Colloquium Details

BBR Congestion Control

Speaker: Neal Cardwell, Google

Location: 60 Fifth Avenue C15

Date: December 12, 2017, 11 a.m.

Host: Anirudh Sivaraman


This talk will introduce BBR, a ground-up redesign of Internet congestion control - the algorithm that decides how fast to send data over the network. The talk will discuss the motivations for BBR, its design, implementations, performance results, and deployment at Google for TCP and QUIC (it will also introduce QUIC, a new always encrypted user-space UDP-based transport). BBR is now used for all TCP and QUIC Internet traffic from, YouTube, and Google Cloud, and all TCP traffic between Google data centers. BBR is available as open source for Linux TCP and QUIC, and an implementation is under way for FreeBSD TCP at Netflix.

BBR was a close collaboration between Neal Cardwell, Yuchung Cheng, C. Stephen Gunn, Soheil Hassas Yeganeh, and Van Jacobson - all members of Google's make tcp-fast project. The goal of this project is to evolve Internet transport via fundamental research and open source software. Contributions of the project include TFO (TCP Fast Open), TLP (Tail Loss Probe), RACK loss recovery, fq/pacing, BBR congestion control, and a large fraction of the git commits to the Linux kernel TCP code for the past five years. Team member Van Jacobson wrote the original TCP congestion control algorithm that has been the Internet standard for the past 30 years.

Speaker Bio:

Neal Cardwell is a senior staff software engineer in Google's NYC office. He entered the UC Berkeley PhD program in 1996 and then followed his advisor, Tom Anderson, to the University of Washington, where he completed an MS in 1999, with research in the area of TCP congestion control. He worked at Steve McCanne's FastForward Networks from 1999 to 2002. He has worked at Google since 2002, on projects including GFE (the Google Front End proxying all traffic for, Googlebot (Google's web crawler), routing performance, the open source Packetdrill network stack testing tool, and Linux TCP congestion control and loss recovery. He is currently a member of the Congestion Control team at Google, and his recent focus has been BBR congestion control.

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