Method and apparatus for minimizing data loss with protection switching in optical transport network system

Provided are linear automatic protection switching (APS) apparatus and method which minimize a data loss in an optical transport network (OTN) system. The apparatus and method may maintain time synchronization by transmitting/receiving time synchronization signals between APS apparatuses in a working path and a redundant path, and transmitting/receiving time synchronization signals between local and remote APS apparatuses. The present invention aims to execute switching at the same time by transmitting/receiving switching execution times generated by the APS apparatuses and thus to minimize a data loss caused by protection switching. Also, the present invention aims to provide precise time synchronization by recording the time synchronization signals or the switching execution times in an APS frame or an ODU frame.