Jellyfish: Networking Data Centers Randomly

Industry experience indicates that the ability to incre-mentally expand data centers is essential. However, ex-isting high-bandwidth network designs have rigid struc-ture that interferes with incremental expansion. We present Jellyfish, a high-capacity network interconnect which, by adopting a random graph topology, yields it-self naturally to incremental expansion. Somewhat sur-prisingly, Jellyfish is more cost-efficient than a fat-tree, supporting as many as 25 % more servers at full capacity using the same equipment at the scale of a few thousand nodes, and this advantage improves with scale. Jellyfish also allows great flexibility in building networks with different degrees of oversubscription. However, Jelly-fish’s unstructured design brings new challenges in rout-ing, physical layout, and wiring. We describe approaches to resolve these challenges, and our evaluation suggests that Jellyfish could be deployed in today’s data centers.