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 . An intermediate switching node configured to establish an optical connection between a first terminal switching node and a second terminal switching node via one or more intermediate switching nodes along a path in an optical network, the intermediate switching node being configured to:
 receive a communication from an adjacent switching node along the path;   if the communication is a connection request communication, then:
 identify a communication channel identifier for a communication channel that is available on a link between the current switching node and the previous switching node; and 
 forward the connection request communication to the next switching node along the path; and 
   if the communication is a connection confirm communication, then:
 establish a connection to the previous switching node along the path using the previously identified available communication channel; and 
 send a connection confirm communication to the previous switching node along the path. 
   
     
     
         31 . The intermediate switching node of  claim 30 , wherein each connection request communication comprises a connection request message. 
     
     
         32 . The intermediate switching node of  claim 30 , wherein each connection confirm communication comprises a connection confirm message. 
     
     
         33 . The intermediate switching node of  claim 30 , wherein the intermediate switching node is configured to:
 store a routing table identifying a next hop switching node for the path; and   store a communication channel availability table identifying any communication channels not yet allocated to connections.   
     
     
         34 . The intermediate switching node of  claim 33 , wherein the routing table identifies a respective next hop switching node for a respective path between each possible pair of first and second terminal switching nodes. 
     
     
         35 . The intermediate switching node of  claim 33 , wherein the communication channel availability table identifies for each port of the intermediate switching node:
 an adjacent switching node connected to that port;   communication channels provided on that port; and   whether each communication channel provided on that port is currently occupied or currently available.   
     
     
         36 . The intermediate switching node of  claim 30 , wherein the communication channel is an optical channel. 
     
     
         37 . The intermediate switching node of  claim 36 , wherein the optical channel is an optical wavelength channel. 
     
     
         38 . The intermediate switching node of  claim 37 , wherein the optical wavelength channel is an optical wavelength channel on a wavelength division multiplexed link. 
     
     
         39 . The intermediate switching node of  claim 30 , wherein the connection initiation communication is received at the first terminal switching node from customer premises equipment requesting the connection. 
     
     
         40 . The intermediate switching node of  claim 30 , configured to send a connection deny communication to the previous switching node when the current switching node cannot identify a communication channel identifier for a communication channel that is available on a link between the current switching node and the previous switching node. 
     
     
         41 . The intermediate switching node of  claim 30 , configured to send a connection deny communication to the previous switching node when the communication is a connection deny message. 
     
     
         42 . A source switching node configured to establish an optical connection between the source switching node and a destination switching node via zero or more intermediate switching nodes along a path in an optical network, wherein an initial connection request communication is sent to the source switching node upon initially requesting the connection, the source switching node being configured to:
 receive a communication from an adjacent switching node along the path;   if the communication is a connection initiation communication, forward a connection request communication to the next switching node along the path; and   if the communication is a connection confirm communication, establish a connection to the previous switching node along the path using the previously stored available communication channel.   
     
     
         43 . The source switching node of  claim 42 , wherein each connection request communication comprises a connection request message. 
     
     
         44 . The source switching node of  claim 42 , wherein each connection confirm communication comprises a connection confirm message. 
     
     
         45 . The source switching node of  claim 42 , wherein the source switching node is configured to:
 store a routing table identifying a next hop switching node for the path; and   store a communication channel availability table identifying any communication channels not yet allocated to connections.   
     
     
         46 . The source switching node of  claim 45 , wherein the routing table identifies a respective next hop switching node for a respective path between each possible pair of source and destination switching nodes. 
     
     
         47 . The source switching node of  claim 45 , wherein the communication channel availability table identifies for each port of the source switching node:
 an adjacent switching node connected to that port;   communication channels provided on that port; and   whether each communication channel provided on that port is currently occupied or currently available.   
     
     
         48 . The source switching node of  claim 42 , wherein the communication channel is an optical channel. 
     
     
         49 . The source switching node of  claim 48 , wherein the optical channel is an optical wavelength channel. 
     
     
         50 . The source switching node of  claim 48 , wherein the optical wavelength channel is an optical wavelength channel on a wavelength division multiplexed link. 
     
     
         51 . The source switching node of  claim 50 , wherein the connection initiation communication is received at the source switching node from customer premises equipment requesting the connection. 
     
     
         52 . The source switching node of  claim 42 , configured to send a connection deny communication to a source of the connection initiation request when the communication is a connection deny communication. 
     
     
         53 . The source switching node of  claim 42 , configured to send a communication deny communication to customer premises equipment that sent the connection initiation request when the communication is a connection deny communication. 
     
     
         54 . The source switching node of  claim 42 , configured to send a connection deny communication to the source when the communication is a connection initiation communication received from a source, the connection initiation communication identifies at least one acceptable signal format, and the source switching node cannot confirm that a channel having a signal format matching at least one signal format of the at least one acceptable signal format is available. 
     
     
         55 . A destination switching node configured to establish an optical connection between a source switching node and the destination switching node via zero or more intermediate switching nodes along a path in an optical network, the destination switching node being configured to:
 receive a communication from an adjacent switching node along the path;   if the communication is a connection request communication, then:
 identify a communication channel identifier for a communication channel that is available on a link between the current switching node and the previous switching node; and 
 establish a connection using the available communication channel and to send a connection confirm communication to the previous switching node. 
   
     
     
         56 . The destination switching node of  claim 55 , wherein each connection request communication comprises a connection request message. 
     
     
         57 . The destination switching node of  claim 55 , wherein each connection confirm communication comprises a connection confirm message. 
     
     
         58 . The destination switching node of  claim 55 , wherein the communication channel is an optical channel. 
     
     
         59 . The destination switching node of  claim 58 , wherein the optical channel is an optical wavelength channel. 
     
     
         60 . The destination switching node of  claim 59 , wherein the optical wavelength channel is an optical wavelength channel on a wavelength division multiplexed link.