BBR (Bottleneck Bandwidth and Round-trip propagation time) is a set of congestion control algorithms released by Google in 2016 . It is especially suitable for use in a weak network environment with a certain packet loss rate. For example, Google uses BBR to enable internal and external networks to run more efficiently with higher throughput and lower latency. In such environments, the performance of BBR far exceeds traditional congestion control algorithms such as CUBIC.
BBR has been iteratively updated to version v3. Google claims that BBRv3 has been widely used internally and has performed well. They are actively submitting BBRv3 to the upstream Linux kernel mainline.
Google engineers attended the IETF 117 event in San Francisco at the end of July. According to the engineers, BBRv3 contains various fixes and algorithm updates. In addition, the packet retransmission rate of BBRv3 is reduced by 12%, and the latency is also slightly improved .
According to the plan, Google engineers will submit BBRv3 to the upstream Linux kernel mainline TCP/networking module in August, and upgrade the BBR module from v1 to v3 code. BBRv3 will be dual licensed under the GPL and BSD.
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