M2SDN: Achieving Multipath and Multihoming in Data Centers with Software Defined Networking

The increasing virtualization in data centers brings growing inter-node communication by running various applications on virtual machines located physically separated. Meanwhile, the virtual machines on a physical server also compete for limited Ethernet interface I/O resources. Load balancing with multipath and multihoming is usually the key to address the bandwidth and Ethernet I/O bottlenecks. Even though various variants of equal cost multipath (ECMP) schemes have been widely applied for load balancing, the equal and fairness assumption of ECMP results in imbalance and underutilization in asymmetric networks without considering network topology and traffic situation. The multihoming solutions usually require protocol modification and peer's support. In this paper, we propose a utilization & topology-aware multipath routing and multihoming scheduling with Software Defined Networking (SDN) in data centers to address these bottlenecks. The utilization & topology-aware multipath routing takes global network situation to avoid congestions and balances utilization of multiple paths. At a multi-homed server end, the multihoming scheduler balances the traffic among multiple Ethernet interfaces and ensures QoS guarantees when accessing the network without changing network stack. We compared our approach with traditional single path and equal cost multipath schemes, and the results showed that the utilization & topology-aware multipath routing and multihoming scheduling achieved much higher network utilization and better load balancing, especially for asymmetric networks.