ADSL2+ IP Profile problem

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?

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 ?

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

Which ISP is it?

Eclipse

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 .

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

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

I thought I had! :/

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

Here is another one, just to be sure.....

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

You did but in between gardening I missed the original link.

Notice the dip before the peak, suggests something may be caching the data then passing it onto the flash tester, rather than being a real throughput result.

The line looks to be running at around the 4 Mbps throughput area. We include the burst because that is what some other testers actually report

Yes - 4Mpbs is exactly what the line has consistently been running at - no dispute there.

My issue is that the line sync is 6,647 Kbps. The BTW performance tester reports similar download speeds to the TBBtest. However, it also says that my line is only capable of 4Mpbs and that my IP Profile is 3.78 Mbps.

As I am now on ADSL2 the BTW reported IP Profile is 56.87% of the actual connection speed, as opposed to 88.2% as one would expect. Prior to being moved to 21CN, the ADSLMax connection had an IP profile of 5.5 Mbps, and after conversion on 14/2 the test results were totally consistent with the 88.2% theorem. On 18/2 the test results suddenly started indicating that the best I could achieve was 4 Mbps, even though the actual speed exceeds this.

For years on ADSLMax I have had a better line speed/IP Profile than this - on 18/2 this all changed.

I suspect a BT systems IP Profile mismatch, but have no idea how to take it further.....

ISP listens, ISP understands, ISP puts in request for a DLM reset to get the BT Wholesale side to relearn everything which should trigger the IP profile too.

In the past some have found a deliberately slow sync will force IP profile down and then a normal one will get it back to the correct value, but that was more on the old 20CN system

They did a full reset last Monday. All it did was lift the SNR target from 3dB (stupidly slow for my line) to 6dB. Nothing else changed. They said BT were going to manually rebuild the circuit on Tuesday, but I remain unconvinced that ever happened as there wasn't even a loss of sync. Now they say they cannot do anything more other than get an engineer out, but that probably won't help.

It's a ridiculous situation........

In between gardening too (well, cleaning nest boxes actually), I have now forced a very low sync.

Line stats:

Rx Sync: 506 Kbps
Rx Noise: 33.4 dB
Rx Atten: 52.5 dB

TBB test result http://www.thinkbroadband.com/speedtest/results.html...

However, the corresponding BTW Performance Test result is largely unchanged (and I did the test after I did the TBB one):

Download speed achieved during the test was - 0.45 Mbps
For your connection, the acceptable range of speeds is 1.2 Mbps-4 Mbps.
IP Profile for your line is - 3.78 Mbps

Something stinks methinks.....

Really appreciate any thoughts, as the BTW IP Profile simply doesn't change.....

It gets better. Now the BTW Performance Tester wants to do a TAP3 test, asks me to log in as speedtest@speedtest_domain and then fails.....

In reply to a post by jcw:

Now the BTW Performance Tester wants to do a TAP3 test, asks me to log in as speedtest@speedtest_domain and then fails.....

I've been getting that. Decided it looked fishy so did some checking, with interesting results.

Noted the url of the TAP3 test server, then pinged it whilst logged in to the speedtest domain. Result- Host not found.

Log back in to my ISP and repeat the ping- IP address returned and Request timeout.

Back in to the speedtest domain and ping the IP address- Request timeout.

In other words, BT can't even set their own DNS up properly� and they're in charge of the nation's internet links

Which ties in with what I was saying. The reported IP Profile, which continues to be stuck, isn't the one that is actually applied to the line.

This may sound silly but has the original poster verified the number that their line is seen as, i.e. call their mobile and check the number matches the voice line billing

Beyond that it is possible that BT Wholesale has somehow borked the records for the line with regards to wholesale. A lift and shift which would cause the line to drop while it was being shifted would fix problem, i.e. issue may be a duff line card port and moving line on DSLAM will also ensure a rebuild for the line records in the various databases

You might be on to something there ....

It is more than likely that if the OP's circuit was upgraded to 21cn as part of a bulk migration, it could be on the wrong port .....

ah, 'cept of course his login would be rejected wouldn't it ?

If the login was for another account with the same part after the @ then it would still authenticate, or in the old days it was not impossible for the odd port to appear to not have the authentication limited to a specific domain

It's definitely the right number - checked both calling from it and using 17070

The issue didn't arise on the day the 21CN switch took place - it was four days later

Edited by deleted (Sun 09-Mar-14 19:11:29)

So, now my request to be moved back to an ADSL1 profile has been actioned, and lo and behold the results are suddenly very different:

TBB test result

However, the BTW performance tester still reports an erroneous IP Profile, and reports a download speed of 5.54 Mbps against a profile of 5.17 Mbps (which does not change with an change in sync)

Does this provide any clues to where the problem lies - other than within the BT system somewhere.

BT continue to maintain that they completed a 'cease and reprovide', but I simply cannot see how this was managed without a loss of sync at any stage!

Line currently synced at 6400 Kbps down.