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Plusnet speedtest accuracy - London-Sheffield link overload?

Community Veteran
Posts: 26,357
Thanks: 607
Fixes: 8
Registered: 10-04-2007

Plusnet speedtest accuracy - London-Sheffield link overload?

Today I've had cause to consider the accuracy of the Plusnet speed tester. In a short space of time I ran a number of tests using the Plusnet tester and the ADSLGuide tester, interleaving the tests to each.

The average speeds obtained from the tests:

Plusnet: 4823

ADSLGuide: 5536

Interestingly the fastest result obtained was on a Plusnet test (6026.9), however Plusnet also gave me results of 3381.9 and 3892.3. It appears that something is causing wild variations in the Plusnet test results.

Plusnet's tester runs from the portal servers - which are located in Sheffield so I'm wondering if the 155MB London Sheffield link is overloaded (for anyone not familiar with the Plusnet network arrangement a diagram can be found here). This same link will be carrying all the spam emails coming in the Plusnet from the rest of the internet that we have been told are causing the email slowdowns.

Apart from the affects of the traffic, the ping times to the Sheffield servers are noticeably higher than to the London servers (and ADSLGuide!). I've checked the pings to various Plusnet servers and other speed test servers - here are the averages of 10 pings to each:
Server                      Min   Max  Average


portal.plus.net 19ms 22ms 20ms
mail.plus.net 19ms 22ms 20ms
relay.plus.net 19ms 23ms 20ms
usergroup.plus.net 20ms 22ms 20ms
imap.plus.net 19ms 21ms 20ms
homepages.plus.net 19ms 22ms 19ms
ftp.plus.net 18ms 23ms 19ms
usenet.plus.net 10ms 12ms 11ms
ccgi.plus.net 10ms 13ms 11ms
frontpage.plus.net 20ms 25ms 22ms
humbug.plus.net 11ms 12ms 11ms

www.adslguide.org.uk 11ms 13ms 11ms
www.dslzoneuk.net 11ms 15ms 12ms
www.speedtest.bbmax.co.uk 12ms 13ms 12ms
www.kbps.co.uk 10ms 14ms 11ms


Questions:

1. Is the London/Sheffield link overloaded?

2. Is this the reason why portal pages sometimes take ages to come up and email collection occasionly times out?

3. Why isn't the speedtest on a London based server so that we are testing our link and not testing the London/Sheffield link as well?
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
2 REPLIES
N/A

Plusnet speedtest accuracy - London-Sheffield link overload?

I've found the same thing in the (recent) past, higher speeds on ADSLGuide and other testing tools compared with Plus's. Strange as you would expect the reverse.

Jay
Community Veteran
Posts: 26,357
Thanks: 607
Fixes: 8
Registered: 10-04-2007

Plusnet speedtest accuracy - London-Sheffield link overload?

The test results I get from ADSLGuide and the other testers are remarkably consistent while the Plusnet test I think is useless given the inconsistency in the results it produces.

I would think that a lot of people will be looking at their speeds after upgrading to MaxDSL and will be using the Plusnet tester - if the speed reported by this can be over 40% below the correct figure I wonder how many extra questions are being opened.

As the figures I gave demonstrated, the London based Plusnet servers (usenet, ccgi, frontpage and the mySQL servers) give very similar pings to the common used other speed testers whilst the Sheffield servers give significantly worse pings.

I completely fail to understand why the speed test tool does not run on a London server so that we are testing our link alone and the results are not affected by whatever is happening on the London/Sheffield link.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)