is faulty or a subsystem of the signaling point is faulty.

it can impact following way;

• The subsystem of the SCCP layer at the peer end is faulty.
• The DSP is inaccessible.

1. Run LST SCCPSSN to query the subsystem index based on the DSP index and subsystem number contained in the alarm and then run DSP MULSSN to check whether the subsystem reported in the alarm is faulty.
2. Run DSP MULN7DSP to check whether the DSP is accessible based on the DSP index contained in the alarm.
3. Run LST N7DSP to query the DPC based on the DSP index contained in the alarm and then run LST M3AS to check whether the AS index exists based on the DPC.
4. Run DSP MULM3AS to check whether the AS is accessible.
5. Check whether there is a remote SCCP failure alarm.

on the aspect of situation it will assist a lot