Explore a conference talk on adapting TCP for reconfigurable datacenter networks (RDCNs). Learn about the challenges of utilizing high-bandwidth circuits in modern RDCNs with microsecond-scale reconfiguration delays. Discover two innovative solutions: dynamic resizing of top-of-rack switch virtual output queues and an endpoint-based approach using explicit circuit state feedback. Gain insights into the open-source RDCN emulator, Etalon, and understand how these techniques significantly improve circuit utilization with minimal impact on tail latency. Delve into the intricacies of TCP performance in rapidly changing network environments and the importance of quick adaptation for efficient use of reconfigurable circuits in datacenter networks.