BBR is pretty awesome, and it's one of the reasons why I stopped sweating inbound rate limiting + fq_codel as much as I used to. I have a blog entry pending on this but wasn't expecting the code to be released before the paper was... and all I had to go on til yesterday was Nowlan's dissertation:
http://blog.cerowrt.org/papers/bbr_thesis.pdf which seemed closer to good than anything I'd read before, but still wrong in a few respects, which has taken a few years to sort out. I think reading the upcoming acm queue paper is going to be fun! I think they have identified the right variables to probe - RTT and bandwidth, in sequence - for modern congestion control to work much better. Still BBR makes a few assumptions that do not hold (or so I think) - with wifi in the control loop, and it needs wider testing in more circumstances than just google facing out - like on itty bitty nas's and media servers - and especially seeing what happens when it interacts with fq_codel and cake would be good to see. I've watched youtube be *excellent* for 2 years now, and only had the faintest hints as to why. It was quite amusing that the original patchset didn't compile on 32 bit platforms. And make no mistake - it still makes plenty of sense to apply fq_codel-like algorithms to routers, and the stuff we just did to wifi for fq_codel and airtime fairness. Had I thought BBR solved everything I'd have quit years ago. On Sat, Sep 17, 2016 at 11:34 AM, Maciej Soltysiak <[email protected]> wrote: > Hi, > > Just saw this: https://patchwork.ozlabs.org/patch/671069/ > > Interested to see how BBR would play out with things like fq_codel or cake. > > "loss-based congestion control is unfortunately out-dated in today's > networks. On > today's Internet, loss-based congestion control causes the infamous > bufferbloat problem" > > So, instead of waiting for packet loss they probe and measure, e.g. when > doing slow start (here called STARTUP) they don't speed up until packet > loss, but slow down before reaching estimated bandwidth level. > > Cake and fq_codel work on all packets and aim to signal packet loss early to > network stacks by dropping; BBR works on TCP and aims to prevent packet > loss. > > > Best regards, > Maciej > > > _______________________________________________ > Cerowrt-devel mailing list > [email protected] > https://lists.bufferbloat.net/listinfo/cerowrt-devel > -- Dave Täht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
