Bandwidth-variable optical transport network with adjustable time-modulated and inverse-multiplexed wavelength channels

This paper presents a bandwidth-variable and optical-groomable (BVOG) transport network architecture based on time-modulated optical cross-connects that enables efficient switching of periodic burst-sequenced traffic in addition to wavelength streaming traffic; with an elastic control plane that shapes each sub-wavelength traffic stream at the network edge into a sequence of periodic bursts, and inverse-multiplexes a supra-wavelength traffic stream into a group of multiple wavelength traffic streams and a potential sub-wavelength traffic stream to match the bandwidth requirement. BVOG network enables variable-time-slotted lightpaths with variable-length time slots to meet the bandwidth requirements of sub-wavelength traffic; and inverse-multiplexed lightpath-group (IM-lightpath-group) with variable group size to meet the bandwidth requirements of supra-wavelength traffic. For the problem of “routing and wavelength and time assignment” (RWTA) for sub-wavelength traffic; this paper presents an optimal integer linear programming (ILP) formulation that maximizes total network throughput, and a heuristic algorithm to minimize the blocking probability of future connection requests. For the problem of “inverse-multiplexed routing and wavelength assignment” (IMRWA) for supra-wavelength traffic; this paper presents an optimal ILP formulation that minimizes the total number of hops and the total per-hop propagation delays of the IM-lightpath-group, and a heuristic algorithm that minimizes the total number of wavelength channels of the IM-lightpath-group. The RWTA ILP is solved by the ILOG CPLEX optimization tool, and it is used to check the optimality of the RWTA heuristic. Performance tuning of the IMRWA heuristic is investigated to balance the tradeoff between performance and computation complexity. Performance tuning of the BVOG network with the RWTA and IMRWA heuristic is examined through simulation experiments.