Patent ID: 7840133

Claim:
A method of carrying out protection of data traffic in a multi-channel multi-section ring-like optical communications network by simultaneously using Optical Multiplexed Section (OMS) protection and Optical Channel (OCH) protection, the method comprising: providing the OMS protection for at least one section of the network by ensuring, in case of a failure in said section, switching of the data traffic from one of said configurations to another of said configurations at each of two ends of said section; providing the OCH protection for at least one optical channel in the network, by transmitting data related to said optical channel from one of said network elements being a source point of said channel to another of said network elements being a destination point of said channel by means of two optical signals, wherein one of said optical signals is transmitted via the main configuration and another of said optical signals is transmitted via the protecting configuration; preliminarily applying a specific additional pilot tone for transmitting data from the source point of the OCH protected channel via a specific one of said configurations, selecting an optical signal in an OCH protected optical channel, in case of a fault in a section of said network, by relying on an indication associated with OMS switching functionality required to overcome said fault, wherein said step of selecting being performed by rejecting the one of the two optical signals of said OCH protected channel, that has undergone the switching from one of said configurations to another of said configurations owing to the OMS protection, the rejecting being based on detecting a discrepancy, from the point of presence of said specific pilot tone, between a received and an expected optical signal from one of said configurations at the destination point of said OCH protected channel, the discrepancy serving said indication, wherein the communication network consisting of no more than two ring-like configurations respectively formed by no more than two optical fibers connecting network elements, one of said configurations is considered a main configuration and the other is considered a protecting configuration, and wherein said specific optical signal in said OCH protected optical channel is selected between one signal transmitted via the main configuration and another signal transmitted via the protecting configuration.