meant to cc cerowrt-devel on this...
---------- Forwarded message ---------- From: Dave Taht <[email protected]> Date: Sun, May 25, 2014 at 12:55 PM Subject: qos in open commotion? To: [email protected], [email protected] Dear Andy: In response to your thread on qos in open commotion my list started a thread https://lists.bufferbloat.net/pipermail/cerowrt-devel/2014-May/003044.html summary: You can and should run packet scheduling/aqm/qos in routers with 32MB of memory or less. Some compromises are needed: https://lists.bufferbloat.net/pipermail/cerowrt-devel/2014-May/003048.html FIRST: We strongly recomend that your edge gateways have aqm/packet scheduling/qos on all their connections to the internet. See innumerable posting on bufferbloat and the fixes for it... http://gettys.wordpress.com/ Feel free to lift cerowrt's SQM scripts and gui from the ceropackages repo for your own purposes. Openwrt barrier breaker qos-scripts are pretty good too but don't work with ipv6 at the moment... http://www.bufferbloat.net/projects/cerowrt/wiki/Setting_up_SQM_for_CeroWrt_310 For the kind of results we get on cable: http://snapon.lab.bufferbloat.net/~cero2/jimreisert/results.html Wifi has a built in QoS (802.11e) system but it doesn't work well in congested environments and optimizing wireless-n aggregation works better. As for fixing wifi, well, we know what to do, but never found any funding for it. Ath9k is still horribly overbuffered and while fq_codel takes some of the edge off of wifi (and recently we disabled 802.11e entirely in favor of fq_codel), and in cerowrt we reduce aggregation to get better latency also - much more work remains to truly make it scale down to levels of latency we consider reasonable while (In other words, wifi latencies suck horribly now no matter what yet we think we know how to improve that. Feel free to do measurements of your mesh with tools like netperf-wrapper. There are also a few papers out there now showing how bad wifi can get nowadays) As for replacing pfifo_fast, openwrt barrier breaker replaced pfifo_fast with fq_codel in barrier breaker a year ago. fq_codel by default is essentially zero cost (64k per interface*hw queues) and the default in openwrt on all interfaces by default now... but the typical router cpus are so weak it is rare it kicks in except at 100mbit and below. (where it can be wonderful) - and it's on a rate limited (eg dsl or cable) system where it's most obviously useful. Presently. Lastly, I've been running a deployed babel mesh network for 2 years with fq_codel in it, 2 SSIDs per nanostation m5 and picostation, and it runs pretty good. Recent tests on the ubnt edgerouter went well, as well... Please give this stuff a shot. Your users will love it. -- Dave Täht NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_0296_indecent.article -- Dave Täht NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_0296_indecent.article _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
