Google's BBRv3 TCP Congestion Control Showing Great Results, Will Be Upstreamed To Linux

Written by Michael Larabel in Google on 7 August 2023 at 12:00 AM EDT. 10 Comments
Google's open-source BBR TCP congestion control algorithm is widely used within Google and its v3 iteration is already proving a success within the company and they are working toward upstreaming BBRv3 into the mainline Linux kernel.

Google's BBR "Bottleneck Bandwidth and Round-trip propagation time" algorithm has proven superior to simple loss-based congestion control and has allowed for networks inside and outside of Google to operate more efficiently with higher throughput and lower latency.

BBRv3 slides

Google engineers presented at the IETF 117 event in San Francisco at the end of July. BBRv3 incorporates various fixes and algorithm updates. Google found BBRv3 to have a 12% reduction in the packet re-transmit rate and a slight latency improvement. BBRv3 is being made publicly available under a dual GPL and BSD license. Google engineers plan to propose mainlining BBRv3 into the Linux kernel TCP/networking code in August. The plan is to upgrade the BBR module to the v3 code from v1.

BBRv3 slides

BBRv3 slides

See the Google slide deck for more details on BBRv3. For the time being until the BBRv3 code is upstreamed to the mainline kernel, you can find the BBRv3 code via this Google GitHub repository.
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