Minimizing Request Blocking in Survivable Transparent OFDM Based Optical Grids

As Orthogonal Frequency Division Multiplexing (OFDM) allows flexible spectrum allocation, OFDM based optical grids have replaced traditional Wavelength Division Multiplexed (WDM) optical grids. Since a fiber-cut is the most common failure in optical networks and grids process resource intensive tasks, survivability is a key issue in designing optical grids. In a dynamic scenario, spectral fragmentation arises due to random arrival and departure of requests, leading to blocking of new requests. In this paper, we address the problem of survivability and minimizing request blocking in a dynamic scenario in OFDM based transparent optical grids. We propose a dynamic survivable route and spectrum allocation strategy. Time complexity analysis of the proposed algorithm Blocking Minimized Survivable Routing and Spectrum Allocation (BMSRSA), shows that it runs in polynomial time. Furthermore, intensive simulation experiments and performance comparisons with a well-known strategy show that the proposed strategy can lead to appreciable reduction in request blocking probability.