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How can I determine if my speedtest server is accurate

Posted on 2011-10-25
Medium Priority
Last Modified: 2012-05-12
We are using software from Ookla.  Doing a speedtest from within a LAN, say at any workstation we get skewed results.  

Bandwidth T-1
Speedtest results:    1.40 down and 768k up

My question is shouldnt these results be symmetrical?  Would the LAN in any way get in the way of the results and if it did should that not bring down the total bandwidth reading symmetrically?

Question by:marchopkins
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LVL 46

Expert Comment

by:Kent Olsen
ID: 37027613
Hi March,

It's not uncommon for networks to have different upload/download speeds.  The traffic is directional and it's fairly easy to have a network device send at one speed and receive at another.  Many ISPs do that.  Your home connection may well be 8Mb download, but only .5Mb upload.

Good Luck,

Author Comment

ID: 37027805
I understand that, but let me ask this just to further clarify.  Can LAN traffic effect the speedtest in any way?

LVL 11

Expert Comment

ID: 37027948
  The answer is yes. I have called different ISPs on several occassions to question the speed and before they will even talk about they want you to disconnect the router from the LAN and plug it in to a single computer off the LAN and test the speed. LAN traffic does effect the speedtest results.
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LVL 20

Assisted Solution

edster9999 earned 248 total points
ID: 37030206
It will do, but it should be a small amount.
If there is a big difference between the speed throught he LAN and the speed when you plug in direct to the Internet feed then you should look intoyour local network to make sure your hubs/switches have enough speed and capacity to handle the on going traffic.

Also repeat the test a few times - data can be skewed by someone or something else slowing the link down.

LVL 19

Accepted Solution

xterm earned 504 total points
ID: 37032191
I'm going to disagree with the others here.  We run Ookla as well here and if you are on a T1 link you should get approximately 1.5 mbps in BOTH directions.

That will heavily depend on mutiple variables:
1)  The amount of activity/load on the Speed test server
2)  The amount of activity/load on the client workstation
3)  The amount of bandwidth activity on the network segment between client and server

That being said, regardless of where a degradation occurs, you should see a symmetric drop in performance on both up and download, UNLESS your segment is unduly loaded in one of those directions.  But even in that instance, the discrepancy shouldn't be as large as you saw because if your upload is pegged, download would suffer heavily too (TCP downloads rely on uploading acks to the remote server to tell it to send more data down, and vice versa.)

Thus my contention is that if you are not getting symmetrical speedtest results & none of the factors above apply to you, you are not being provided the speeds you are paying for.

BTW, you never did say - is your client workstation on one end of a T1, and the Ookla server on the other?
LVL 11

Assisted Solution

jimbecher earned 248 total points
ID: 37032654
  I am going to agree to disagree. I am first going to go back to my original point that no matter which ISP you call about speed issues the first thing they want you to do is disconnect the internet from the LAN and run the speed test directly from one computer and it must be the only computer connected to the internet. Right there tells you that even the ISP know LAN traffic does interfere with bandwidth results.

   That is about the only way to get a accurate bandwidth measurement. Even then tests will vary depending on which speedtest you use and how far away you are from that site. As a rule most people and ISPs I have come across agree that speakeasy.net is one of the better ones but even they have problems. If you go to speakeasy,net and test from Chicago your results will very greatly as opposed to testing from San Francisco. You can use different speedtest sites but to compare apples to apples the test sites should be located in roughly the same geographic area.

   Unduley loaded in one direction? Yes. Possible. I got a call from a customer just the other day with the exact same issue. Good download but the upload was horrid. Turned out MuTorrent was running on one workstation and had seeded and was uploading 5 different torrents. He killed MuTorrent and his speedtest was fairly accurate. It does happen.

   In my case I have FIOS. 35/35. I hit speakeasy and only showed 20 down. Came to find out that it was a problem with speakeasy not being able to handle that great of a download speed. Bandwidth test can only give you a general idea of what you are getting. There are way too many variables that come in to play to consider it accurate. Test site location, test site itself, LAN traffic, you name it. All you can do is "interpret" the results.

   Looking at your results your download looks OK. There is something going on with the upload. The results will never be dead nuts symmetrical but in looking at your results you definitely either have something going on from the LAN or your ISP is cheating you.

   I would start with what the ISPs usually recommend. Unplug the internet from the LAN and plug it in to one and only one computer. Then use a couple different test sites. It should open your eyes to what is going on.
LVL 19

Assisted Solution

xterm earned 504 total points
ID: 37032760
I run an ISP, so I know what ISPs ask for and why (as so it sounds, do you).  Removing other variables is troubleshooting 101 and there's no doubt that LAN traffic has the ability to affect bandwidth results, but my contention is that it should do it symmetrically, and it sounds like you later say pretty much the same thing in your post, so perhaps you're actually agreeing to agree.

Author Closing Comment

ID: 37083000
thanks guys.  I better understand this now.  I agree with a piece of what you are all saying.  I do disconnect LAN traffic and run from the back of an IAD out to the speedtest server at network's edge.   Its the only way i can be assured that I have an accurate measurement.

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