RDC: Energy-Efficient Data Center Network Congestion Relief with Topological Reconfigurability at the Edge

The rackless data center (RDC) is a novel network architecture that logically removes the rack boundary of traditional data centers and the inefficiencies that come with it. As modern applications generate more and more inter-rack traffic, the traditional architecture suffers from contention at the core, imbalanced bandwidth utilization across racks, and longer network paths. RDC addresses these limitations by enabling servers to logically move across the rack boundary at runtime. Our design achieves this by inserting circuit switches at the network edge between the ToR switches and the servers, and by reconfiguring the circuits to regroup servers across racks based on the traffic patterns. We have performed extensive evaluations of RDC both in a hardware testbed and packet-level simulations and show that RDC can speed up a 4:1 oversubscribed network by 1.78× ∼ 3.9× for realistic applications and more than 10× in large-scale simulation; furthermore, RDC is up to 2.4× better in performance per watt than a conventional non-blocking network.