Athena: Reliable multicast for group communication in SDN-based data centers

Several data center applications such as Hadoop and OpenStack VM provisioning utilize group communication (one-to-many or many-to-many transfers). Since these applications require reliable and stable delivery, they rely on TCP for all group communications. Even though multicast lends itself naturally to these group communication patterns, it has remained largely under-deployed in the Internet owing to concerns around reliability and stability. However, data center networks, with their structured topologies and centralized control using Software Defined Networking (SDN) present an opportunity to address these concerns. In this paper, we explore the feasibility of using reliable and stable multicast for all group communications inside SDN based data centers. We present the design and implementation of Athena-a platform that enables multicast in SDN based data centers for group communication in applications. Athena enables reliable multicast to ensure that no data is lost, and congestion control to ensure that other TCP flows in the network are not starved. We show practicability of Athena by enhancing OpenStack VM provisioning to use our platform. Our experiments on a physical testbed demonstrate that Athena improves VM provisioning time for typical batch size comprising five VM's by 2.5 times.