Virtual routers for gmpls networks

Abstract

Virtual routers that abstract photonic sub-domains are provided for GMPLS networks. A virtual router uses a link viability matrix to keep track of the set of viable connections between inputs and outputs of a photonic sub-domain. A virtual router may receive RSVP-TE signaling messages and either allocate a working input to output link pair or, if explicitly signaled, verify that the requested link is currently viable. A virtual router also advertises, in its link state updates, the current set of possible outputs for any input link. Shortest path computations can be implemented utilizing virtual routers by modifying a topology graph in accordance with the link viability matrix of the virtual router.

1 . A method for determining a shortest path in a GMPLS network, the method comprising:
 receiving a portion of a link viability matrix, the link viability matrix expressing, for each input of a plurality of inputs in a photonic sub-domain, whether that input has a viable connection or lacks connectivity to each particular output of a plurality of outputs in the photonic sub-domain; and   modifying a GMPLS topology graph in accordance with the received portion of the link viability matrix.   
     
     
         2 . The method of  claim 1 , wherein modifying the topology graph comprises adding a node to the topology graph for each input/output in the photonic sub-domain having a viable connection to another input/output in the photonic sub-domain. 
     
     
         3 . The method of  claim 1 , wherein the portion of the link viability matrix is received from a photonic communications device of the photonic sub-domain. 
     
     
         4 . The method of  claim 3 , wherein the photonic communications device includes an optical controller operable to determine values in the link viability matrix. 
     
     
         5 . The method of  claim 1 , wherein the portion of the link viability matrix is received over the GMPLS network. 
     
     
         6 . The method of  claim 1 , wherein the method is performed at a routing element of the GMPLS network. 
     
     
         7 . The method of  claim 6 , further comprising transmitting on the GMPLS network an RSVP-TE message to initiate allocation of a viable connection to the routing element. 
     
     
         8 . The method of  claim 6 , further comprising transmitting on the GMPLS network an RSVP-TE message requesting a particular input/output pair to initiate verification that the particular input/output pair is a viable connection. 
     
     
         9 . A routing element for a GMPLS network having at least one photonic sub-domain, the routing element comprising:
 a receiver operable to receiving a portion of a link viability matrix, the link viability matrix expressing, for each input of a plurality of inputs in a photonic sub-domain, whether that input has a viable connection or lacks connectivity to each particular output of a plurality of outputs in the photonic sub-domain; and   GMPLS topology graph logic operable modify a GMPLS topology graph responsive to the received portion of the link viability matrix.   
     
     
         10 . The routing element of  claim 9 , wherein the GMPLS topology graph logic is operable to modify the topology graph by adding a node to the topology graph for each input/output in the photonic sub-domain having a viable connection to another input/output in the photonic sub-domain. 
     
     
         11 . The routing element of  claim 9 , further comprising a transmitter operable to transmit on the GMPLS network an RSVP-TE message to initiate allocation of a viable connection to the routing element. 
     
     
         12 . The routing element of  claim 9 , further comprising a transmitter operable to transmit on the GMPLS network an RSVP-TE message requesting a particular input/output pair to initiate verification that the particular input/output pair is a viable connection. 
     
     
         13 . The routing element of  claim 9 , wherein the receiver is operable to receive the portion of the link viability matrix from the GMPLS network.