In-service monitoring methods-better ways to assure service quality of digital transmission

This paper focuses on how transmission error performance can be evaluated by parameters such as errored seconds (ES) and severely errored seconds (SES), under in-service conditions. Currently, attention is being paid to In-Service Monitoring (ISM) as an effective measurement technique for the error performance in digital networks. So the paper, first of all, overviews error performance parameters and shows the concept of ISM. It next discusses estimation methods for the error performance of digital channels by using information on anomaly and defect events in transmission systems. Furthermore, the paper refers to the potential usage of ISM for service quality estimation and performance assurance