Circuit switching under the radar with reactor

The potential advantages of optics at high link speeds have led to significant interest in deploying optical switching technology in data-center networks. Initial efforts have focused on hybrid approaches that rely on millisecond-scale circuit switching in the core of the network, while maintaining the flexibility of electrical packet switching at the edge. Recent demonstrations of microsecond-scale optical circuit switches motivate con-sidering circuit switching for more dynamic traffic such as that generated from a top-of-rack (ToR) switch. Based on these technology trends, we propose a prototype hy-brid ToR, called REACToR, which utilizes a combina-tion of packet switching and circuit switching to appear to end-hosts as a packet-switched ToR. In this paper, we describe a prototype REACToR con-trol plane which synchronizes end host transmissions with end-to-end circuit assignments. This control plane can react to rapid, bursty changes in the traffic from end hosts on a time scale of 100s of microseconds, sev-eral orders of magnitude faster than previous hybrid ap-proaches. Using the experimental data from a system of eight end hosts, we calibrate a hybrid network simula-tor and use this simulator to predict the performance of larger-scale hybrid networks.