The prompt recovery of facility is wanted at the time of a failure occurrence in the maintenance operation of optical transmission networks. However, it is estimated that the period to evaluate a failure may be elongated in the case in which it is difficult to evaluate a failure based on the checking of alarm-monitoring and/or device logs. For the solution of this, we have been studying the failure evaluating technology to use a variety of performance information on the optical signals gained from optical transmission devices. This technology analyzes the performance information on the optical signals including the influence from failures occurring on transmission paths and identifies the location/cause of the occurrence of such failures.
Optical cross connections and optical amplifiers are connected in multiple phases for the long-distance transmission in multiple directions on networks of core optical transmission. The device such as these is not equipped with detailed monitoring functions concerning the conditions of optical signals; there may be a case in which a failure is detected only on the reception terminal on an optical path (a module to send and receive client signals) concerning a failure having occurred in the middle of a transmission path. In a case like this, where the quality degradation of optical signals has occurred is not known from device logs; there may be a case in which it is not possible to identify the location or the cause of such failure occurrence.
NTT Network Service Systems Laboratories - ·Transport Network Innovation Project