Tidal-traffic-aware routing and spectrum allocation in elastic optical networks

With the growing popularity of 5G mobile communications, cloud and fog computing, 4K video streaming, etc., population distribution and migration have increasing influence on traffic distribution in metro elastic optical networks (EONs). Traffic distribution is further diversified according to people's tendency to use network services in different places at different times. We use the term "tidal traffic" to represent traffic distribution with strong disequilibrium in the time and space dimensions. Note that tidal traffic can potentially result in low bandwidth utilization and weak service capability, as network resources are not allocated properly. To address this problem, in this study, we first analyze traffic characteristics of access networks and metro networks, and mathematically formulate an onion tidal traffic model (OTTM) in EONs. Second, based on the traditional routing and spectrum allocation (RSA) algorithm, which provides end-to-end connection by allocating frequency slot resources in EONs, we propose two algorithms to enhance bandwidth efficiency based on the OTTM model. We call them pre-detour RSA (PD-RSA) and pre-detour k-shortest paths RSA (PDK-RSA). Next, we analyze the shortcomings of a benchmark algorithm named min-hop k-shortest paths RSA (MHK-RSA) under tidal traffic, and compare PD-RSA and PDK-RSA with MHK-RSA via simulation. Simulation results show that PD-RSA and PDK-RSA can effectively reduce at least 26% and 18% of blocking probability, respectively, compared to MHK-RSA with the same time complexity.