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Ask HN: Internet magically gets faster when opening speedtest?

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Re: Ask HN: Internet magically gets faster when opening speedtest?

#271

Post by fy20 »

formerly_proven wrote: post #37
CraigJPerry wrote: post #32

Earlier quoted context omitted.

Ha! I'm currently down the rabbithole of trying to understand why when connected through nordvpn, i'm seeing ~5% faster download and ~10% lower ping latency to speedtest.net when connected to an in-country vpn endpoint. Does not compute. Compression? I can't explain the lower ping, traffic shaping?

> I can't explain the lower ping, traffic shaping? Better routes. Most latency on the internet is not due to c.

I get this same with AWS. The routes to my country in Northern Europe from us-* are terrible (eu-* is fine), to the point where a download from S3 during peak times can be tens of kB/s. If I connect to a VPN in another country it jumps to tens of MB/s.

Re: Ask HN: Internet magically gets faster when opening speedtest?

#272

Post by PaulDavisThe1st »

tylersmith wrote: post #251
PaulDavisThe1st wrote: post #232

Earlier quoted context omitted.

The EFF was fairly happy with the FCC's Title II proposal back in 2015: https://www.eff.org/deeplinks/2015/02/huge-win-open-internet... In 2018 Markey and others proposed simply overturning Pai/Trump's overtuning of Title II. I don't know precisely what you're referring to ... the closest I could find was the EFF's objections to the FCC proposals from 2011 which had things like "vague QoS and general network operatio…

What does the EFF's happiness have to do with anything?

I consider them one of the most on-point organizations in the fight for actual net neutrality.

Re: Ask HN: Internet magically gets faster when opening speedtest?

#274

Post by robbedpeter »

I have to use my VPN to get any sort of performance. My isp throttles the shit out of everything, but they're usually a couple months behind my VPN provider, and when they catch up I switch. I just want the fucking service I pay for without the doodlefuckery.

Re: Ask HN: Internet magically gets faster when opening speedtest?

#275

Post by yareth »

Yes, that is common. Back when I used to work for an ISP, all of our main competitors have whitelisted speedtest servers to sidestep their shaping and sometimes even ran their own, just to look good on the results page. The fact that other webs instantly load might be just an implementation quirk; the QoS might get reset for a second when loading the speedtest page.

You can see what ISP traffic shaping actually does when you have a server on reliable backbone link outside of given ISP network by trying to download or upload large file to it and measuring. Bandwidth changes usually aren't too smooth and often you can see "stairs" on measurement graph as the speed drops the more data you transmit.

This shows how the whole "speed UP TO xyz mbits" marketing trick really works.

Re: Ask HN: Internet magically gets faster when opening speedtest?

#276

Post by exikyut »

zinekeller wrote: post #270
LeoPanthera wrote: post #268

Earlier quoted context omitted.

> I just tried the cloudflare Speedtest and it doesn’t read low, in fact it read higher than what’s possible. Perhaps there is a confusion between megabytes, and megabits.

Unfortunately, no. I intentionally constrained an ethernet link at 10Mb (in the PHY layer, so any bugs in the network stack is irrelevant) and both Fast.com and Cloudflare misread the upload speeds up to 20 times (what should be 9.something Mbps became >200Mbps). Speedtest.net is immune to this, even using their browse client. I don't know what's causing this, but I've ruled out browser bugs. I haven't tested Google'…

You mean you told the PHY to renegotiate at 10M with something like `ethtool -s speed 10`?

While stumbling around attempting to figure out `tc qdisc` a while back I found that the shaping it was applying was very synthetic, such that asking for low bitrate and high latency would mean the kernel would just wait a second or two then shunt several KB of data through at once. IIRC I was just playing with the default approaches you'd find bandied about on tutorial websites and such. (I'm still looking for a way to synthetically limit a link in ways that are physically accurate.)

Remembering that experience got me thinking - without any idea what I'm talking about, I'm wondering if the PHY layer is doing something vaguely similarly stupid-simple that does technically limit the line rate to 10Mb at full blast, but still allows throughput to very briefly burst higher than that.

I think speedtest websites try to measure both the burst rate and the line rate, so perhaps something's gotten very tangled up on both the PHY and JS sides.

Now I'm curious what model PHY (well, NIC) you're using.

FWIW, Chrome's devtools has a network rate limiter built in (network tab, dropdown that says "No throttling", open that and hit "add"... aaaand remember that it's persistent (for just the tab) until you turn it back off :) lol)

Edit: Just found https://news.ycombinator.com/item?id=31063184 downthread describing seeing 100Mbps through a 10Mbit hub. I think you've either found a technical bug or a, uh, "the speedtest is good so my internet must be fine" "bug" (which would be very interesting).

Re: Ask HN: Internet magically gets faster when opening speedtest?

#277

Post by yareth »

dboreham wrote: post #68

Unlikely your suspicions are correct. Provisioning high QoS to the speedtest site is common practice (see fast.com for countermeasures), but changing the entire subscriber QoS because traffic to one particular destination is detected seems like too much work and doesn't really achieve anything useful. If you are on a wireless network (either your upstream from a WISP, or internally on your own network), then I'd susp…

From my experience about 8-10 years ago when the shaping hardware was not that flexible a lot of ISPs analysed the traffic and changed shaping routes dynamically which usually reset the shaping for the local ISP network segment (coaxial networks). This resulted in exactly what OP describes.

I was surprised about how a lot of stuff in networking I quickly dismissed at first was actually reality.

Re: Ask HN: Internet magically gets faster when opening speedtest?

#278

Post by wonderbore »

Spooky23 wrote: post #250
zffr wrote: post #218

Earlier quoted context omitted.

I’m not sure why, but I’m seeing 1mbps on fast.com, and 20mbps on speedtest.net. Weird how there’s such a huge difference

T-Mobile and others offer “HD Video” as a premium. So they cap the connection to Netflix to force 720p video.

I'm glad that at least they'd offer 720p as "non-HD", it's not too bad compared to YouTube’s 360p default in Safari iOS. Heck 720p is the limit there.
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