SIRD - A Sender-Informed, Receiver-Driven Datacenter Transport Protocol

Learn about SIRD, a novel receiver-driven congestion control protocol for datacenter networks that addresses the throughput-buffering trade-off in this 17-minute conference presentation from NSDI '25. Discover how researchers from EPFL, UCSD, and Imperial College London developed a protocol that combines the benefits of receiver-driven scheduling for single-owner links with reactive control algorithms for shared network resources. Explore the key insight that enables receivers to precisely schedule their downlinks while coordinating over shared bottlenecks, including how SIRD treats sender uplinks as shared links to enable congestion feedback flow from senders to receivers. Examine the implementation details built on top of the Caladan stack that achieves 100Gbps throughput in software while maintaining minimal network queuing. Analyze comparative performance results against state-of-the-art receiver-driven protocols like Homa, dcPIM, and ExpressPass, as well as production-grade reactive protocols including Swift and DCTCP, demonstrating SIRD's unique ability to simultaneously maximize link utilization, minimize queuing, and achieve near-optimal latency in datacenter environments where packet buffer capacity continues to decline relative to network speeds.