
Fast.com now measures latency and upload speed - kumaranvpl
https://media.netflix.com/en/company-blog/fast-com-now-measures-latency-and-upload-speed
======
headmelted
The problem with this is that Fast.com is owned by Netflix, which is such a
significant consumer of bandwidth that it inclines ISPs to shape traffic to
fudge the numbers. Essentially, this kind of speed test only really tells you
what the maximum bandwidth your ISP is _able_ to provide you is, rather than
what they're really providing. Even then, the test result with Fast.com could
be subject to traffic shaping or slowdown at the _remote_ end, so what is the
result really telling you at all?

In fairness, this would be true of any popular speed test, and I'm not sure of
an obvious solution. Any kind of tunneling or onion routing would render the
test pointless anyway, so I'm not sure of the extent to which you can ever
really trust a speed test of this nature. The only really useful data for this
kind of analysis is likely to come from a router with sufficiently
sophisticated software that it can report on transfer rates over time (which
many do), and even then, that doesn't account for scenarios where the remote
connection is the bottleneck.

~~~
nothrabannosir
That’s a feature, not a bug. It was originally created in the context of the
net neutrality debate. This allows you to see if your ISP is cheating you on
Netflix bandwidth, supposedly in order to push their own media-on-demand
product.

It was introduced after reports of ISPs doing just that, and it was Netflix’
way of hitting back.

~~~
headmelted
Is Netflix sending the video data from Fast.com, though?

If not then they could very well be fudging the numbers for Fast.com and not
Netflix proper.

It may not be common or even legal in the US (I really don't know), but in the
UK traffic shaping is commonplace, even in instances where the package has
been described as "Unlimited".

~~~
nothrabannosir
Yes, open the debug console and see for yourself ;)

    
    
      ...ntflxvideo.net
      ...ntflxvideo.net
      ...ntflxvideo.net
      ...ntflxvideo.net
    

etc.

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kwindla
As a couple of other folks have noted, lots of ISPs prioritize traffic to
(some) known speed test sites, so differing results from different speed tests
-- and results that differ from real world experience -- are pretty common.

Even weirder, sometimes this traffic prioritization happens partly in the
firmware of the modem the ISP provides.

On one of our test network connections, we can reliably trigger a firmware
issue in the router that causes very high packet loss. Then we can "fix" the
issue by visiting www.speedtest.net from any computer on the LAN behind the
modem.

(My company makes in-browser video calling stuff, so we spend a lot of time
worrying about network connectivity.)

And speaking of packet loss, I'd love to see Netflix add a measurement for UDP
packet loss at several throughput levels. There's no easy way for non-
technical users to do a really good packet loss test.

We often get customer support queries that say something like, "My video calls
are terrible but it's not a network issue because I did a speed test and I'm
getting 100Mbs." Which is a totally reasonable thing to say. But when we look
at call data, the person is experiencing regular spikes of, say, 15% packet
loss. That's not something that will effect web browsing noticeably, or even
Netflix video very much, but it makes for really frustrating video calls.

~~~
StudentStuff
Have you tried the DSLReports Speedtest? I've found it very helpful in
diagnosing latent but not obvious network issues:
[https://www.dslreports.com/speedtest](https://www.dslreports.com/speedtest)

------
coatmatter
[https://speedof.me](https://speedof.me) remains my favourite, although I
still find myself using Speedtest at times because that's what everyone else
uses and it's useful to pick a server that others are testing between on any
given day.

Also, there are more links and alternatives under this discussion:
[https://www.reddit.com/r/sysadmin/comments/5mntko/other_alte...](https://www.reddit.com/r/sysadmin/comments/5mntko/other_alternatives_to_speedtestnet/)

Ultimately in most cases, I just want to know whether my connection is working
or not. If it's working, it'll usually be in a certain ballpark. If it's not
(or if I've accidentally left a VPN on), it's obvious.

~~~
woofcat
My problem is that speedof.me seems to be on Amazon EC2 in a US West data
center.

So for me on the East coast it's not really measuring my internet access, it's
measuring my internet access across the whole country.

So using speedof.me I get a result of around 100Mbps.

Using Speedtest.net within my own city it's around 700Mbps.

Using Speakeasy with a Eastern server it's around 400Mbps

speedtest.googlefiber.net to Kansas comes in at around 300Mbps.

So in my opinion the speedtest you should be using is entirely based on who
has servers closest to you physically.

~~~
kalleboo
Ironically, speedof.me is using a server in my country and gets 90 Mbps, and
speedtest.googlefiber.net is using a server in Los Angeles and gets 150 Mbps.
Peering is weird.

I'd love a speedtest that tests to whatever node you're using on all biggest
CDNs (CloudFront, CloudFlare, Akamai, Google, etc)

~~~
pavs
The problem with peering is that cross country peering can cost a lot of
money. So if netflix does not have any caching server in your country, they
will have to pull bandwidth from the closest location and your isp might have
limited peering agreement with that provider.

Which many ISP understansibly will refuse to icrease peering capacity and you
end up with poor bw speed from netflix or other similar providers. The
solution is to do what google does with GGC nodes. Netflix also has similar
service but the are very stringent and picky with which ISP they give the
servers to. Google basically gives them away to almost whoever asks for it.
Not to mention with all streaming and cdn and cloud providers wanting to have
their own ggc like hardware at ISP premise it puts cost strains to isp in
terms of power usage, rack space and high-output switch and routers at the
distribution end. Not to mention all of these hardware will pull bandwidth
from source (about 20%) which will come through ISPs expense.

People often like to blame ISPs. While big ISPs have legitimate problems. It
also makes it extremely difficult for smaller isps bear this cost and provide
service parity compare to ISP giants. Which is why you don't see a lot of isp
business popping up. There is a reason google fibre is so limited in scope.

It always facinates me how most ISPs makes money at all. Then i realize the
one who do has been doing it for a long time ans were already big companies
when started out and probably had to take substantial loans and help from
government and even then it probably took them a long time to be profitable.

~~~
kalleboo
The difficulty in creating an ISP is all in the last mile, not in peering.

Where I live there are 100+ ISPs since there's a national fiber network anyone
can plug into, so to start an ISP all you need is a router and some peering.

~~~
pavs
I was talking about international peering. If you are in USA/Europe, it's not
much of an issue. Outside of that, the situation gets murky. Local ISPs don't
do international peering, they piggyback on other, whose peering capacity is
almost always oversold.

Yes, the last mile is the biggest expense, but other costs are not small
either. An ISP with a couple of 1000 users are just reselling BW from someone
else. They are at the mercy of their upstream's peering. I wasn't referring to
them.

I own an ISP outside the developed nation.

------
abhiminator
This is great!

Fast.com has been my go-to site for speed-tests and sometimes for even
rudimentary connectivity check. It dethroned speedtest.net as my primary
speed-test service for two reasons:

1) I find typing 'fast.com' much easier and hassle-free than typing
speedtest.net (aside from the fact that quick '.com' insertion through
CTRL+Enter shortcut in Firefox makes it even snappier).

2) Netflix's wide _self-run_ server network gives more uniform results,
especially when testing from different continents, because 3rd party server
providers -- in the case of Speedtest.net -- have sub-par performance, imo.

This feature is a welcome addition.

------
reacharavindh
Is there a commandline version of it I can use on a public facing server to
test it's network bandwidth/latency from different parts of the world?

Specific case: Our SSH server accessed by users from all around the world.
It'd be nice to know the bandwidth & latencies our users get.

~~~
marclittlemore
Sindre Sorhus has written a Node wrapper for it which might be useful for you.
[https://github.com/sindresorhus/fast-
cli](https://github.com/sindresorhus/fast-cli)

~~~
Aissen
I've also used Gus Esquivel's go version, it works quite well:

[https://github.com/gesquive/fast-cli](https://github.com/gesquive/fast-cli)

------
iambateman
Well, I'm getting 10-14mbps down from Fast.com and 50mbps down (as advertised)
on speedtest.

Looks like Netflix is indeed being throttled here. What's interesting is that
we haven't noticed any issues with speed while watching netflix.

~~~
jplayer01
What are your speeds on unrelated downloads? Without any other data points,
one could also make the assumption that Speedtest speeds are being fudged by
your ISP, while fast.com is showing your real bandwidth.

~~~
tombh
Which I believe is the whole point of fast.com - to give you a more realistic
measure of your actual bandwidth.

------
mikerg87
Can someone explain the difference between loaded and unloaded latency ?

~~~
tgb
Bufferbloat.net talks about this. The problem is that many home routers do a
poor job allocating their resources so if I'm streaming video and you're
VOIPing, your latency will go up dramatically since my download is pushing you
out. In reality there's enough bandwidth for both of us, but it's getting used
poorly. On my setup, loaded latency was over one second (to google.com)
compared to under 50ms for unloaded! (Fast.com gives more mild numbers for
loaded latency than I observed manually.)

------
observer12
I still say the greatest trick the ISPs ever performed was getting customers
and content providers to both pay. I don't mean simply the content providers
internet bill I mean backbone providers and large orgs like Google and Netflix
paying to connect with an ISP. They double dip already and with net neutrality
gone they can now make even more by charging both for "premium" services on
top of regular charges.

------
Ajedi32
Interesting. When I check the "Measure loaded latency during upload" option my
Loaded Latency value goes up by about two orders of magnitude.

Is there a way to fix this? Seems like there ought to be some sort of traffic
shaping measures I could apply at my firewall (I've got a dedicated box
running pfSense) to ensure low-latency applications get sufficient bandwidth
during upload.

~~~
mastax
This issue is generally called "buffer bloat". That keyword should help you
find solutions. I think it's generally QoS to limit aggregate upload bandwidth
to less than your available so the buffers don't get (over-)filled in the
first place.

------
vladdanilov
Why is it not a browser feature? Transferred 175MB just to measure the speed.
Good it does not do it at 3G speeds.

There are also 156KB of images waiting to be compressed to one third of that
[1].

[1] [https://i.imgur.com/34SWfzo.png](https://i.imgur.com/34SWfzo.png)

------
razster
How come there isn't a speed test site that test closest and furthest away
servers and averages them?

------
XparentX
In Sweden we have ”Bredbandskollem” since around 2007 and with a mobile app
since 2008. Not so many details, but it works. It’s supported by IIS
(Internetstiftelsen I Sverige) which is responsible for .se among other
things.

Fast.com - is 10Mb normal for 4G mobile connection?

------
zkms
Thank you so very much for providing latency-under-load statistics; this is
excellent.

------
dsr_
Interesting point: fast.com prefers my IPv6 connection, which is through a
Hurricane Electric tunnel that Netflix won't serve. As a diagnostic for
Netflix, that makes this useless.

~~~
detaro
It measures the speed against actual Netflix CDN servers, so how can it
"prefer your IPv6 connection" for the speed measurement?

~~~
dsr_
I have IPv4 from my ISP, and a Hurricane Electric tunnel to provide IPv6,
because my ISP is lame. (Hello, Verizon FIOS.)

Netflix prefers IPv6. However, they have blacklisted the Hurricane Electric
endpoints, because their paying customers with valid accounts might use those
endpoints to view the content that they paid for while sitting in another
country.

The blacklist does not take effect until you try to actually get video content
from Netflix, at which point an error is returned.

The result of all this is that fast.com measures the speed of my IPv6 tunnel
to Netflix CDN servers, which will not serve content. I have to turn off IPv6
routing on boxes in my house that want to watch Netflix, and then it falls
back to IPv4... a completely different path than the one fast.com has just
measured.

~~~
detaro
Oh, interesting failure case.

------
madspindel
Awesome! But they should add PWA support so you can add it to iOS home screen.

~~~
1123581321
You already can in the share sheet. I have had it on my home screen for a
couple years. It has the right kind of icon, too.

------
lazharichir
Works great!
[https://cdn.pbrd.co/images/HuZPvRU.png](https://cdn.pbrd.co/images/HuZPvRU.png)

------
ulfw
So then it’s like Ookla Speedtest?

~~~
taspeotis
Some ISPs might prioritize traffic to Ookla (or its mirrors) which makes the
ISP look better than they really are.

With FAST.com you can see if your ISP throttles traffic to Netflix in any way,
which is desirable for the ISP but undesirable for you.

~~~
ulfw
Cool. So fast.com can't have traffic prioritised to it's domain? Shouldn't it
better be fast.netflix.com or something?

~~~
badwolf
fast.com uses video data from ntflxvideo.net

~~~
ulfw
Great. That makes sense then. Thank you!

------
sz4kerto
Except fast.com doesn't as many locations as speedtest.net; so the best I can
get with fast.com is ~250 Mbps, while speedtest.net measures 900 Mbps.

~~~
alphabettsy
Idk if you noticed, but with Speedtest.net often times you’re testing against
an ISP-run or sponsored server so it’s hardly an accurate portrait of speeds
with a typical service.

~~~
magicalhippo
But you can select servers yourself. So I usually use the auto-selected server
(sitting at my ISP or similar) to check local conditions such as is my cable
modem or router/firewall doing fine or not. If I want to test "usable"
bandwidth, I'll select a few servers in other, far-away cities like Amsterdam,
Miami etc.

