Multicast routing with uncertain sources in software-defined network

Abstract

Multicast is designed to jointly deliver content from a single source to a set of destinations. It can efficiently save the bandwidth consumption and reduce the load on the source. The appearance of SDN provides opportunities to deploy flexible protocols, including multicast and its variants. However, in many important applications, it is not necessary that the source of a multicast transfer has to be in specific location as long as certain constraints are satisfied. Such facts bring a novel multicast with uncertain sources, abbreviated as uncertain multicast. It brings new opportunities and challenges to reduce the bandwidth consumption. In this paper, we focus on the uncertain multicast and construct a forest with the minimum cost (MCF), to enable that each destination reaches to one and only one source. Prior approaches, relying on traditional multicast, remain inapplicable to the MCF problem. Therefore, we propose two (2+ε)-approximation methods, named P-MCF and E-MCF, which can be deployed in SDN controllers. We conduct experiments on our SDN testbed together with large-scale simulations under the random SDN network. All manifest that our MCF approach always occupies less network links and incurs less network cost for an uncertain multicast than the traditional Steiner minimum tree (SMT) of any related multicast, irrespective of the used network topology and the setting of multicast transmissions.