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Message 21 of 56

Re: SNR fluctuation and banded after line upgrade

Hi @a_e I can see that we have received your details into our queue. We are quite busy at the moment but we will be in touch once you reach the top of the queue and we should be able to get this sorted for you then.

 

cheers

John

 

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a_e
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Message 22 of 56

Re: SNR fluctuation and banded after line upgrade

I just thought I’d keep this thread updated for reference until a mod comes through to remove the banding.

 

The attainable rate has since been increased to 6400/1300! The SNR ranges from around 8-9dB during the day and 3-4dB at night. 

 

Current rate is still banded at 2270/828. 

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Distinguished Sage
Distinguished Sage
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Message 23 of 56

Re: SNR fluctuation and banded after line upgrade

you are still in banded profile but you not see such a swing in noise margin from 8/9 to 3/4db suggesting there is a line problem and even if mods get you out of banding I just wonder how long it will last before you are back in a banded profiile



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a_e
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Message 24 of 56

Re: SNR fluctuation and banded after line upgrade

Just to update this thread- I seem to still be having problems! I’d like to get in contact with the mods again if possible please @JohnC2 @RobbieMac to request a SNR reset, banding to be removed and for interleaving to be kept on.

 

Robbie was previously assigned to my case (9/02/18) where he removed the ‘stuck’ banding. Thanks for this Robbie!

 

After Robbie intervened, my SNR was still fluctuating too extremely on ADSL2 modulation and kept spiking. There was also the same odd inference issue clearly visible on previous SNR graphs.

 

The SNR spikes have caused a banded profile again!

 

I have since switched back to G.dmt modulation on my router where the SNR is much more stable, but is at 17dB down / 7dB up. The interference issue on the SNR has also disappeared! 

 

Please could I have the SNR reset and for the banding to be removed so I can monitor the performance further? I think last time interleaving was switched off, could I please request to keep interleaving on as I think fast path was causing further problems?

 

I’d be very grateful if a mod could help.

 

Thanks for all help so far

 

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Distinguished Sage
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Message 25 of 56

Re: SNR fluctuation and banded after line upgrade

can you post stats from your router

 

as I said previously if your conenction is not stable resetting noise  margin and getting out of banding is pointless as you will just be back where you started in no time  you need to find cause of the conenction problems before you are going to make any progress



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a_e
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Message 26 of 56

Re: SNR fluctuation and banded after line upgrade

The only thing that has changed is the broadband being regraded to ADSL2+ and me changing the router modulation to ADSL2 (which caused SNR problems).

 

I wanted to eliminate any hardware problems first by going back to the original modulation setting (G.dmt) which has been in effect for 6 days with a much more stable SNR. The Upstream is a little odd at a fixed 7dB though!

 

Other options are a faulty microfilter or faulty router. If I’m right, a faulty microfilter usually shows symptoms of a dialup noise through the phone (which isn’t happening). I don’t think the router is faulty, or well I hope not! It’s only 10 months old! 

 

Quiet line test is still crystal clear and I’ve never heard any noise from frequent tests at various times of day for a few weeks now.

 

Other things I can think of - there are currently BT/Openreach works going on in my village installing new cabinets and fibre cabling. Maybe something has been disturbed?

 

Router stats below:

 

Line Rate - Upstream (Kbps)768
Line Rate - Downstream (Kbps)2272
Default Gateway / IPv4 Addresspppoa0 (DSL) / 31.49.81.188
Connection Time6 Day(s) 19:16:36

 

xDSL
ModeADSL_G.dmt
Traffic TypeATM
StatusUp
Link Power StateL0
 
 DownstreamUpstream
Line Coding (Trellis)OnOn
SNR Margin (dB)15.67.0
Attenuation (dB)36.523.5
Output Power (dBm)18.512.5
Attainable Rate (Kbps)5404960
 
Rate (Kbps)2272768
 
K (number of bytes in DMT frame)7225
R (number of check bytes in RS code word)28
S (RS code word size in DMT frame)2.002.00
D (interleaver depth)84
Delay (msec)4.004.00
INP (DMT symbol)0.050.12
 
Super Frames4404378141894549
Super Frame Errors92051452
RS Words1175666407587831066
RS Correctable Errors2740637
RS Uncorrectable Errors102580
 
HEC Errors180366433
OCD Errors340
LCD Errors340
Total Cells31498880370
Data Cells9700015690
Bit Errors00
 
Total ES4415255
Total SES517
Total UAS380338
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Distinguished Sage
Distinguished Sage
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Message 27 of 56

Re: SNR fluctuation and banded after line upgrade

your still in a banded profile hence the high noise marging - you don't get banded profile on adslmax  your up speed still looks like adsl2

 

have you tried replacing the filter when connected to test socket?



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a_e
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Message 28 of 56

Re: SNR fluctuation and banded after line upgrade

Yep, I went back into a banded profile a few days after Mod help. I think the SNR swings did it and possibly my line couldn’t cope with the interleaving being switched off causing a massive load of errors.

 

I’m on a recently upgraded ADSL2+ service, however, I’ve changed the router modulation to G.dmt for stability because the ADSL2 and ADSL2+ modes were too unstable and the SNR would fluctuate too much and drop too low. I now don’t get this on G.dmt which is why I want to see if reseting the SNR and banded profile helps.

 

I haven’t tried replacing the filter just yet because I wanted to keep the line stable to monitor any change. However, I am still connected to the test socket.

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Distinguished Sage
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Message 29 of 56

Re: SNR fluctuation and banded after line upgrade

Your stats are still very similar to before when you were in banded profile and only changed when mods released the banding

 

i think you need engineer visit to find out the cause of the large noise margin fluctuations as that is not normal. Until the cause if found and fixed you are not going to get a good speed/connection 



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a_e
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Message 30 of 56

Re: SNR fluctuation and banded after line upgrade

To illustrate what I mean. 

 

SNR before mods released banding and ADSL2 modulation ON (manually configured):

 

ADSL2_ON_2018-02-07-19.21.03-SNRMargin.png

 

SNR 3 days after mods released banding and ASL2 modulation ON (manually configured) with interleaving OFF (BT):

 

ADSL2_after_banding_release_2018-02-12-23.13.39-SNRMargin.png

 

SNR with G.dmt modulation ON (manually configured) and current auto 8/4 interleaving:

 

G.dmt_ON_2018-02-21-22.44.49-SNRMargin.png

 

The SNR is much more stable with the G.dmt modulation. Each modulation has given completely different noise margins: ADSL2: 9-1dB (and quite often lower!)  G.dmt: 17-11db (lowest figure fluctuates from 13-11db from day to day). There is some kind of interference on ADSL2 modulation and the fluctuations are too unpredictable/extreme for my liking, hence why I have manually overridden any auto settings and forced G.dmt.

 

Can I rule out a micro filter issue based on the above graphs? I have experienced no drops since forcing the modulation back to the G.dmt and the router remains connected to the test socket using the same micro filter.

 

I’m happy for an engineer to visit but I got charged for a visit last year where the fault wasn’t proven to be with my home wiring!

 

Is a mod able to test for any faults on my line please?

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