Application of hardware-based mailboxes in network transceivers and distributed approach for predictable software-based protection switching

A network node comprising:

• a client interface that receives a client signal carrying data at a first rate;
• first and second line modules, the first line module being configured to supply a first plurality of optical signals, each having a corresponding one of a first plurality of wavelengths, to a first path, each of the first plurality of optical signals carrying information corresponding to one of a plurality of portions of the data, each of the first plurality of optical signals carrying the information at a second rate less than the first rate, the second line module being configured to supply a second plurality of optical signals, each having a corresponding one of a second plurality of wavelengths, to a second path, each of the second plurality of optical signals carrying the information corresponding to said one of the plurality of portions of the data, each of the second plurality of optical signals carrying the information at the second rate, the first plurality of wavelengths being different than the second plurality of wavelengths;
• first and second CPUs provided in the first and second line modules, respectively, the first CPU being configured to change a state of the first path from a protection state to a working state;
• first and second memories included in the first line module, and first and second memories provided in the second line module;
• and
• a communication bus coupled to the first and second memories in the first line module and the first and second memories in the second line module, such that first state information associated with the first path is stored in the first memory in the first line module and supplied over the communication bus to the first memory in the second line module, and second state information associated with the second path is stored in the second memory in the second line module and supplied over the communication path to the second memory in the first line module, wherein the first state information indicates that the first path is a working path, the first and second memories further store a common identifier associated with the first and second plurality of optical signals, such that, in response to a fault in the first path and based on the common identifier, the first and second CPUs cooperate to deactivate transmission of the first plurality of optical signals on the first path activate transmission of the second plurality of optical signals on the second path.