Dynamic Multipath Routing With Traffic Grooming in OFDM-Based Elastic Optical Path Networks

Elastic optical networks employ flexible routing and spectrum allocation algorithms to support diverse services and heterogeneous traffic. By splitting a traffic request into multiple small-size subconnections and individually transmitting them through several optical paths, multipath routing algorithms can more flexibly utilize spectrum resources than single-path routing algorithms in dynamic scenario. However, due to the imperfect shape of optical filters deployed in the network, guard bands are typically inserted between two adjacent connections in spectrum domain and, thus, cannot be used to transmit data. When the traffic load is heavy, multipath algorithms severely suffer this spectrum waste from deploying many subconnections and result in lower spectrum efficiency than single-path routing. Moreover, multipath routing algorithms require more bandwidth-variable transponders (BVT), which may lead to a higher cost. In this paper, we propose a dynamic multipath routing algorithm with traffic grooming (MPTG) to tackle this problem of multipath routing under heavy traffic load. By aggregating small-size connections originated from the same source node and sharing common fiber links, traffic grooming enhances the network throughput, and also effectively reduce the BVT consumption. The simulation results show that our proposed MPTG algorithm dramatically reduced bandwidth blocking ratio and BVT usage compared with previous multipath routing algorithm.