Congestion-aware multicast plug-in for an SDN network operating system

The multicast framework that provides a network with multicast group management and a multicast routing algorithm is universal and exclusive, which leads to two shortcomings to multicast communication. First, the multicast framework's default multicast routing algorithm is not specially designed for congestion avoidance, which negatively affects the quality of service (QoS) of multicast trees. Second, customized multicast routing algorithms cannot be deployed over the framework. Therefore, the multicast framework cannot simultaneously satisfy the QoS requirements of different application scenarios. To overcome these two drawbacks, we propose an innovative multicast framework that can be deployed in parallel with the existing multicast framework as a multicast plug-in for an SDN network operating system. This promising feature makes it possible to use customized multicast routing algorithms and maintain compatibility with typical multicast applications. Furthermore, based on this multicast framework, we propose a delay-constrained multicast routing algorithm that borrows ideas from anycast to actively avoid traffic congestion in multicast trees. Experimental results show that the framework is feasible and performs well, especially in high-load situations.