Network Dimensioning and Survivability of Orthogonal Frequency Division Multiplexed Transparent Optical Grids: An Online Relocation Based Solution

Due to the high bandwidth and low latency, optical networks have emerged as ideal candidates for supporting grid applications. As optical Wavelength Division Multiplexed (WDM) networks migrate to the next generation of flexible Orthogonal Frequency Division Multiplexed (OFDM) networks, it becomes necessary for the grid applications to be supported in the next generation of optical grids. As survivability is a key issue in optical grids, we address the problem of online network dimensioning and survivability of OFDM based optical grids. The most common cause of failure is known to be a fibre cut and so in this paper we have addressed the problem of protecting OFDM based transparent optical grids against any arbitrarily single link failure. For ensuring survivability we have used shared path protection. For network dimensioning we have used the well-known anycast principle for optical grids: a job can be relocated to another resource (or server) of similar type. To the best of our knowledge, this is the first paper to address the problem of online dimensioning and survivability of OFDM based transparent optical grids. We first propose an Integer Linear Program (ILP) formulation for the problem and then a heuristic algorithm, Online Dimensioning with Shared Path Protection (ODSPP) that can solve the problem in polynomial time. We compare the results obtained from the heuristic with that of the ILP and traditional shared path protection (SPP) without relocation. Performance comparisons show that ODSPP is highly capacity efficient and can be used to obtain near optimal results. The average percentage decrease in connection blocking probability over all experiments using ODSPP is 20.07 percent