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Re: Affect on speeds of the Plusnet profile

Community Veteran
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Registered: 10-06-2010

Re: Affect on speeds of the Plusnet profile

I've started a plan to re-test the issue myself. Because I can't just directly change the plusnet profile myself, I'll have to:
1. increase my line speed
2. wait for plusnet profile to increase
3. decrease my line speed
4. measure the throughput before the plusnet profile decreases
So far I have succeeded with step 1, and have been waiting for step 2, which is guaranteed to happen in a timely and reliable manner (hashtag sarcasm). An unexpected by-product of the experiment so far is that my line seems adequately stable at the higher speed.
[tt]US Connection Rate:    882    DS Connection Rate:    4019
DS Line Attenuation:    57.9    DS Margin:              6.1
US Line Attenuation:    36.3    US Margin:              5.2[/tt]
30 REPLIES
Community Veteran
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Re: Affect on speeds of the Plusnet profile

So I finally got around to doing the test:
PN profile 3.5
sync 4059
throughput 403KiB/s - 158385999 bytes in 6m 23s
PN profile 3.5
sync 3739
throughput 392KB/s - 158385999 bytes in 6m 34s
I was downloading firefox-28.0-3.fc20.src.rpm with wget.
I didn't do some worthless ping test at the same time because that would be completely missing the point of this thread - that the PN profile seems to limit my speed to less than what the line is evidently capable of. Also because I don't particularly care about the performance of ICMP echo requests and replies.
eblakeborough
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Registered: 11-08-2012

Re: Affect on speeds of the Plusnet profile

Based on those sync rates, that profile is the correct profile by the way.
Your ip profile is always 88.2% of your sync rate. our profile matches BT's (the majority of the time)
On the second one the profile hasn't updated yet.
Community Veteran
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Re: Affect on speeds of the Plusnet profile

Quote from: Ed
On the second one the profile hasn't updated yet.

Yes that was the whole idea of those measurements. I'm waiting to do the third test, once the Plusnet profile updates to 3.2. Then the throughput won't be the line speed of 392KiB/s, it will go down to I expect about 360KiB/s. The Plusnet profile may be set to the same number as the BTWholesale profile, but its affect on the speed is not the same.
392KiB/s is approximately 3.21Mbit/s which is just under the BTWholesale 88.2% IP profile for the sync speed of 3739.
Perhaps not all the layers of protocols encapsulated within other protocols are not being accounted for correctly when applying the PN profile, or perhaps Plusnet just decide to knock 5% off all ADSL customers' speeds to reduce Plusnet's bandwidth requirements in the hope people won't notice the slight discrepancy.
Community Veteran
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Re: Affect on speeds of the Plusnet profile

The PN profile eventually updates, so I can do the third test.
PN profile 3.5
Limited by PN profile: yes
sync 4059
throughput 403KiB/s - 158385999 bytes in 6m 23s (3.308Mbit/s)
PN profile 3.5
Limited by PN profile: no
sync 3739
throughput 392KB/s - 158385999 bytes in 6m 34s (3.216Mbit/s)
PN profile 3.2
Limited by PN profile: yes
sync 3739
throughput 368KiB/s - 158385999 bytes in 7m 0s (3.017Mbit/s)
Not quite as bad as I thought but the difference is still greater than the 100Kb rounding margin given. So, why can't the PN profile limit the speed to what the line is actually capable of? How do you get away with calling it Unlimited broadband?
And it's going to be difficult to try to explain away the difference by arguing that the speedtester is measuring the speed wrong, since I didn't use a speedtest website, so unless you are going to try to argue that it didn't actually take wget 26 seconds longer to download the same file. Perhaps a load of good sounding but meaningless technical gibberish about protocol overheads, which are exactly the same for all of the three measurements? Oh dear, I did all the tests over wireless, perhaps you would like to blame the wireless?
Plusnet Alumni (retired) chrispurvey
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Re: Affect on speeds of the Plusnet profile

Quote from: ejs
How do you get away with calling it Unlimited broadband?

It's Unlimited due to no usage restrictions not speed.
The PN profile eventually updates, so I can do the third test.
Quote
PN profile 3.5
Limited by PN profile: yes
sync 4059
throughput 403KiB/s - 158385999 bytes in 6m 23s (3.308Mbit/s)
PN profile 3.5
Limited by PN profile: no
sync 3739
throughput 392KB/s - 158385999 bytes in 6m 34s (3.216Mbit/s)
PN profile 3.2
Limited by PN profile: yes
sync 3739
throughput 368KiB/s - 158385999 bytes in 7m 0s (3.017Mbit/s)
Not quite as bad as I thought but the difference is still greater than the 100Kb rounding margin given. So, why can't the PN profile limit the speed to what the line is actually capable of?
And it's going to be difficult to try to explain away the difference by arguing that the speedtester is measuring the speed wrong, since I didn't use a speedtest website, so unless you are going to try to argue that it didn't actually take wget 26 seconds longer to download the same file. Perhaps a load of good sounding but meaningless technical gibberish about protocol overheads, which are exactly the same for all of the three measurements?

I'll flag this up with Dave, he's not in today though.
Quote
Oh dear, I did all the tests over wireless, perhaps you would like to blame the wireless?

Regardless, it is always more accurate over a wired connection.
Plusnet Alumni (retired) chrispurvey
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Posts: 5,369
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Re: Affect on speeds of the Plusnet profile

Can you try those downloads again as you're on one of the recently added gateways and we can see if there's a difference?
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Re: Affect on speeds of the Plusnet profile

Quote from: Chris
Quote from: ejs
How do you get away with calling it Unlimited broadband?

It's Unlimited due to no usage restrictions not speed.

Even that is factually incorrect. Calling it "Unlimited Broadband" requires both speeds and usage to have no restrictions.
I can't do another test right now, probably the next convenient time will be early tomorrow morning, plus I already put by sync speed back up.
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Re: Affect on speeds of the Plusnet profile

I don't know what gateway I was on when I did the test early this morning, I did not record it, although I was on ptn-bng01 shortly afterwards when I posted the results on the forum.
After reconnecting and ending up on pcl-ag02, I saw that the previous file download was not running at a completely maximum speed 100% of the time, so I had to download something else that did.
[tt]wget http://download.microsoft.com/download/6/E/F/6EFA2958-EF2B-4DD1-B3BC-B891CB7C83DC/Windows6.0-KB94782...
--2014-04-16 21:34:50--  http://download.microsoft.com/download/6/E/F/6EFA2958-EF2B-4DD1-B3BC-B891CB7C83DC/Windows6.0-KB94782...
Resolving download.microsoft.com... 23.61.255.25, 23.61.255.17
Connecting to download.microsoft.com|23.61.255.25|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 150518130 (144M) [application/octet-stream]
Saving to: ‘Windows6.0-KB947821-v33-x86.msu’
100%[======================================>] 150,518,130  370KB/s  in 6m 38s
2014-04-16 21:41:28 (369 KB/s) - ‘Windows6.0-KB947821-v33-x86.msu’ saved [150518130/150518130][/tt]
I was not planning to mess about testing every single gateway, moving my sync speed up or down, and then waiting a few days for my PN profile to go up or down. And I already reproduced the same thing back in August 2013, which presumably pre-dates your new gateway.
Community Veteran
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Registered: 10-06-2010

Re: Affect on speeds of the Plusnet profile

Well apparently I got kicked off pcl-ag02 at about 22:47, so when I re-tested the download speed this morning I noticed a tiny difference, and then saw that I'm now on ptw-bng01
[tt]--2014-04-17 06:42:26--  http://www.mirrorservice.org/sites/dl.fedoraproject.org/pub/fedora/linux/updates/20/SRPMS/firefox-28...
Resolving www.mirrorservice.org... 212.219.56.184
Connecting to www.mirrorservice.org|212.219.56.184|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 158385999 (151M) [application/x-redhat-package-manager]
Saving to: ‘firefox-28.0-3.fc20.src.rpm’
100%[======================================>] 158,385,999  366KB/s  in 7m 2s 
2014-04-17 06:49:29 (367 KB/s) - ‘firefox-28.0-3.fc20.src.rpm’ saved [158385999/158385999]
--2014-04-17 06:49:37--  http://download.microsoft.com/download/6/E/F/6EFA2958-EF2B-4DD1-B3BC-B891CB7C83DC/Windows6.0-KB94782...
Resolving download.microsoft.com... 23.61.255.25, 23.61.255.17
Connecting to download.microsoft.com|23.61.255.25|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 150518130 (144M) [application/octet-stream]
Saving to: ‘Windows6.0-KB947821-v33-x86.msu’
100%[======================================>] 150,518,130  366KB/s  in 6m 41s
2014-04-17 06:56:19 (366 KB/s) - ‘Windows6.0-KB947821-v33-x86.msu’ saved [150518130/150518130][/tt]
And I watched those downloads to check they ran at full speed the whole time, which they did. I conclude the difference between gateways so small that it is only just measurable and cannot possible account for the at least 22 KiB/s lost due to the PN profile.
Community Gaffer
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Re: Affect on speeds of the Plusnet profile

EJS:  Feel free to bite my head off, but I'm wondering if it might make sense to start a new thread with your test results so far on this.  I really want to get to the bottom of this, but there a lot of noise on this thread, and with a new one, we could ask the mods to be quite aggressive about keeping it on topic. 
Kelly Dorset
Broadband Service Manager
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Re: Affect on speeds of the Plusnet profile

@ejs
If you want to start this in a new thread it might be better to split off the relevant posts from here
If you can advise the ones you would like splitting off either in this thread or by PM I will do it
Community Veteran
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Re: Affect on speeds of the Plusnet profile

I supposed it would make sense to split off replies 65, 69, 70, 74, then 77 onwards to a new thread.
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Re: Affect on speeds of the Plusnet profile

Done
If you would like the title changing please advise
I might add that this thread brings everything back to my first post in the original thread - and no I am not going to try to sort it out
Quote from: Oldjim
Why does the Plusnet profile knock so much off the line speed
Example
Sync 4,000kbps BT IP profile 3,528kbps Plusnet profile 4,100kbps

Sync 4,000kbps BT IP profile 3,528kbps Plusnet profile 3,500kbps

I don't want some anodyne answer I want a proper explanation and a reason why it can't be fixed
Community Veteran
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Re: Affect on speeds of the Plusnet profile

I suppose I should approximately add the TCP and IP headers in an attempt to make the numbers more readily comparable to the IP profiles. Each IP packet has a 20 byte IP header, a 20 byte TCP header and up to 1460 bytes of payload data. 158385999/1460 = 108484 IP packets. 158385999+(108484*40) = 162725359 bytes including the TCP and IP headers. That makes the results:
PN profile 3.5
Limited by PN profile: yes
sync 4059
IP layer: 162725359 bytes in 6m 23s = 3.399 Mbit/s
PN profile 3.5
Limited by PN profile: no
sync 3739 (88.2% gives BT Profile of 3.297 Mbit/s)
IP layer: 162725359 bytes in 6m 34s = 3.304 Mbit/s
PN profile 3.2
Limited by PN profile: yes
sync 3739
IP layer: 162725359 bytes in 7m 0s = 3.100 Mbit/s
Those figures look almost as if the plusnet profile is the BT profile, rounded down to the nearest 100k, and then has 100k subtracted.
(I also just looked at some of the statistics in wireshark, but wireshark indicated 164244640 bytes which looks like it was including the 14 byte ethernet layer on each packet.)