Congestion Control Protocols: Delay and ECN or both?

Monday, July 16, 2018 - 3:00pm

Event Calendar Category

Other LIDS Events

Speaker Name

Vishal Mishra


Columbia University

Building and Room Number



In this talk we explore the design space of feedback congestion control, for both the wide area Internet as well as data centers. We look at both end to end as well as in network approaches for congestion control, and two different kinds of feedback signals, delay and explicit congestion notification (ECN) and present the benefits and drawbacks for the approaches. For delay-based end to end congestion control, we present a fundamental impossibility result which states that the protocol can either be fair, or control the bottleneck delay to a fixed value but not both. Our result confirms the behavior observed for delay-based congestion control protocols for both recently proposed protocols like TCP BBR, as well as earlier approaches like TCP Vegas and protocols dating back to the mid-80s. Finally, we present a design that can combine the best of both delay and ECN based approaches for a unified protocol that works both in the data center and the WAN.


Vishal Misra is a Professor in the Department of Computer Science at Columbia University, with a joint appointment in the Electrical Engineering Department and a visiting scientist at Google. He is an IEEE Fellow and his research emphasis is on mathematical modeling of networking systems, bridging the gap between practice and analysis. He served as the Vice-Chair of the Computer Science Department at Columbia University from 2009 to 2011, and in 2011 he spun out Infinio, a company in the area of datacenter storage. He is also credited with inventing live-microblogging at CricInfo, a company he co-founded while a graduate student at UMass Amherst, predating Twitter by 10 years. CricInfo was later acquired by ESPN and is still the world most popular sports portal. He also played an active part in the Net Neutrality regulation process in India, where his definition of Net Neutrality was adopted both by the citizen's movement as well as the regulators, leading to the strongest Net Neutrality protections anywhere in the world.