Hi Dave, If I'm understanding you correctly, you want Babel to say it's an ECN-capable transport to have it land in a shorter fq_codel queue. I'm not familiar with what configuration knobs fq_codel offers, but couldn't you instead configure fq_codel to filter based on DiffServ when deciding which queue a packet goes in? Barring that you could also imagine filtering on the UDP port number, but that sounds even less likely to be supported.
I think I agree with Juliusz here, I'd prefer Babel stay truthful and instead change how fq_codel reacts to it. David > On Sep 27, 2018, at 09:30, Dave Taht <[email protected]> wrote: > > On Wed, Sep 26, 2018 at 3:36 PM Juliusz Chroboczek <[email protected]> wrote: >> >>> - const int ds = 0xc0; /* CS6 - Network Control */ >>> + const int ds = 0xc2; /* CS6 - Network Control + ECN */ >> >> Nope. If we start lying about ECN, people will start disabling ECN in >> routers, which would not be a good thing. > > I appreciate the moral stance, and to a huge extent I share it ( > https://www.bufferbloat.net/projects/ecn-sane/wiki/dtaht_ecn_editorial/ > ) > > On the other hand the characteristics of ECN'd babel traffic (single > low volume flows) interact with fq_codel > well, only imparting delay on overload to those flows and affecting > other traffic minimally. It makes l3 based routing info behave more > like a control plane, and more similarly to 802.11s which does stuff > at the management frame layer underneath layer 2 with no congestion > control applied at all. > > I had at one point a patch that attempted to do more of the right > thing ( increasing the metric as per loss but not ever going infinite > ) but it was invasive. At some point in the coming year or two maybe > we'll be able to sit down and do more science on the ecn front but > it's quite a long list ( > https://www.bufferbloat.net/projects/ecn-sane/wiki/ ) with the usual > lack of bodies and funding. > > In the interim, I'd welcome more data from more deployments. Including mine. > > > > I > > -- > > Dave Täht > CEO, TekLibre, LLC > http://www.teklibre.com > Tel: 1-669-226-2619 > > _______________________________________________ > Babel-users mailing list > [email protected] > https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/babel-users _______________________________________________ Babel-users mailing list [email protected] https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/babel-users
