VIRTUAL ROUTERS FOR GMPLS NETWORKS
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.