An Efficient MPLS-Based Source Routing Scheme in Software-Defined Wide Area Networks(SD-WAN)

Software Defined Networks (SDN) is a promising network paradigm that offers flexibility, efficiency and fine-grained control over forwarding Elements (FE) by decoupling control and data planes. The forwarding decision is often made by the controller by managing flow table entries in the switches. Certainly, flow table management raises a lot of concerns and various schemes have been proposed such as the traditional Hop by-Hop Forwarding scheme. Studies have proved that this scheme may lead to performance degradation due to a huge control traffic and a massive flow table consumption. To reduce performance degradation, source routing was proposed. Unfortunately, this may also lead to significant bandwidth overhead, particularly in large-scale networks. This paper deals with the concept of source routing using MPLS labels. Basically, our scheme ensures flexibility and is suitable for application both in SD-LAN and SD-WAN by supporting various n-port switches (n >= 4). Using a MaxHop clustering algorithm, the network is divided into several sections. In each section, a trade-off between control traffic overhead, bandwidth overhead and flow table usage is achieved using a linear weighted scalarization of the Multi-Objective optimization problem. Finally, we present the theta-MOBO algorithm to be run by the controller. Simulation results show that the proposed scheme outperforms parallel solutions such as MPLS label-based forwarding [1] [2] and Hop-by-Hop forwarding [3] schemes in terms of the bandwidth overhead and flow rejection rate.