Am Wed, 21 Sep 2016 07:30:40 -0700 schrieb Grant <emailgr...@gmail.com>:
> [...] > [...] > >> > >> > >> I just remembered that our AT&T modem/router does not respond to > >> pings. My solution is to move PPPoE off of that device and onto my > >> Gentoo router so that pings pass through the AT&T device to the > >> Gentoo router but I haven't done that yet as I want to be on-site > >> for it. Could that behavior somehow be contributing to this > >> problem? There does seem to be a clear correlation between user > >> activity at that location and the bad server behavior. > > > > If that device behaves badly in router mode by blocking just all > > icmp traffic instead of only icmp-echo-req, this is a good idea. > > You may want to bug AT&T about this problem then. It should really > > not block related icmp traffic. > > > Hi Kai, yesterday I switched my Gentoo router over to handling PPPoE > and pings seem to be working properly now. The AT&T device is now > functioning as a modem only and passing everything through. Today > I'll find out if it helps with TCP Queuing and (supposedly) related > http response slowdowns. You may want to set the default congestion control to fq-codel (it's in the kernel) if you're using DSL links. This may help your problem a little bit. It is most effective if you deploy traffic shaping at the same time. There was once something like wondershaper. Trick is to get the TCP queuing back inside your router (that is where you deployed pppoe) as otherwise packets will queue up in the modem (dsl modems use huge queues by default). This works by lowering the uplink bandwith to 80-90% of measured maximum upload (the excess bandwidth is for short bursts of traffic). Traffic shaping now re-orders the packets. It should send ACK and small packets first. This should solve your queuing problem. Between each step check dslreports.com for bufferbloat. I'm guessing it is currently way above 1000 ms while it should stay below 20-50 ms for dsl. The fq-codel congestion control fights against buffer bloat. But it can only effectively work if you're doing traffic shaping at least on your uplink (downlink may or may not be worth the effort depending on your use-case). Additionally, you can lower the priority of icmp-echo-reply this way so during icmp flooding your uplink will still work. This link may help you: https://www.bufferbloat.net/projects/codel/wiki/Cake/ -- Regards, Kai Replies to list-only preferred.
