Unresolved support ticket open for more than six months - is this a record?

[#1]

Just tried rebooting the router and I now have a synch rate of 6176kbps with SNR margin=5.5. I can't do another BT speed test for another hour, but the Thinkbroadband speed test shows download speed at around 725kbps. This is typical behaviour i.e. I expect to be disconnected after a few hours and the synch rate drop back down to around 1000kbps or less - this is what happens when BT engineers visit as well...
I've kept Routerstats running to see if this can trap what's happening when I get a disconnection.
Will post the BT speed test results later. I've updated the support ticket as well.

[#2]

I couldn't do a BT Speed test last night as the server was unavailable, but a test at 05:49 this morning revealed the following:-
Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 6240 kbps(DOWN-STREAM),  448 kbps(UP-STREAM)
    IP profile for your line is - 5500 kbps
    Actual IP throughput achieved during the test was - 4504 kbps
Which is not really what I was expecting! This has happened once before i.e. last week, I rebooted the router on 7th Jan (at 18:02) and obtained a synch rate of 4768kbps and a throughput of 3661kbps. This lasted until Friday (9th) when the throughput dropped to 1821kpbs. And on Saturday morning, the synch rate dropped as well (to 2944) and throughput increased to 2369. However, on Sunday morning, the synch rate had increased to 6048, but throughput had increased to a whopping 4752 - the fastest I've ever seen at this property! But it didn't last - the router was disconnected at 17:02 (on Sunday) and synch rate dropped to 1056 on reconnection - throughput was back to a measly 700kps. This lower performance lasted until this morning. SNR margin has been consistently around the 5.5 and 6.0 mark, but it did reach 8.5Db when I had the fastest speed (4752) last Sunday (11th).
The router was disconnected about 23:25 last night so that explains the resynch, but not the sudden increase in speed. I'll leave my pc on today, with Routerstats running, to see if anything else is highlighted.

[#3]

Hi Catweazle,
The increase in speed is entirely down to the fact that your IP Profile has increased because you were able to keep the higher level of sync.
Hopefully it stays that way!

[#4]

Thanks, James - I know the actual download speed increased due to the higher IP profile, but I was querying what caused the line to resynch at a higher speed in the first place. As I said yesterday, this has happened once before (last week) but most days over the last weeks and months the router has only be able to synch at around 1000kbps. I certainly haven't changed anything, so what's caused the improvement? I'm not complaining about the increased speed (which is great!), I'm just concerned that it will drop again and we'll all be none the wiser as to what caused the problem in the first place.
Latest BT speed test results are still good, as shown below:-
Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 6240 kbps(DOWN-STREAM),  448 kbps(UP-STREAM)
    IP profile for your line is - 5500 kbps
    Actual IP throughput achieved during the test was - 4472 kbps
But I've noticed that my router is correcting what seems to be a large number of blocks, as shown in the attached screenshot: - not sure whether this is anything to worry about, but I thought I'd post it for comment just in case it helps.

[#5]

Ah, that didn't seem to work too well, so I've attached another jpg image. Just in case you can't read the details, I've transcribed them below:-
TX blocks=474491265
RX blocks=474491196
Corrected blocks=97196367 (a bit more than 20% of RX)
Uncorrected blocks=6486

[#6]

Still monitoring, and all was ok until 08:54 this morning when the line was disconnected - now synched at 4224kbps with an IP profile of 3500kbps (dropping from 6500 and 5500 respectively). SNR margin has also dropped from 8.0Db to 5.0. Routerstats reported a sharp increase in SNR margin from 8Db to 22Db just before the disconnect, then this dropped down to 5Db. Mybroadbandspeed reports a download speed of 3616kbps. I'm not aware of anything I could have done to cause the disconnect.
Latest BT speed test results (from 11:42 this morning):-
Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 4224 kbps(DOWN-STREAM),  448 kbps(UP-STREAM)
    IP profile for your line is - 3500 kbps
    Actual IP throughput achieved during the test was - 465 kbps
The block correction count has dropped considerably since the resynch - now just about 0.07% of received blocks (was about 20%).
For a line that should apparently be able to achieve 8000kbps it still looks a bit sick. But, don't get me wrong, it's still a huge improvement over what I was getting just a few days ago.

[#7]

No disconnections since yesterday morning, but I noticed that the SNR margin had increased to 13.5Db. From reading some of the posts on the broadband speed forum, the target margin for MaxDSL should be about 6Db so, as an experiment, I decided to reboot the router to see if the synch rate improved. This did indeed have an impact, as shown by the reduced SNR margin (5.0Db) and the BT speed test that I did at 11:11 this morning:-
"Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 7008 kbps(DOWN-STREAM),  448 kbps(UP-STREAM)
    IP profile for your line is - 3500 kbps
    Actual IP throughput achieved during the test was - 3170 kbps"
If the high synch rate can be maintained, then I'm hopeful that the IP profile will also increase over the next few days. One thing that might prevent this, though, is the higher block correction count which is currently running at almost 28% - due to the lower SNR margin, I guess i.e. this may force a resynch at a lower rate, as happened yesterday morning at 08:54. A screenshot of the router stats screen is attached.

[#8]

Well, would you credit it! The line was disconnected a few seconds after I made the last post. Synch rate dropped just a little way to 6912kbps (from 7008) and SNR margin is now 5.0Db. Curiously, the line attenuation has increased very slightly to 22.5Db (from 22.0), which has never happened before i.e. it's been rock steady at 22.0 for weeks, if not months. Perhaps the rumble I heard a few minutes ago was tectonic activity moving me a few more yards south of the exchange......only kidding! And I can't think of anything in my house that could have caused this disconnection - no timer switching (the heating's off) and I haven't manually switched anything on or off either.
I can't do another BT speed test for a while, but Mybroadbandspeed shows a download speed of 3337kbps, so it seems that no drastic performance changes occurred.

[#9]

Hmmm, disconnected again - this time at 17:28 and synch rate has dropped to 1248kbps with SNR margin of just 1.0Db. BT speed test at 17:36 revealed the following:-
Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 1248 kbps(DOWN-STREAM),  416 kbps(UP-STREAM)
    IP profile for your line is - 3500 kbps
    Actual IP throughput achieved during the test was - 783 kbps
You may forgive me if I have a feeling of deja vu....
Anyone have any ideas as I really don't know what else I can do to resolve this? I wasn't even using the internet when the disconnect happened...
By the way, I am updating the PN support ticket as well.

[#10]

Hi Catweazle
I suspect it tried to up the synch rate again at which point the line became extremely unstable so it started again from the minimum synch rate which is how it is designed to work.
Not much you or PN can do about it really, there are better technologies than ADSL but it is the most cost effective.

[#11]

whats the fault threshold on this line?

[#12]

Not sure whether I can check the fault threshold rate directly, but the last time this information was provided (by PN support on 13th Jan) the rate was 921; see
INTERNAL:
  Upstream Link Info
  Loop Loss Loop Loss Add Text SNR Margin Errored Seconds HecErrors Cell Count Speed
11  6 0 0 97 448
   
  Downstream Link Info 
  Loop Loss Loop Loss Add Text SNR Margin ErroredSeconds HecErrors CellCount Speed
22  -11 0 0 97 1056
   
  DSL Max Data 
 
  BIP Interface Data 
  Current line rate Line rate change timestamp Maximum Stable Rate Recalcuated ProfileTimestamp Maximum Stable Rate
5000 2009-01-11T01:08:39 Y 2008-10-25T18:23:11 1152
   
  Fault Threshold Rate Interleaving Flag ServiceOption ServiceOption Status ServiceOption Update Timestamp
921 I 1 THIS LINE IS STABLE AND WELL WITHIN ERROR/RETRAIN LIMITS FOR THE CHOSEN SERVICE OPTION (ILQ=GREEN) 2008-03-30T1

[#13]

Hiya,
I'm afraid that the fault threshold rate is still set to 921Kbps, based on a maximum stable rate of 1152Kbps, presumably from the initial 10 day period.
Do you notice any noise on the line when the sync rate mysteriously drops?
Have you just had the single BT visit, or have there been several?

[#14]

Quote from: Bob

Try a reboot, your line profile's been at 5000kbps since Sunday morning but our systems hadn't updated to reflect this. Without reading the entire ticket history, can I ask if you've noticed any correlation with the timing of the low sync events? Does it always happen in the evening for example? On the last three occasions the line profile has dropped to 750kbps it's been between 5:00pm and 7:00pm. Is there anything that happens in your house around this time that could be generating noise on the line? Does you heating kicking then, or is that the time an electrical device like a TV or radio is commonly switched on? Given the fact that your line keeps on resynchronising at such a low level I find it difficult to believe that we're not dealing with a certain degree of noise interference. Do you have an old AM/MW radio? If so try tuning it to 612Khz and walk around the house to see if you can identify any large areas of interference. Take a look here for a little more info. Sorry to hear this has been going on for so long. It can be equally as frustrating for us trying to get to the bottom of issues like this and I'd like to see this one resolved.

[#15]

oops sorry the quote above was a little error!.. I was gonna say, try brushing your hair the other way as this may help with the speeds. LOL sorry not taking the mickey but i find that any kind of issue where no one has a clue and the usual comments come out about interferance so give the hair brushing a try!!!  my 2 penny's worth!