3 ms·

> latency AIUI google uses BBR which attempts to not fill up buffers and thus only add minimal extra latency. Plus in many cases the last mile is the bottlenec

> latency AIUI google uses BBR which attempts to not fill up buffers and thus only add minimal extra latency. Plus in many cases the last mile is the bottleneck, in which case proper queue management on the router or its counterpart can keep the latency low. I think fq-pie is a mandatory part of docsis 3.1 for that reason. Congestion should only result in limited bandwidth, not in significant latency spikes, and youtube will automatically lower resolution anyway if available bandwidth is too low to sustain playback. So no changes should be needed at this point.

crazygringo 7y ago
I think you're talking about a theoretical best-case scenario for YouTube where I'm talking about the real world with videoconferencing. For people at home, the bottleneck is often something like their apartment building or block or neighborhood -- wherever their ISP didn't provision enough. Obviously "proper queue management" on your home router doesn't affect this. To the contrary, a series of routers full of buffers means that congestion absolutely does increase latency, and drastically. "Bufferbloat" is a known phenomenon. We may wish it didn't exist, but it does. So your claim that "no changes should be needed" to ensure videoconferencing latency is unimpacted is just wrong, and flat in the face of all real-world evidence. Have you ever tried personally using videoconferencing on a saturated network? This isn't theory... it's something you can try yourself. (I used to work in videoconferencing and latency caused by network congestion was the #1 quality issue.)
- ipython 7y ago
  I also wonder how much of this is caused by poorly tuned home WiFi setups. You have congested airwaves, poor channel choices (what’s this channel 2? Nobody’s on that!), and the tendency for everyone to run their access points on MAX power to increase their “range” - all ways to totally demolish real world multi client WiFi throughput.
- the8472 7y ago
  > Have you ever tried personally using videoconferencing on a saturated network? Yes, my domestic connection often is saturated by p2p software. My router is running CAKE, thus video conferencing runs fine even when the link is close to saturation. > For people at home, the bottleneck is often something like their apartment building or block or neighborhood -- wherever their ISP didn't provision enough. In that case better AQM would have to be on those bottlenecks of course.

crazygringo 7y ago

I think you're talking about a theoretical best-case scenario for YouTube where I'm talking about the real world with videoconferencing. For people at home, the bottleneck is often something like their apartment building or block or neighborhood -- wherever their ISP didn't provision enough. Obviously "proper queue management" on your home router doesn't affect this. To the contrary, a series of routers full of buffers means that congestion absolutely does increase latency, and drastically. "Bufferbloat" is a known phenomenon. We may wish it didn't exist, but it does. So your claim that "no changes should be needed" to ensure videoconferencing latency is unimpacted is just wrong, and flat in the face of all real-world evidence. Have you ever tried personally using videoconferencing on a saturated network? This isn't theory... it's something you can try yourself. (I used to work in videoconferencing and latency caused by network congestion was the #1 quality issue.)

ipython 7y ago
I also wonder how much of this is caused by poorly tuned home WiFi setups. You have congested airwaves, poor channel choices (what’s this channel 2? Nobody’s on that!), and the tendency for everyone to run their access points on MAX power to increase their “range” - all ways to totally demolish real world multi client WiFi throughput.
the8472 7y ago
> Have you ever tried personally using videoconferencing on a saturated network? Yes, my domestic connection often is saturated by p2p software. My router is running CAKE, thus video conferencing runs fine even when the link is close to saturation. > For people at home, the bottleneck is often something like their apartment building or block or neighborhood -- wherever their ISP didn't provision enough. In that case better AQM would have to be on those bottlenecks of course.