Architecture of a bidirectional wavelength path switched ring and its implementation schemes

A bidirectional wavelength path switched ring is proposed to provide 1:1 system protection for digital client layer such as a SONET system. This WDM ring has advantages in both the required number of wavelengths and optical signal-to-noise ratio. A distributed control scheme is suggested to implement this ring architecture. This scheme requires no signaling between nodes for indicating failure and works fast enough to satisfy the higher layered SONET system's switching requirement.