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Hazy Arc

Greenwood, SC
·Embarq Now Centu..

4 edits

[Embarq] Speedtest Curiosity

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Centurylink Hosted
Just for kicks, let's try a little experiment. Head over to »www.speedtest.net and give your connection a few tests - heck, choose several different server locations if you're feeling adventurous. When given the ability to share your results, copy/paste the URL to the test here.

Next, head over to »speedtest.centurylink.net/ and give that one a whirl and post your results.

Interestingly enough, the "Centurylink" hosted speedtest tells a totally different story than the ones hosted externally on Speedtest.net.

On my 10/896 connection, here's what Speedtest.net says I have during the evening:

»www.speedtest.net/result/2453118 ··· 8996.png
»www.speedtest.net/result/2453119 ··· 9637.png
»www.speedtest.net/result/2453120 ··· 0376.png

I've attached my CenturyLink hosted test that was done right after the Speedtest.net ones. I'd imagine Centurylink tells users to use their "official" speedtest, which is a crock of crap and is probably hosted at their headend, thus doesn't give a true picture of actual internet bandwidth. My "ground truth" web browsing and file downloading lends more credence to the slower Speedtest.net ones. What say you guys?


You have to understand what is being tested. Both tests are valid but they test different things. The Centurylink test shows what you are capable of getting. This would be useful for figuring out what your speed to another Centurylink hosted customer would be, or what you could get total while downloading from multiple sites in different parts of the internet. An external site would be more indicative of a download from a single site hosted elsewhere, taking into account congestion that occurs either within or outside of Centurylink's control. If there's a significant difference, the problem may or may not be fixable by Centurylink. If they're the same and you're too low, the problem is probably in your line. Also keep in mind that different test servers in different parts of the country are going to give different results.

For the record, the Centurylink test and a test to the DSLReports Megapath server in LA gave me about the same results. A test to the DSLReports Comcast server in Denver was much lower. Your results will likely vary.

Hazy Arc

Greenwood, SC
·Embarq Now Centu..
By that logic, the problem isn't my line then - as I maintain a consistent 11-13 Mbps according to Centurylink's speed test.

I'd argue that knowing my connection speed to another Centurylink customer is an effectively useless statistic. What good is paying for a 10Mbps connection when I can't even attain those speeds outside of CenturyLink's internal network?


Olathe, KS
reply to Hazy Arc
For those wondering how the workings of Centurylink's speedtest works compared to speedtest.net stuff.. it's the same.

Only difference is... CenturyLink speedtest is [mostly] on the network of Centurylink routing.
Here's a trace to the Chicago, IL to the .182 IP.

Now, let's do a test on a speedtest.net server - just to see what the internet does to it.

So, I used the server in chicago, IL, hosted by Towerstream. Let's have a peek at the routing currently going on with this...

Well, erm.. uhh.. well, definately no longer on CenturyLinks' backbone or network after hop seven. Something else happened as well, to a server that is also in Chicago, IL, I am going from Kansas City to Dallas, TX, over to Chicago, IL. Quite the nice little trip i take there.

So in the end, what am i getting at? CenturyLinks speedtest sites are [mostly] on the CenturyLink/Qwest backbone. Where as sites as seen on speedtest.net are not on the same backbone. What can this cause? some speed test sites via speedtest.net will have highly variable results. Whereas some will report highly innaccurate numbers, and some will report tests that are on the spot. CL's speedtest servers remain within the network of centurylink, which means lesser routes to the destination, lesser chance for hops to escape the network, which in the end means better chance for network engineering at CL to identify issues within their network.

TL;DR; don't rely on a single speedtest to get a quick result. Use multiple sites/servers to get your averages and numbers. :D


Springfield, MO
The local CenturyLink CO is where the speedtest for the location is hosted. They're all Ookla licensed applications - same as Speedtest.net. Some of the sites don't even work properly..

It's not the best test for testing normal use.


reply to Hazy Arc
my ping was much worse on the CL site but speeds were better