Optical switch and protocols for use therewith

Abstract

A method of establishing a data connection between terminal switching nodes in a network and switching nodes for implementing the method. The method involves switching nodes participating in a network layer wavelength routing (WR) protocol to determine the next hop switching node for every possible combination of terminal nodes based on the network topology. The method also involves the switching nodes participating in a network layer wavelength distribution (WD) once the data connection is to be established. The WR protocol determines the path used through the network, while the WD protocol assigns wavelengths on each link between switching nodes. The wavelengths may be different on different optical links. The switching nodes include wavelength converters with an optical switch or optoelectronic converters with a digital electronic switch. A digital electronic switch can also provide signal reformatting. Advantages of using potentially different wavelengths along various segments of a single end-to-end connection yields increased wavelength efficiency.

1 .- 29 . (canceled) 
     
     
         30 . A method for switching optical signals at an apparatus, the apparatus comprising a plurality of input ports for receiving optical signals at various input wavelengths and a plurality of output ports for outputting optical signals at various output wavelengths, the method comprising:
 maintaining association data that associates combinations of the input ports and input wavelengths to respective combinations of the output ports and output wavelengths;   switching the signals received via the input ports to corresponding ones of the output ports in accordance with the association data;   outputting the switched signals via the output ports at corresponding wavelengths in accordance with the association data.   
     
     
         31 . The method defined in  claim 30 , wherein outputting the switched signals via the output ports at corresponding wavelengths in accordance with the association data comprises:
 selectively changing the wavelengths of the signals received via the input ports in accordance with the association data.   
     
     
         32 . The method defined in  claim 31 , wherein selectively changing the wavelengths of the signals received via the input ports comprises:
 changing the wavelength of a signal characterized by a particular combination of input wavelength and input port if said input wavelength differs from the output wavelength in the associated combination of output wavelength and output port.   
     
     
         33 . The method defined in  claim 30 , further comprising changing the association data in accordance with operation of a routing protocol. 
     
     
         34 . An apparatus for switching optical signals, the apparatus comprising:
 a plurality of input ports for receiving optical signals at various input wavelengths;   a plurality of output ports for outputting optical signals at various output wavelengths;   a memory for storing information that associates combinations of the input ports and input wavelengths to respective combinations of the output ports and output wavelengths;   switching means capable of switching the signals received via the input ports to corresponding ones of the output ports in accordance with the information stored in the memory; and   means for causing the signals output via the output ports to occupy corresponding wavelengths in accordance with the information stored in the memory.   
     
     
         35 . The apparatus defined in  claim 34 , wherein the switching means is operative to perform all-optical switching. 
     
     
         36 . The apparatus defined in  claim 35 , wherein the means for causing comprises wavelength conversion circuitry operative to perform wavelength conversion on the signals received via the input ports in accordance with the information stored in the memory. 
     
     
         37 . The apparatus defined in  claim 36 , wherein the wavelength conversion circuitry is connected to the switching means such that the wavelength conversion is performed prior to the switching. 
     
     
         38 . The apparatus defined in  claim 36 , wherein the wavelength conversion circuitry is connected to the switching means such that the wavelength conversion is performed subsequent to the switching. 
     
     
         39 . The apparatus defined in  claim 34 , further comprising opto-electronic conversion circuitry coupled to the input ports, for converting the optical signals received via the input ports into a set of first electrical signals, wherein the switching means is operative to perform electrical switching of the set of first electrical signals over to a set of switched electrical signals. 
     
     
         40 . The apparatus defined in  claim 39 , wherein the means for causing comprises electro-optical conversion circuitry coupled between the switching means and the output ports, the electro-optical conversion circuitry being operative to convert the switched electrical signals into the optical signals output via the output ports. 
     
     
         41 . The apparatus defined in  claim 40 , further comprising a controller coupled to the memory and to the electro-optical conversion circuitry, wherein the controller is operative to indicate to the electro-optical conversion circuitry the wavelengths on which to output the optical signals output via the output ports. 
     
     
         42 . The apparatus defined in  claim 41 , wherein the set of first electrical signals are associated with respective signaling types, wherein the switching means is operable to change the signaling types associated with the set of first electrical signals.