Method and Apparatus for Scheduling Communication using a Star Switching Fabric

Abstract

In one embodiment, a scheduler for use with a star switching fabric includes a scheduling star switching fabric operable to receive a plurality of packets each associated with one of a plurality of wavelengths and a plurality of selecting elements associated with the scheduling star switching fabric. Each of the plurality of selecting elements is operable to contribute to selectively passing packets from the scheduling star switching fabric for receipt by a transmission star switching fabric. Packets received at the transmission star switching fabric over a given time period comprise a more uniform load distribution than packets received at an input to the scheduler over the same period of time.

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       8 . A network operable to direct optical signals, the network comprising: 
 a scheduler engine operable to generate one or more control signals;    one or more control lasers coupled to the scheduler engine, each of the one or more control lasers operable to generate an optical control signal based at least in part on a portion of the one or more control signals, wherein the optical control signal comprises at least a portion of information of the one or more control signals;    a transmission star fabric coupled to the one or more control lasers, the transmission star fabric operable to distribute the optical control signal to a first plurality of line cards, each of the first plurality of line cards comprising one or more receivers coupled to an electronic processor and further coupled to one or more transmitters, the one or more receivers adapted to receive the optical control signal, the one or more optical transmitters adapted to communicate one or more optical output signals to the transmission star fabric, wherein the one or more optical output signals are communicated based at least in part on the portion of information of the one or more control signals, and wherein the optical control signal is at a different optical wavelength than at least some of the one or more optical output signals;    wherein the transmission star fabric is operable to combine at least some of the optical output signals into one or more combined optical output signals and to direct at least a portion of the one or more combined output signals to an input buffer;    wherein the one or more control signals generated by the scheduler engine control firing of the one or more transmitters using a scheduling algorithm that operates to avoid collisions between the optical output signals in the transmission star fabric;    wherein the scheduler engine is further coupled to an optical switching fabric that communicates at least some of the information of the at least a portion of the one or more combined output signals with a second plurality of line cards; and    wherein traffic transmitted through the transmission star fabric comprise at least in part an Internet Protocol (IP) or a Transmission Control Protocol (TCP) packet.    
   
   
       9 . The network of  claim 8 , wherein the one or more optical output signals comprise variable length packets, each of the variable length packets comprising a header and a variable length payload.  
   
   
       10 . The network of  claim 8 , wherein the input buffer is further coupled to a wavelength division multiplexer capable of combining different wavelength signals into a common path, and wherein the wavelength division multiplexer is further coupled to an optical amplifier adapted to at least partially compensate for loss associated with the transmission star fabric.  
   
   
       11 . The network of  claim 8 , wherein the optical switching fabric is further coupled to one or more tunable lasers.  
   
   
       12 . The network of  claim 8 , wherein the optical switching fabric comprises one or more optical devices selected from a group consisting of micro-electromechanical switches (MEMS) and liquid crystal devices.  
   
   
       13 . The network of  claim 8 , wherein traffic through the optical switching fabric comprises one or more express channels that bypass optical-to-electrical conversion at a location associated with the optical switching fabric.  
   
   
       14 . The network of  claim 8 , wherein traffic transmitted through the optical switching fabric comprise at least in part Multi-Protocol Label Switching (MPLS) or Generalized Multi-Protocol Label Switching (GMPLS) packets.  
   
   
       15 . A method of directing optical signals, the method comprising: 
 generating, at a scheduler engine, one or more control signals;    converting at least a portion of the one or more control signals into an optical control signal;    distributing the optical control signal using a transmission star fabric to a first plurality of line cards, each of the first plurality of line cards comprising one or more receivers coupled to an electronic processor and further coupled to one or more optical transmitters;    receiving, at the one or more receivers, the optical control signal;    communicating, from the one or more optical transmitters, one or more optical output signals to the transmission star fabric, wherein the one or more optical output signals are communicated based at least in part on a portion of information of the one or more control signals, and wherein the optical control signal is at a different optical wavelength than at least some of the one or more optical output signals;    combining, in the transmission star, at least some of the optical output signal into one or more combined optical output signals; and    receiving, at the scheduler engine, at least some information of the one or more combined output signals;    communicating at least some of the information from the combined output signals from the scheduler engine to a second plurality of line cards through an optical switching fabric;    producing a more uniform traffic distribution at one or more outputs from the optical switching fabric compared with one or more inputs to the optical switching fabric;    wherein the one or more control signals generated by the scheduler engine control firing of the one or more transmitters using a scheduling algorithm that operates to avoid collisions between the optical output signals in the transmission star fabric.    
   
   
       16 . The method of  claim 15 , wherein the one or more optical output signals comprise variable length packets, each of the variable length packets comprising a header and a variable length payload.  
   
   
       17 . The method of  claim 15 , wherein the transmission star fabric is further coupled to an optical amplifier operable to at least partially compensate for loss associated with the transmission star fabric.  
   
   
       18 . The method of  claim 15 , wherein traffic through the optical switching fabric comprises one or more express channels that bypass optical-to-electrical conversion at a location associated with the optical switching fabric.  
   
   
       19 . The method of  claim 15 , wherein the optical switching fabric comprises one or more optical devices selected from a group consisting of micro-electromechanical switches (MEMS) and liquid crystal devices.  
   
   
       20 . The method of  claim 15 , wherein the transmission star fabric is further coupled to an Ethernet network.  
   
   
       21 . The method of  claim 15 , wherein traffic transmitted through the optical switching fabric comprise at least in part an Internet Protocol (IP) packet, a Transmission Control Protocol (TCP) packet, a Multi-Protocol Label Switching (MPLS) packet, or a Generalized Multi-Protocol Label Switching (GMPLS) packet.  
   
   
       22 . A network operable to direct optical signals, the network comprising: 
 a scheduler engine operable to generate one or more control signals;    one or more control lasers coupled to the scheduler engine, each of the one or more control lasers operable to generate an optical control signal based at least in part on a portion of the one or more control signals, wherein the optical control signal comprises at least a portion of information of the one or more control signals;    a transmission star fabric coupled to the one or more control lasers, the transmission star fabric operable to distribute the optical control signal to a first plurality of line cards, each of the first plurality of line cards comprising one or more receivers coupled to an electronic processor and further coupled to one or more optical transmitters, the one or more receivers adapted to receive the optical control signal, the one or more optical transmitters adapted to communicate one or more optical output signals to the transmission star fabric, the one or more optical output signals communicated based at least in part on the portion of information of the one or more control signals, wherein the optical control signal is at different optical wavelengths than at least some of the one or more optical output signals;    wherein the one or more optical output signals comprise variable length packets, each of the variable length packets comprising a header and a variable length payload;    wherein the transmission star fabric is operable to combine at least some of the optical output signals into one or more combined optical output signals and to direct at least a portion of the one or more combined output signals to an input buffer;    wherein the one or more control signals generated by the scheduler engine control firing of the one or more transmitters using a scheduling algorithm that operates to avoid collisions between the optical output signals in the transmission star fabric;    wherein the scheduler engine is further coupled to an optical switching fabric, wherein the scheduler engine is operable to receive at least some of the information of the one or more combined output signals and to communicate at least some of the information of the one or more combined output signals to a second plurality of line cards through the optical switching fabric; and    wherein the optical switching fabric comprises one or more optical devices selected from a group consisting of micro-electromechanical switches (MEMS) and liquid crystal devices.    
   
   
       23 . The network of  claim 22 , wherein traffic transmitted through the optical switching fabric comprise at least in part Multi-Protocol Label Switching (MPLS) or Generalized Multi-Protocol Label Switching (GMPLS) packets.  
   
   
       24 . The network of  claim 23 , wherein traffic through the optical switching fabric comprises one or more express channels that bypass optical-to-electrical conversion at a location associated with the optical switching fabric.  
   
   
       25 . The network of  claim 24 , wherein the optical switching fabric is further coupled to one or more tunable lasers.  
   
   
       26 . The network of  claim 24 , wherein the input buffer is further coupled to a wavelength division multiplexer capable of combining different wavelength signals into a common path, and wherein the wavelength division multiplexer is further coupled to an optical amplifier adapted to at least partially compensate for loss associated with the transmission star fabric.  
   
   
       27 . The network of  claim 24 , wherein the transmission star fabric is further coupled to an Ethernet network.