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Upstream Speed Dropping

FIXED
Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Upstream Speed Dropping

Could some of the Forum experts help me understand what is happening with my broadband please?

On Friday, I contacted Plusnet via chat to ask if they could reset my profile to match the BT speed. The CSC ran a test on the line, and reset it - all well and good, so far.

However, since then, the connection has been dropping two or three times every evening and when it comes back up, the downstream speed is virtually unchanged but the upstream speed drops each time.

Router is connected to the master socket which has a filtered faceplate, I've not yet tested connected to the test socket but I have tested with a different router.

Current line stats, from a Billion 7700n:

Statistics -- xDSL

 
Mode: ADSL_G.dmt
Traffic Type: ATM
Status: Up
Link Power State: L0
 
  Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (0.1 dB): 59 100
Attenuation (0.1 dB): 500 315
Output Power (0.1 dBm): 198 123
Attainable Rate (Kbps): 5792 740

 

  Path 0   Path 1  
  Downstream Upstream Downstream Upstream
Rate (Kbps): 5248 576 0 0
 
K (number of bytes in DMT frame): 165 19 0 0
R (number of check bytes in RS code word): 14 16 0 0
S (RS code word size in DMT frame): 1.00 8.00 0.0 0.0
D (interleaver depth): 32 4 0 0
Delay (msec): 8.00 8.00 0.0 0.0
INP (DMT symbol): 1.25 0.11 0.0 0.0
 
Super Frames: 1318176 1318176 0 0
Super Frame Errors: 933 776 0 0
RS Words: 26298559 3286729 0 0
RS Correctable Errors: 123749 6 0 0
RS Uncorrectable Errors: 1592 0 0 0
 
HEC Errors: 2828 349 0 0
OCD Errors: 7 0 0 0
LCD Errors: 7 0 0 0
Total Cells: 81374237 0 0 0
Data Cells: 3390091 0 0 0
Bit Errors: 0 0 0 0
Total ES: 343 0
Total SES: 11 0
Total UAS: 83

83

Picture attached is from Routerstats Lite, showing this evening's drop. Unfortunately it doesn't show the change in upstream but this went from 863 to the 576 shown above. Router reconnected at 20.21 so the uptime for these stats is approx. 2 hrs

A router re-boot seems to return the upstream to normal. Ideas?

28 REPLIES
hitchhiker43
Aspiring Pro
Posts: 171
Thanks: 20
Fixes: 4
Registered: 06-07-2016

Re: Upstream Speed Dropping

This is possibly REIN in the upstream frequencies (below 138Khz). I have been experiencing REIN in my downlink for months so I know the symptoms very well!

What happens is the interference starts strong and knocks out the link and then weakens slowly such that at sync the attainable speed at 6db is rather low however a later reboot after the interference has completely gone resyncs at a higher rate even though its still 6db snr. In your case from the above stats it seems there was 4db of interference at sync (6+4 = 10).

This is very difficult to prove and resolve, I strongly suggest you use DSLSTATS to plot your snr and catch some events to send to pnet, also try and find it on the radio in this case probably long wave during the event.  Good luck Smiley

Tp-link W8960n on longgggggggg line!
Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

Yes, I've started dslstats running now that I've changed my router back to the Billion 7700n from the plusnet 2704n. No sign of REIN as yet on the upstream - plenty on the downstream but, like you, I've been living with this for a long time being on an overhead supply in the country :-)

Plusnet Help Team
Plusnet Help Team
Posts: 13,489
Thanks: 248
Fixes: 68
Registered: 27-04-2007

Re: Upstream Speed Dropping

Full diagnostic tests don't sow any issues Carfail but cheers for reporting a fault, we'll look into that for you.

If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

Well, there's definitely something going on. Line dropped again yesterday evening, resynced with lower speeds on both down and up, up affected more than down! Graphs attached. Looking back through my records, it looks as if something happened around the bank holiday - when we were away. Up to 30 August, router and line had been connected without major issues for over 70 days. Came back on 31 August and the stats were as follow:

6 - Uptime:

1 days 03:44:23

Uptime:

80D 12H 2M 23S

Line Rate - Upstream (Kbps):

736

Line Rate - Downstream (Kbps):

4928

ShowtimeStart (seconds)

125677

Date/Time:

Wed Aug 31 09:20:20 2016

Statistics -- xDSL
 

 

Mode:

ADSL_G.dmt

 

 

Traffic Type:

ATM

 

 

Status:

Up

 

 

Link Power State:

L0

 

 

 

 

Downstream

Upstream

 

 

Line Coding(Trellis):

On

On

 

 

SNR Margin (1 dB):

9.4

10.0

 

 

Attenuation (1 dB):

48.5

31.5

 

 

Output Power (1 dBm):

19.5

12.3

 

 

Attainable Rate (Kbps):

5932

904

 

 

 

 

Path 0

 

Path 1

 

 

Downstream

Upstream

Downstream

Upstream

Rate (Kbps):

4928

736

0

0

 

K (number of bytes in DMT frame):

155

24

0

0

R (number of check bytes in RS code word):

14

16

0

0

S (RS code word size in DMT frame):

1.00

8.00

0.0

0.0

D (interleaver depth):

32

4

0

0

Delay (msec):

8.00

8.00

0.0

0.0

INP (DMT symbol):

1.33

0.10

0.0

0.0

 

Super Frames:

50653431

50653431

0

0

Super Frame Errors:

110745

76462

0

0

RS Words:

502278226

62851635

0

0

RS Correctable Errors:

79274

1235

0

0

RS Uncorrectable Errors:

15490

0

0

0

 

HEC Errors:

354321

72501

0

0

OCD Errors:

53

0

0

0

LCD Errors:

53

0

0

0

Total Cells:

1459417141

0

0

0

Data Cells:

39535706

0

0

0

Bit Errors:

0

0

0

0

 

Total ES:

6231

0

 

 

Total SES:

1726

0

 

 

Total UAS:

2308

797

 

 

 

Note the upstream SNR and attenuation - prior to this it has always been a consistent 11 and attn of 31, with a max speed of 1044 - absolutely no fluctuation. Curiouser and curiouser!

Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

I've just updated ticket 13305611 in response to an email sent saying that interleaving will be 'turned on' on the line. As interleaving is already on the line, to a depth of 32 downstream and 4 upstream, I don't really think this is an answer Sad

Line has just dropped 4 times in the space of 5 minutes during a heavy rain shower - I think that this, coupled with the huge increase in errors on the line in the last few months, suggests that there is a bit more wrong than 'turning on interleaving' will fix - unless, of course, the drops were caused by OR/Plusnet?

I hope that one of the Plusnet regulars on here will see this and can help Smiley

hitchhiker43
Aspiring Pro
Posts: 171
Thanks: 20
Fixes: 4
Registered: 06-07-2016

Re: Upstream Speed Dropping

Not being the man on the spot so to speak it's a bit hard to interpret, but looking at your plots I would say at least two of them the DLM has decided to resync, as I discovered it can do this any time of day if it thinks the error rate is becoming excessive. On another occasion there is obviously a severe noise event in the downlink. It would be helpful to plot both the uplink and downlink snr simultaneously so we can see whats going on, for example the downlink seems fine when the DLM resyncs but that could have been caused by a problem in the uplink, also recording the crc errors in both directions can be illuminating. Going by your losses your line is quite long like mine and probably susceptible to REIN, do you have overhead power and telephone, are the wires clipped together, it could be the same problem as I had and the REIN in the power cables has started while you were away. Try and get Pnet to lockdown the DLM to avoid it confusing the situation Smiley try the AM radio diagnostic tool, it worked for me Smiley best of luck Smiley

Tp-link W8960n on longgggggggg line!
Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

Thanks for your comments. Yes I am on a long line and there is some REIN but these issues have just started. I've just set up a new router (Billion 8800NL R2) which I am now monitoring with dslstats. I am monitoring upstream and down, but funnily enough, there is no fluctuation in the SNR upstream. Will continue monitoring and update when more information is available. Just had another shower of rain here and another drop Sad

Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

How's this for an SNRM graph?!!!!

hitchhiker43
Aspiring Pro
Posts: 171
Thanks: 20
Fixes: 4
Registered: 06-07-2016

Re: Upstream Speed Dropping

Thats terrible BUT why is the uplink plot completely flat with no noise ripple on it at all, thats unusual! Can you try taking bit loading plots during the interference ? to see if its broadband or particular frequencies ?

Tp-link W8960n on longgggggggg line!
Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

I've managed to capture some and I'll upload tomorrow. It's mainly in the higher frequencies though.

Caerefail
Rising Star
Posts: 91
Thanks: 8
Fixes: 2
Registered: 07-09-2015

Re: Upstream Speed Dropping

Finally got back to this!

I've uploaded two graphs showing the bitswaps and SNR per Tone last night when the SNRM was all over the place. Funnily enough, weather is dryer today and the line is behaving - more or less - but there were 24 disconnections last night! Upstream speed is abysmal though - screen shot also attached. Help please anyone!!!!

alanalpha
Dabbler
Posts: 19
Registered: 24-07-2016

Re: Upstream Speed Dropping

Line has just dropped 4 times in the space of 5 minutes during a heavy rain shower - I think that this,

get the faceplate on the exchange or cabinet checked for rust or corrosion (if so must be replaced u loose internet for an hour) rain or making a phone call is classic for this issue

Moderator's note by Mike (Mav): Quote fixed.

Community Veteran
Posts: 5,172
Thanks: 480
Fixes: 20
Registered: 10-06-2010

Re: Upstream Speed Dropping

I'd recommend getting switched to ADSL2 rather than ADSL1 with uncapped upstream. This is independent from anything else which may need fixing. It may not be any faster, but could be more stable.

Check for any noise on the phone line, especially while the ADSL is dropping out - in which case it would need to be addressed as a phone fault.

hitchhiker43
Aspiring Pro
Posts: 171
Thanks: 20
Fixes: 4
Registered: 06-07-2016

Re: Upstream Speed Dropping

Just looking at your latest plots your uplink is crazy, maybe your modem is faulty!

I find it hard to believe the snr plot is totally flat with no noise but then the snr per tone plot is even crazier, 0dB across the entire uplink, finally the uplink rate is only 192Kbps, senseless! Have you checked your modem configuration ? have you checked with pnet they are not capping your uplink for some reason ? have you checked the BTperformance tester uplink IPprofile ? It would also be useful to check the modem QLN and Hlog plots for normality or otherwise (post if you like), on dslstats try combining the bitloading and snr plots then the headroom is clear Smiley

Tp-link W8960n on longgggggggg line!