ATM-Dienstunterbrechungsmessung

摘要

A data analyzer system (60) is used to measure the duration of a service disruption event in an asynchronous transfer mode (ATM) data transmission channel (67) carrying an ATM stream of identifiable data cells in a defined order. The data analyzer system (60) comprises error detection means (70) for determining whether or not any of the data cells have been corrupted in transmission through the data transmission channel when the transmission is disrupted, and a disruption timer (73) for timing the service disruption event starting when a first corrupted data cell is detected by the error detection means (70). The data analyzer system has a guard timer (74) for timing a guard time interval when uncorrupted data cells are detected by the error detection means (70), and control means (71) for controlling the operation of the disruption timer (73) and guard timer (74) in response to the determination by the error detection means (70) of whether or not any data cells have been corrupted. The disruption timer (73) is operable to time a service disruption event from the start of the disruption event until the guard timer (74) has timed a predetermined guard time, and the guard timer (74) is operable to time the guard time interval when corrupted data cells are followed by a resumption of uncorrupted data cells.