Rising Stars 2020:

Rachee Singh

PhD Candidate

University of Massachusetts, Amherst / Microsoft Research

Areas of Interest

  • Information, Data, Network, and Communication Sciences
  • Operating Systems and Networking
  • Security


Rate adaptive wide area networks


Fiber optic cables connecting data centers are an expensive but important resource for large organizations. Their importance has driven a conservative deployment approach, with redundancy and reliability baked in at multiple layers. In this work, we take a more aggressive approach and argue for adapting the capacity of fiber optic links based on their signal-to-noise ratio (SNR). We investigate this idea by analyzing the SNR of over 8,000 links in an optical backbone for a period of three years. We show that the capacity of 64% of 100 Gbps IP links can be augmented by at least 75 Gbps. Moreover, adapting link capacity to a lower rate can prevent up to 25% of link failures. Our analysis shows that using the same links, we get higher capacity, better availability, and 32% lower cost per gigabit per second. To accomplish this, we propose Rate Adaptive WAN (RADWAN), a traffic engineering system that allows optical links to adapt their rate based on the observed SNR to achieve higher throughput and availability while minimizing the churn during capacity reconfigurations. We evaluate RADWAN using a testbed consisting of 1,540 km fiber with 16 amplifiers and attenuators. We then simulate the throughput gains of RADWAN at scale and compare them to the gains of state-of-the-art traffic engineering systems. Our data-driven simulations show that RADWAN improves the overall network throughput by 40% while also improving the average link availability.


Rachee Singh is a researcher in the Mobility and Networking group at MSR Redmond. Her research interests are in computer networking with a focus on wide area network performance and monitoring. She is a 2018 Systems and Networking Google PhD fellow. In a previous life, Rachee developed routing protocol features for Ethernet switches at Arista Networks.

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