Starfish: A Topology-Routing Co-Design for Small-Scale Data Centers#

Anchengcheng Zhou (Princeton), Vipul Harsh (Conviva), Sangeetha Abdu Jyothi (UC Irvine), Maria Apostolaki (Princeton), Brighten Godfrey (UIUC)

• Why: Almost all DC topology research targets hyperscalers, yet most real data centers run hundreds to a few thousand servers on leaf-spine with painful cost/oversubscription tradeoffs. This is a rare, rigorous design for that population — directly useful if your fleet is enterprise/colo-scale rather than 100K-GPU.
• What: A topology-routing co-design (DRing topology + adaptive routing) that supports 56% more traffic than an equal-cost leaf-spine on real traces with the same equipment. The routing scheme also generalizes to expander topologies, where it yields 52% more traffic than leaf-spine — fixing expander designs' biggest deployment hurdle (no practical routing).
• How: DRing spreads servers across all switches to raise per-server egress capacity and expose diverse near-shortest paths; routing exploits DRing's structural properties and adapts to traffic using standard hardware and protocols — no exotic switching required.
• Where applicable: Small-to-mid data centers (hundreds–thousands of servers); uses standard equipment and protocols, making it unusually deployable for a topology paper. Artifact evaluated (available/functional/reproduced).