Procedures, apparatuses, systems, and computer programs for providing optical network channel protection

Abstract

A procedure for transferring wavelengths, and a system that operates in accordance with the procedure. The system comprises at least one network terminal, each including a switch and a controller. A plurality of wavelength sets are applied to the switch. The controller is arranged to operate the switch such that the switch (a) selects at least one wavelength from at least one of the plurality of wavelength sets, based on electrical monitoring at a port module external to the network terminal, and (b) outputs the at least one wavelength to an output of the at least one network terminal.

1 - 20 . (canceled) 
     
     
         22 . A system comprising:
 add-drop multiplexers;   port modules; and   at least one network terminal, each network terminal having a first path through which at least one wavelength can be communicated between a first one of the add-drop multiplexers and a first one of the port modules, and also having a second path through which the at least one wavelength can be communicated between a second one of the add-drop multiplexers and a second one of the port modules,   wherein at least one of a group including the at least one network terminal, the first add-drop multiplexer, and the second add-drop multiplexer is arranged to select one of the first or second paths as a working or protect path based on a detection in an electrical domain.   
     
     
         23 . The system of  claim 22 , wherein the system provides 1:n protection. 
     
     
         24 . The system of  claim 22 , wherein the at least one network terminal further has a third path through which at least one other wavelength can be communicated between a third one of the add-drop multiplexers and the first one of the port modules, and also having a fourth path through which the at least one other wavelength can be communicated between a fourth one of the add-drop multiplexers and the second one of the port modules,
 wherein at least one of a further group including the at least one network terminal, the third add-drop multiplexer, and the fourth add-drop multiplexer, is arranged to select one of the third or fourth paths as a working or protect path based on a corresponding detection in an electrical domain.   
     
     
         25 . The system of  claim 24 , wherein the system provides 1+n protection. 
     
     
         26 . The system of  claim 22 , wherein the at least one network terminal includes two network terminals. 
     
     
         27 . The system of  claim 24 , wherein the at least one network terminal includes at least three network terminals. 
     
     
         28 . The system of  claim 22 , wherein the at least one network terminal comprises a switch arranged to select the one of the first or second paths as the working or protect path based on the detection in the electrical domain. 
     
     
         29 . The system of  claim 22 , wherein the at least one network terminal comprises a splitter, and wherein the first and second paths traverse the splitter. 
     
     
         30 . The system of  claim 28 , further comprising a splitter, a third path through which at least one wavelength can be communicated between the first add-drop multiplexer and the first port module by way of the splitter, and a fourth path through which the at least one wavelength can be communicated between the second add-drop multiplexer and the second port module by way of the splitter. 
     
     
         31 . The system of  claim 30 , wherein the at least one wavelength of the first path is the same at the at least one wavelength of the third path, and the at least one wavelength of the second path is the same as the at least one wavelength of the fourth path. 
     
     
         32 . The system of  claim 22 , wherein the at least one wavelength includes a plurality of wavelengths. 
     
     
         33 . The system of  claim 22 , wherein each add-drop multiplexer is a reconfigurable add-drop multiplexer (ROADM). 
     
     
         34 . A method for forwarding communications, comprising:
 communicating at least one wavelength along a first path in at least one network terminal interposed between a first add-drop multiplexer and a first port module;   communicating at least one wavelength along a second path in the at least one network terminal interposed between a second add-drop multiplexer and a second port module; and   selecting, by at least one of a group including the at least one network terminal, the first add-drop multiplexer, and the second add-drop multiplexer, one of the first or second paths as a working or protect path, based on a detection in an electrical domain.   
     
     
         35 . The method of  claim 34 , further comprising at least one of the first and second port modules performing the detection in the electrical domain. 
     
     
         36 . The method of  claim 34 , further comprising:
 communicating at least one other wavelength along a third path in the at least one network terminal interposed between a third add-drop multiplexer and a third port module;   communicating at least one other wavelength along a fourth path in the at least one network terminal interposed between a fourth add-drop multiplexer and a fourth port module; and   selecting, by at least one other group including the at least one network terminal, the third add-drop multiplexer, and the third add-drop multiplexer, one of the third or fourth paths as a working or protect path, based on a corresponding detection in an electrical domain.   
     
     
         37 . The method of  claim 36 , wherein the at least one wavelength of the first path is the same at the at least one wavelength of the third path, and the at least one wavelength of the second path is the same as the at least one wavelength of the fourth path. 
     
     
         38 . The method of  claim 34 , wherein each add-drop multiplexer is a reconfigurable add-drop multiplexer (ROADM). 
     
     
         39 . The method of  claim 34 , wherein a splitter is included in the first path, and a switch is included in the second path. 
     
     
         40 . The method of  claim 39 , wherein a multiplexer is included in the first path, and a demultiplexer is included in the second path. 
     
     
         41 . A computer-readable medium storing instructions which, when executed by a computer processor, cause the computer processor to perform a method for forwarding communications, the method comprising:
 communicating at least one wavelength along a first path in at least one network terminal interposed between a first add-drop multiplexer and a first port module;   communicating at least one wavelength along a second path in the at least one network terminal interposed between a second add-drop multiplexer and a second port module; and   selecting, by at least one of a group including the at least one network terminal, the first add-drop multiplexer, and the second add-drop multiplexer, one of the first or second paths as a working or protect path, based on a detection in an electrical domain.