Circuit Switching Under the Radar with REACToR


He Liu, Feng Lu, Alex Forencich, Rishi Kapoor, Malveeka Tewari, Geoffrey M. Voelker, George Papen, Alex C. Snoeren, and George Porter, University of California, San Diego


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 considering 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 hybrid ToR, called REACToR, which utilizes a combination of packet switching and circuit switching to appear to end-hosts as a packet-switched ToR. In this paper, we describe a prototype REACToR control 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, several orders of magnitude faster than previous hybrid approaches. Using the experimental data from a system of eight end hosts, we calibrate a hybrid network simulator and use this simulator to predict the performance of larger-scale hybrid networks.

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@inproceedings {179749,
author = {He Liu and Feng Lu and Alex Forencich and Rishi Kapoor and Malveeka Tewari and Geoffrey M. Voelker and George Papen and Alex C. Snoeren and George Porter},
title = {Circuit Switching Under the Radar with REACToR},
booktitle = {11th {USENIX} Symposium on Networked Systems Design and Implementation ({NSDI} 14)},
year = {2014},
isbn = {978-1-931971-09-6},
address = {Seattle, WA},
pages = {1--15},
url = {},
publisher = {{USENIX} Association},
month = apr,

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