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Standard User jcw
(regular) Sat 08-Mar-14 21:20:13
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ADSL2+ IP Profile problem


[link to this post]
 
My line was upgraded to 21CN ADSL2+ on 14/2. The day prior I was happily connected at 6688 Kbps on ADSLMax, with a 5.5 Mbps IP profile (happy days).

Following switchover, the SNR target was immediately raised to 9dB, then rose to 12dB, but has steadily dropped since. Earlier this week, it dropped to 3dB, which is stupid for my line length, but there goes to magic of DLM.

The problem I have is that at some point on 18/2 I noticed I was getting a reduced actual download speed, and ran a test on BTW's performance test site. I was surprised to see that the full test results reported:

Download speed achieved during the test was - 4.31 Mbps
For your connection, the acceptable range of speeds is 1.2 Mbps-4 Mbps.
IP Profile for your line is - 3.78 Mbps

This with a downstream connection rate of 6432 Kbps.

At no point since 18/2 has the IP profile rate or the acceptable speed range changed. It is still the same at the time of writing.

The line connection rate is simply not reflecting an IP Profile of 88.2% of the connection speed - which it was from 14-18/2.

My ISP seems to have drawn a blank/given up, and simply cannot offer any explanation as to what is going on. Has anyone seen anything similar or got any advice as to what to do next?
Standard User Zarjaz
(knowledge is power) Sat 08-Mar-14 21:24:44
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Re: ADSL2+ IP Profile problem


[re: jcw] [link to this post]
 
What are you line stats, and have you done the obvious, and plugged in to the test socket to see what stats that then produces ?

Standard User jcw
(regular) Sat 08-Mar-14 21:34:03
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Re: ADSL2+ IP Profile problem


[re: Zarjaz] [link to this post]
 
Yes - done all that.

The issue is that from having a line that performed rather nicely, I now have one that appears to be "capped" in some way.

Downstream connection 6432 Kbps should equate to an ADSL2 IP profile of 5.67 Mbps, not 3.78 Mbps as reported by BTW. And if BTW is right, and my IP profile is 3.78 Mbps, why am I able to download at 4.3 Mbps?

For four days the IP profile was exactly 88.2% of the connection rate, as I would have expected. Since 18/2 it has not been anywhere near, and actual download speeds range from 4.1-4.3 Mbps


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Standard User RobertoS
(sensei) Sat 08-Mar-14 22:01:06
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Re: ADSL2+ IP Profile problem


[re: jcw] [link to this post]
 
Which ISP is it?

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 59.4/14.4Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User jcw
(regular) Sat 08-Mar-14 22:11:56
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Re: ADSL2+ IP Profile problem


[re: RobertoS] [link to this post]
 
Eclipse
Standard User RobertoS
(sensei) Sat 08-Mar-14 22:26:25
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Re: ADSL2+ IP Profile problem


[re: jcw] [link to this post]
 
The BT IP Profile is held at two places if not more, and these can get out of step. One is the BRAS, the other is the MSAN. Presumably one is a copy of the other and the copy routine failed the last time it changed.

This came to light a few years ago when the system Plusnet run of also holding a copy themselves (a system where their copying is known to fail frequently) looked correct as it agreed with the value reported by the BT speed test, but the throughput was clearly more restricted.

They ran some other test that showed "an imbalance in the BTW system". You seem to have the opposite effect, as you can exceed the reported IP Profile. It might be worthwhile asking them about this test they can run. I'm sorry, off-hand I don't know its name frown.

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 59.4/14.4Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User jcw
(regular) Sun 09-Mar-14 10:56:11
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Re: ADSL2+ IP Profile problem


[re: jcw] [link to this post]
 
This is the kind of performance I am getting.

The HTTP test shows that, at burst, the line is capable, albeit briefly, of actually getting to a speed commensurate with my actual connection rate - which is 6,647 Kbps right now.



Test result
Administrator MrSaffron
(staff) Sun 09-Mar-14 12:20:02
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Re: ADSL2+ IP Profile problem


[re: jcw] [link to this post]
 
Posting the link to the result will help people to understand and whether the burst looks like software induced or maybe is representative of what the connection can do

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User jcw
(regular) Sun 09-Mar-14 13:00:43
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Re: ADSL2+ IP Profile problem


[re: MrSaffron] [link to this post]
 
I thought I had! :/

http://www.thinkbroadband.com/speedtest/results.html...
Standard User jcw
(regular) Sun 09-Mar-14 14:12:57
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Re: ADSL2+ IP Profile problem


[re: jcw] [link to this post]
 
Here is another one, just to be sure.....

http://www.thinkbroadband.com/speedtest/results.html...
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