fault management (FM)

Fault management (FM) is a functional area of OSI management and fault, configuration, account, performance, and security management( FCAPS) and includes all tasks for fault prevention, fault detection, and fault elimination. By constantly monitoring the network and the connected systems, changes in the network parameters are detected and conclusions drawn about expected faults.

The main fault management tasks are status indication, fault detection, fault correction, alarm triggering and problem analysis, and fault recovery procedures.

The fault detection and fault correction are qualified and quantified by the fault rate and fault duration. The evaluation is done by the different mean time to repair and failure:

• Mean Time between Failure and Repair (MTFR) is the average time from the occurrence of a failure to its correction.
• Mean Time between Failure and Disclosure (MTFD) is the average time from the occurrence of a failure to its discovery.
• Mean Time between Disclosure and Diagnosis (MTDD) is the average time between the discovery and diagnosis of a failure.
• Mean Time between Diagnosis and Repair (MTDR) is the average time between diagnosis and repair of a fault.
• Mean Time between Failures( MTBF) is the average time between the occurrence of two failures.