Embedding and re-embedding of virtual links in software-defined multi-radio multi-channel multi-hop wireless networks

Abstract

There is rising interest in applying Software Defined Networking (SDN) principles to wireless multi-hop networks, as this paves the way towards bringing the programmability and flexibility that is lacking in today’s distributed wireless networks (ad-hoc, mesh or sensor networks) with the promising perspectives of better mitigating issues such as scalability, mobility and interference management and supporting improved controlled QoS services.This paper investigates this latter aspect and proposes an Integer Linear Programming (ILP) based wireless resource allocation scheme for the provision of point-to-point and point-to-multipoint end-to-end virtual links with bandwidth requirements in software-defined multi-radio multi-channel wireless multi-hop networks. The proposed algorithm considers the peculiarities of wireless communications: the broadcast nature of wireless links which can be leveraged for point-to-multipoint links resource allocations, and, the interference between surrounding wireless links. It also considers switching resource consumption of wireless nodes since, for the time being, the size of SDN forwarding tables remains quite limited. We also consider the case where the requirements of already embedded virtual links evolve over time and propose a re-embedding strategy that meets the new requirements while minimizing service disruption. Genetic Algorithms derived from the ILP formulations are also proposed to address the case of large wireless networks. Our simulation results show that our proposed methods work effectively compared to shortest path based heuristics.