Method for detecting and locating a break in a synchronous digital hierarchy (SDH) optical link system

摘要

A method for detecting a break occurred in an optical link system and quickly and accurately locating the position of such a break. The present invention provides for the use of an alarm indication signal (AIS) of the SDH regeneration section in a non compliant interface of the optical transport network. The basic idea consists in extending the application of the Alarm Indication Signal to the regeneration section of the SDH link layer. With the introduction of the Optical Layer, as lower layer in the Transport network, the event of the break in a cable as a fault condition in the Regeneration Section of an SDH network is replaced by the cable break event in the transmission section of an optical network. The tributary of the WDM terminal will construct an SDH-compliant Alarm Indication Signal as a result of the break in a fiber or of the reception of a lower or server layer fault signal. As a result, the SDH network manager will not be led in error as to the fault location.