Co-scheduling computational and networking resources in elastic optical networks

Today´s applications such as cloud computing and e-science involve the processing of complex jobs consisting of several inter-dependent tasks executing on heterogeneous clusters of computing resources, which are interconnected by high-speed optical networks. The emerging technology of flexible grid through the use of Optical Orthogonal Frequency-Division Multiplexing (OOFDM) allows fiber bandwidth to be more suitably matched up with application requirements, thereby making the network more elastic. This is done by partitioning the bandwidth into hundreds or even thousands of OFDM subcarriers that may be allocated to services. An important problem in such applications is the joint scheduling (or co-scheduling) of computational and network resources. In this paper, we formulate a problem of co-scheduling computational and networking resources to multiple jobs in elastic optical networks. We consider both static and dynamic versions of the problem; in the static case, our objective is to minimize the makespan of all the jobs, while minimizing the job blocking is the aim when jobs arrive dynamically. We formulate an integer-linear program for the static version of the problem. Two efficient heuristics are then proposed and compared. Simulation results are presented to demonstrate the effectiveness of the proposed approaches.