Impossibility Results for Data-Center Routing with Congestion Control and Unsplittable Flows
Miguel Alves Ferreira, Nirav Atre, Justine Sherry, J.L. Sobrinho · 2024
Clos networks have a long history in networking. In early telephone networks and classic network flow problems, Clos networks have been shown to emulate the performance properties of an ideal macro-switch connecting sources to destinations. Therefore, Clos networks are a natural choice for modern data-centers, and are widely deployed. However, data-centers operate on different traffic assumptions than those prevalent in telephone networks and network flow problems: sources and destinations are not limited to at most one flow, and each flow must be assigned to a single path. Subject to these constraints, the performance of a Clos network is no longer equivalent to that of a macro-switch.