Decoupled scheduling in Store-and-Forward OCS networks

By introducing storage into Optical Circuit Switched (OCS) networks and storing delay-tolerant requests until off-peak hours, the networks can have better performance. Since scheduling a data transfer in SnF networks has to deal with the spatial and temporal arrangement of the request, it is much more complicated than the routing-alone problem. In our prior research, we proposed TS-MLG, a holistic approach to solve this problem, but the computational and spatial complexity of the approach is high, limiting its use in large scale networks. In this paper, we propose a decoupled solution and specific algorithms for both sub-problems. The solutions can reduce spatial and computational complexity from O(N2*L2) to O(N*L) with marginal sacrifice on network performance, in which N and L are respectively the number of network nodes and state changes in the network. Simulation results show that in a moderate sized network with frequent state changes, the computing time of request scheduling can be reduced by 600 times. We conclude that the decoupled SnF scheduling has the potential of analyzing SnF in large networks with frequent state changes.