Odd noise spikes causing speed issues and disconnections

[duckson]

Yep weird alright.
Maybe the exchange equip. is going wonky. 

At least it shows my line can run a sync of 8128kbps with a decent noise margin (7db give or take)....for a short time in this instance anyway!

[hake]

I found that my connection recently changed from interleaved to fast path without me requesting it.  Fortunately, the connection is now fast and stable (for the first time since summer 2006 but how long will it last?) and I have asked my ISP that it be left as it is, i.e. fast path.  I could believe that changes happen at BT's whim and since I am not advised that a change has been made, I am mystified when the behaviour of the connection suddenly changes, usually for the worse.  No wonder that people are hostile towards ADSL service providers and BT in particular.

I suppose it is impractical for BT advise the ISP (for customer information) when they have changed something that will affect the performance of a connection.

[waltergmw]

It certainly looks as if Zen will have to be involved. If you e-mail your results to:-

support@zen.co.uk

quoting your fault reference number and then call them, they can see what you are complaining about.

Clutching at straws, you might just check you have good modem power and cable connections.

Kind regards,
Walter

[duckson]

(seen your post as i'm writing this Walter, i think everything is ok with me on the PSU/cable front if you read below (not withstanding i've tried 3 routers and 4 ADSL cables and filters...)).

Well confusion reigns. 

Lost PPP not long ago and it took 15-20mins for me to log into Zen. I also lost sync, got it back (at 8128kbps / ~6.5db SNRM!!), wouldnt connect to Zen for a 14 minutes (LCP Down) and then its up again now. Wonder how long 8128kbps will hold. Another thing, logged into the Zen portal and from 12:34pm today i have a 7150 profile again! I think Mr BT man has been messing about, reset me to a 6db margin and put me on Fast Path?!

On top of this i set my parents up running routerstats this afternoon with one of my spare routers, a Draytek 2800G. I phoned them when i couldnt get any net access just now and they confirmed they couldnt either....around the same time their sync dropped as well and they couldnt connect to Zen thereafter for a while. They are on the same exchange and live on the same road as me a few hundred yards away. I've got their graphs / Log to prove this....all a bit coincidental dont you think?

Also my sister in law and mother in law (also on the same exchange) said they had sync drops today (this afternoon sometime), Mother in law is on BT but i'm not sure what the Sister in law is on now (was Tiscali but she changed to something else cus her boyfriend gets free net access through work).

[duckson]

Well it lasted an hour and a 1/2 then dropped sync (large noise spike) and reconnected at 6976kbps / 10-11db noise margin. 
Up until then it was quite a smooth noise margin keeping north of 6db even.

[waltergmw]

Hi Stu,

With the information you have, including the phone numbers from your relations, Zen should be able to say there is a probable faulty DSLAM (or possibly other equipment) in the exchange.
Nearby houses could perhaps be using the same cable so might be susceptible to a common noise spike but it seems highly unlikely that four different services would be all using one cable.
Zen will almost certainly be using BT Wholesale services as will BT retail. It's only LLU providers who would be using non-BT equipment.

Good luck with Zen and BT,
Kind regards,
Walter

[duckson]

Since 8pm last night (i disconnected at 23:45 to 23:54):-




It appears i'm maybe back on the 10 day training possibly, my Zen portal page shows the MSR @ 288 and FTR @ 288 which changed last night just before midnight. Previous values were set in March 2007.

[duckson]

I have another BT engineer booked for this Friday and hopefully they are going to do a 2hr extended test from the exchange end.
Zen had to push it up to "BTw Interventions" team to get this done as they wont take my logs/graphs as evidence that something isnt "right". 

Aside from this i've held sync at 7008kbps for 2 days now, its lower than my normal 8128kbps as the noise margin needs to be 10-11db so the spikes dont drop the connection. If i resync during daytime at least i reconnect at 8128kbps and ~7db for a while (couple of hours if i'm lucky).

Does the Router log for the 48 hours look normal or do i have a large amount of errors? (ADSLNation faceplate, ADSLNation "PRO" ADSL cable, 2 x standard extension phone lines to 2 Sky boxes and house phone plugged into front of face plate).

Downstream
Noise Margin:     10.7  dB
Connection Rate:  7008  Kbps
Line Attenuation: 33.0  dB
Power:            19.8  dBm
Max Rate:         7552  Kbps
 
SF:               10145757
SF Errors:        18086
Reed Solomon:     689911506
RS Corrected:     6628454
RS Un-Corrected:  60968
HEC:              13864
Errored Seconds:  1529
Severe ES:        349

Interleave Depth: 32
Bitswaps:         0

Upstream
Noise Margin:     22.0  dB
Connection Rate:  448   Kbps
Line Attenuation: 19.5  dB
Power:            12.4  dBm
Max Rate:         1124  Kbps
 
SF:               10176267
SF Errors:        2
Reed Solomon:     86497037
RS Corrected:     28
RS Un-Corrected:  0
HEC:              2
Errored Seconds:  0
Severe ES:        0

Interleave Depth: 4
Bitswaps:         0


Total Uptimes (From SF counts):
WAN:   2 days, 00:03:58
LAN:   2 days, 02:24:37
 
CRC:  19263
LOS:  1
LOF:  9
ES :  1529

[duckson]

Replying to my own post but i'd remembered i'd switched on Telnet on my router (DG834GT) and set the all the different errors to plot on Routerstats....each jump up in errors (CRC, SF error etc) occurs exactly when there is a noise blip (eg 1000 CRC errors over the duration of the spike (30secs to a minute)). To be expected i suppose so i'd guess these amount of errors arent normal!!

I do recall from a year or 2 back having a very small amount of CRC errors! 

Another question....does the BT equipment at the exchange pick this sort of info up and would BT be able to look at it and realise something isnt as it should be?

[jeffbb]

Hi
quote its lower than my normal 8128kbps  

Interleave is back on so the synch can only be up to 7616Kbps

your stats   for 48hrs

SF:               10145757
SF Errors:        18086
Reed Solomon:     689911506
RS Corrected:     6628454
RS Un-Corrected:  60968
the above relate to your WAN uptime (connection to the exchange )

HEC:              13864         ( not sure when these get reset )


those below are the total uptime errors since reboot , may be the same time as WAN time
Errored Seconds:  1529
Severe ES:        349
to me they seem high but that is by comparison to my line

my stats for a line with 29db attenuation
Wan up time  of    1 days, 08:59:11
 
SF:               6975923
SF Errors:        1
Reed Solomon:     474362794
RS Corrected:     690
RS Un-Corrected:  1

HEC:              1

LAN uptime :   10 days, 08:37:39
Errored Seconds:  4
Severe ES:        0
Interleave Depth: 32

I still don't understand how your synch rate sometimes is so high and why with your problems your target SNR does not appear to be raised . Maybe that is part of the problem ?


Hope you get some help from BT (hope it gets very unstable during the 2hr test  )

Regards Jeff
edit : crossed your post
 quote Routerstats....each jump up in errors (CRC, SF error etc) occurs exactly when there is a noise blip (eg 1000 CRC errors over the duration of the spike (30secs to a minute)).

the errors and drop in SNR margin and or disconnection will be related . the problem is which came first ?

[duckson]

Jeff, i've always had interleave on and synced at 8128kbps....its possible and its not the router cus i've done it on 3 different routers. 

Found an old post of mine from Nov 2007 from another forum and over 24hrs my 3COM router had reported:-

Defect Indication
Indicator Name Near End Indicator Far End Indicator
Fast Path FEC Correction 0 0
Interleaved Path FEC Correction 3060 6889268
Fast Path CRC Error 0 0
Interleaved Path CRC Error 0 32
Loss of Signal Defect 0 ---
Fast Path HEC Error 0 0
Interleaved Path HEC Error 0 0
Statistics
Received Cells 1217034
Transmitted Cells 230917

Obviously no problems there!
Before the BT engineer put my line on re-training i had had my SNR Margin increased to 9db by the DSLAM....now back on 6db still, i dont want it raised as that would just be trying to brush the underlying problem under the carpet.

[duckson]

Ran BT speedtest as i felt the net wasnt running to fast and got:-

Download speedachieved during the test was - 40283204 Kbps
 For your connection, the acceptable range of speeds is 600-7150 Kbps.
 Additional Information:
 Your DSL Connection Rate :7008 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
 IP Profile for your line is - 5500 Kbps

The green bar on the 0 - 7150 scale was really low though.
Speedtest.net and ThinkBroadband speed tester are all reporting 1.5-2mbit.....whenever i've tested in the past it been very near to my IP Profile (5000-7150).

[waltergmw]

I have noted today that BT's speedtester is not working properly.

See:-

http://forum.kitz.co.uk/index.php/topic,6546.msg141008.html#new

I have tried two other lines today on the same exchange. On one the speedtester just hangs after entering the number and doesn't ask the question on the phone number pop-up.
The second was a brand new service I was commissioning and gave a stupid answer well above the sync speed again.

Kind reagrds,
Walter

[duckson]

Line training now finished, just need the problem fixing now! 

MSR FTR MSR Reset Status Date
6240 4992 N 12-Jan-2010 02:05
288 288 N 02-Jan-2010 12:06
6816 4771 N 07-Mar-2007 02:02
2272 2272 N 26-Feb-2007 00:00

No idea why FTR is higher than my last setting when MSR is lower? 

[philip_l]

Hi

What you describe throughout is impulse noise, there is nothing wrong with your phone line or setup especially if others experience the same thing.

It can very difficult to track down, logging dates and times will help towards possibly finding the cause, but you will need specialists at BT/Openreach to take an interest in fixing the problem, they will if they get enough complaints and someone makes the connection that the same impulse noise source is the cause.

Where this noise comes from?  Could be anywhere?  Anyone using electrical equipment could be the cause, and they are probably completely unaware it is having an effect.

Let us know how you get on.

Regards

Phil