BBR, the new kid on the TCP block

Any data on BBR vs Reno and Vegas sharing?

Link capacity estimation is easy. It's the co-existing gracefully with all other flow control options that's tricky.

There is also no mention of how it handles things like wireless links with high jitter and intermittant not related to flow rate packet loss.

Well it does mention that BBR uses "The RTT is the minimum of all RTT measurements over some time window that is described as “tens of seconds to minutes”." This is a much larger measuring window than previous RTT tracking TCP. At 10s of seconds it is also hopefully enough to tackle the most common forms of jitter and intermittent flows.

At truly bad flow characteristics you need to start some truly weird line coding methods with stream data split over multiple packets with redundant coding to rebuild dropped packets etc, but this kind of thing just kills latency.

There's a 'Sharing' section near the end where two scenarios are compared. Doesn't look like an exhaustive test, rather the opposite.

Sure, I read the article. That section covers just CUBIC.

It also doesn't discuss competition between BBR users. Playing nicely with your neighbors is important for the health of the Internet.

It doesn't discuss competition with either many users, with things like webrtc, or with those evil dial-a-speed schemes.

The internet is complex.

However, since the dial-a-speed evildoers haven't caused much controversy in the grand scheme of things, I don't think BPR will do real harm in that case.

I'm more concerned about unloaded parts of a circuit. Suppose some BPR streams fill one hop, and share other, higher-capacity, hops with Reno. Does Reno do as well then as it would if the BPR streams were Reno?

Several BBR flows do actually converge quite nicely to a fair share of bandwidth. Take a look at the presentation the guys from google gave at the IETF 97 in Seoul: https://www.ietf.org/proceedings/97/slides/slides-97-iccrg-b...

I think there is also a recording of that session somewhere on youtube.

Also, the complete paper can be downloaded for free at http://queue.acm.org/detail.cfm?id=3022184

What about BBR sharing with BBR? Really, what is the reason this shouldn't be rolled out as the default everywhere?