N I ] 2 6 A ug 2 01 4 Space Shuffle : A Scalable , Flexible , and High-Bandwidth Data Center Network

The increasing need of cloud and big data applications requires data center networks to be scalable and bandwidth-rich. Current data center network architectures often use rigid topologies to increase network bandwidth. A major limitation is that they can hardly support incremental network growth. Recent work has been investigating new network architecture and protocols to achieve three important design goals of large data centers, namely, high throughput, routing and forwarding scalability, and flexibility for incremental growth. Unfortunately, existing data center network architectures focus on one or two of the above properties and pay little attention to the others. In this paper, we design a novel flexible data center network architecture, Space Shuffle (S2), which applies greedy routing on multiple ring spaces to achieve high-throughput, scalability, and flexibility. The proposed greedy routing protocol of S2 effectively exploits the path diversity of densely connected topologies and enables key-based routing. Extensive experimental studies show that S2 provides high bisectional bandwidth and throughput, near-optimal routing path lengths, extremely small forwarding state, fairness among concurrent data flows, and resiliency to network failures.