Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Pages: 1 ... 4 5 [6] 7 8

Author Topic: ADSL2 line problems  (Read 4348 times)

ejs

  • Kitizen
  • ****
  • Posts: 1761
Re: ADSL2 line problems
« Reply #75 on: June 25, 2018, 06:59:34 PM »

Would the banding have been a problem if I had not mentioned it?
Logged

g3uiss

  • Reg Member
  • ***
  • Posts: 264
  • You never too old to learn
    • Midas Solutions
Re: ADSL2 line problems
« Reply #76 on: June 25, 2018, 07:05:03 PM »

Yes because the speed I'm getting on this circuit is below what I always had following a line card fault, and what the ISP tells me the sync speed should be.

The ISP kept resetting the target SNR and the DLM intervened, despite the ES/SES being well below the assumed figure for DLM action.

You helpfully pointed out it was banding not target SNR.

I'm really sorry but I don't understand your post ?

Tony
Logged
Zen FTTC and Plusnet ADSL HG612 modems with Vigor 2925

konrado5

  • Reg Member
  • ***
  • Posts: 896
Re: ADSL2 line problems
« Reply #77 on: June 25, 2018, 07:43:48 PM »

But the bit loading still has all the missing tones. I thought that was of the More concern ?


Please put me right if Iíve been looking at the wrong plots ?
You've been looking at the wrong plots. It is a curiosity that earlier you had missing tones also on Hlog. Now Hlog is correct.

Quote
The extra tone with 2 bits is likly the pilot tone ?
Yes. It is.
Logged

g3uiss

  • Reg Member
  • ***
  • Posts: 264
  • You never too old to learn
    • Midas Solutions
Re: ADSL2 line problems
« Reply #78 on: June 25, 2018, 08:01:59 PM »

Thanks. So the gaps in the BPT graph are not of consequence as they are the same with both modems.

Sorry but Iím getting confused😰
Logged
Zen FTTC and Plusnet ADSL HG612 modems with Vigor 2925

konrado5

  • Reg Member
  • ***
  • Posts: 896
Re: ADSL2 line problems
« Reply #79 on: June 25, 2018, 08:07:58 PM »

Sorry. I made a typo.  You've been looking at good plots. It is a curiosity that earlier you had missing tones also on Hlog. Now Hlog is correct.
« Last Edit: June 25, 2018, 08:25:02 PM by konrado5 »
Logged

ejs

  • Kitizen
  • ****
  • Posts: 1761
Re: ADSL2 line problems
« Reply #80 on: June 25, 2018, 08:21:24 PM »

I did not intend for the fact that it's banded to be taken as some reason that there must be something for an Openreach person to go and fix. There's nothing to guarantee that a line will never get worse than whatever it was in the past.
Logged

g3uiss

  • Reg Member
  • ***
  • Posts: 264
  • You never too old to learn
    • Midas Solutions
Re: ADSL2 line problems
« Reply #81 on: June 25, 2018, 09:02:14 PM »

@EJS Thanks. So I think what your saying I should just cancel the visit, and live with the reduced rate. I am aware that things change, but I wasnít expecting a phone fault to permantly reduce my bandwidth.

I was asking for help interpreting the stats actually to avoid the need for an engineer to visit. I was hoping to identify a problem perhaps with hardware or other local issue. I did not want to say this on the forum but my wife has to have daily radio therapy for cancer treatment for 6 weeks every day needing a 40 mile round trip. I didnít want to have to send her in a taxi,so I could be here for a vist.

I wasnít wanting to say that, I just wanted to try and resolve an issue with the minimum of inconvenience. Iím now no further on. Iím greatful for all the input. 

I will just leave it to the SP to decide on the course of action
Logged
Zen FTTC and Plusnet ADSL HG612 modems with Vigor 2925

g3uiss

  • Reg Member
  • ***
  • Posts: 264
  • You never too old to learn
    • Midas Solutions
Re: ADSL2 line problems
« Reply #82 on: June 25, 2018, 09:04:00 PM »

Sorry. I made a typo.  You've been looking at good plots. It is a curiosity that earlier you had missing tones also on Hlog. Now Hlog is correct.

Thank you thatís what I saw. Unfortunately it doesnít prove a faulty modem one way or the other I donít think.

Thanks for taking the time to correct the typo. I make tons !
Logged
Zen FTTC and Plusnet ADSL HG612 modems with Vigor 2925

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31601
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: ADSL2 line problems
« Reply #83 on: June 26, 2018, 07:30:40 PM »

Would the banding have been a problem if I had not mentioned it?

I certainly would have spotted it & if I'd been around more over the past couple of days would have mentioned it.    The OP asked for help with his line being unstable for a while and dropping below the MGAL.   

The PN of late would hardly send out an engineer if they felt it wasn't warranted.   In fact they had been offering to send one out for a while but due to the OP's personal circumstances it was difficult to arrange a date and time which is why he asked if we could spot anything obvious that he could perhaps rectify himself.   
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31601
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: ADSL2 line problems
« Reply #84 on: June 26, 2018, 07:34:10 PM »

I have to say I'm a wee bit disappointed in the fact that how this has turned out.  I was going to post myself the other night about harsh comments, but in the end I bit my tongue and decided it's about time I start taking a back seat as communication for me is difficult and some days I find it hard to get across the point I am trying to make. Part of it could be the pain meds I'm on and the other part FM.  I shall be going AWOL within the next few days anyhow as I'm due an operation which will leave me a bit incapacitated for a wee while and its why I'm so busy this week as I try to do what I can before I go in hospital so I've not had much time to spend on the forum.   I have tried speech to text but found it doesn't always work well on forums for the posts I tend to make.

That leads on to what happened last night, I was aware of g3uiss's situation which is why I was trying to help and see if I could see anything, or at least any pointers that could assist if he did have to call out an engineer.

The line is performing below the MGAL, it used to be fine until he had problems with water in the DP.  Although I didn't know until very recently g3uiss is fairly local to me on a neighbouring exchange and I know there is no RF in this area.   Bear in mind also that his VDSL line does not exhibit those same blank tones either.    I still maintain I've not seen anything like that before in 15+ years of reading stats, so I feel it is right to point it out.

Whilst I agree it may be a red herring to the overall problem - something is causing those blank tones and its interesting that hlog with the Zyxel modem is fine as is QLN... so what later causes no bit load?  Am I not supposed to comment on something abnormal?

The line is quite obviously banded, you also have to consider what caused DLM to take interest in the line so quickly after a line reset.   There's several indicators that it was MBTR rather than MBTE. 
- Err Secs within MBTE limit
- Why banded but not interleaved. WBC DLM should opt for INP (Interleaving) if it was through Error rates.
- The presence of LOS and quite a lot of LOFs.


Whilst I appreciate that LOFs may not always cause a full resync it marks a period of short period time when the line is unavailable.   There's a subtle difference between resync and retrain.  Just about every technical document I checked classed LOFs as critical requiring either resync or retain.   Whilst I note what ejs said about "not a resync as we know it".   I think that bearing in mind knowing that DLM was highly likely to be taking action through MBTR figures rather than MBTE.   

OK so I sidetracked a wee bit with the mention of RDI's but TBH I still think it was a valid point to make.   What if DLM is ignoring the RDI markers (which indicate that the LOF was caused by something other than and SEF causing the LOF).  It ignores Dying Gasp messages and still counts LPRs as a retrain, so I feel I was quite justified to wonder if there was the possibility it could be doing similar with LOF's that strictly speacking should be ignored because they have an RDI marker.   I still feel justified in bringing up the topic because it may well explain why several other lines in the past have attracted DLM intervention when the resync count wasn't quite reaching the full total.  It is definitely something to ponder over so therefore I make no excuse for raising it.

I repeat no matter what technical journal you look at, they all class the following as not just error states, but critical and the causes for loss of sync
- LOF  (There should be an RDI marker if not caused by SEF - ie DLM initiated type resync at DSLAM)
- LOL
- LOS
- LPR  (This is usually EU disconect of modem - and we know for counts this and ignores the dying gasp signal)   



Anyhow back to g3uiss's problem.   I feel that he should go ahead with the OR visit.   Something is constantly causing DLM to take an interest and further cripple his speeds.   It doesnt do that for nothing and its why I said I was not too happy with the LOF count.

What is causing the LOF's is another matter.     I find it curious the Zyxel marked those tones during the sync process and whilst its not what is causing DLM to spazz out, it still leaves the possibility that there is something causing retrains.   Thus I feel it would be beneficial to mention to the engineer that DLM probably banded the line due to MBTR (retrains) rather than MBTE (Errors).

Finally whilst the Zyxel wasn't on very long, it does look like the error rate was slightly less during that period.   The SNRM is also higher which means he should get a better sync speed with it if wasnt for the fact the line wasn't banded.   I feel it may be beneficial at some point to run the Zyxel for a longer period to get a better picture.    However not now as an engineer is coming on Friday so let him see it in its current state with the HG612

I'm in no hurry to get the VMG1312 back.  I currently have a VMG8324 on my line and when I get chance I have a VMG8924 to put on and VDSL for me is off the radar for a while.   My own line has just dropped below MGAL, but atm I have other things on which mean that now is not best time for logging faults with PN if I'm not going to be here or in a position to be swapping out modems myself.
What may be beneficial that if after the Openreach visit,  the VMG1312-B10D does perform better on your line purchase of a B10A variant may well eke out more from your connection.

OK I'm done - hitting send typo's and all.   
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

konrado5

  • Reg Member
  • ***
  • Posts: 896
Re: ADSL2 line problems
« Reply #85 on: June 26, 2018, 08:19:47 PM »

Quote from: kitz
Whilst I appreciate that LOFs may not always cause a full resync it marks a period of short period time when the line is unavailable.   There's a subtle difference between resync and retrain.  Just about every technical document I checked classed LOFs as critical requiring either resync or retain.   Whilst I note what ejs said about "not a resync as we know it".   I think that bearing in mind knowing that DLM was highly likely to be taking action through MBTR figures rather than MBTE.   
But always if there is one LOS there are 7 or 9 LOFs.
Logged

g3uiss

  • Reg Member
  • ***
  • Posts: 264
  • You never too old to learn
    • Midas Solutions
Re: ADSL2 line problems
« Reply #86 on: June 26, 2018, 09:00:54 PM »

I have to say I'm a wee bit disappointed in the fact that how this has turned out.  I was going to post myself the other night about harsh comments, but in the end I bit my tongue and decided it's about time I start taking a back seat as communication for me is difficult and some days I find it hard to get across the point I am trying to make. Part of it could be the pain meds I'm on and the other part FM.  I shall be going AWOL within the next few days anyhow as I'm due an operation which will leave me a bit incapacitated for a wee while and its why I'm so busy this week as I try to do what I can before I go in hospital so I've not had much time to spend on the forum.   I have tried speech to text but found it doesn't always work well on forums for the posts I tend to make.

That leads on to what happened last night, I was aware of g3uiss's situation which is why I was trying to help and see if I could see anything, or at least any pointers that could assist if he did have to call out an engineer.

The line is performing below the MGAL, it used to be fine until he had problems with water in the DP.  Although I didn't know until very recently g3uiss is fairly local to me on a neighbouring exchange and I know there is no RF in this area.   Bear in mind also that his VDSL line does not exhibit those same blank tones either.    I still maintain I've not seen anything like that before in 15+ years of reading stats, so I feel it is right to point it out.

Whilst I agree it may be a red herring to the overall problem - something is causing those blank tones and its interesting that hlog with the Zyxel modem is fine as is QLN... so what later causes no bit load?  Am I not supposed to comment on something abnormal?

The line is quite obviously banded, you also have to consider what caused DLM to take interest in the line so quickly after a line reset.   There's several indicators that it was MBTR rather than MBTE. 
- Err Secs within MBTE limit
- Why banded but not interleaved. WBC DLM should opt for INP (Interleaving) if it was through Error rates.
- The presence of LOS and quite a lot of LOFs.


Whilst I appreciate that LOFs may not always cause a full resync it marks a period of short period time when the line is unavailable.   There's a subtle difference between resync and retrain.  Just about every technical document I checked classed LOFs as critical requiring either resync or retain.   Whilst I note what ejs said about "not a resync as we know it".   I think that bearing in mind knowing that DLM was highly likely to be taking action through MBTR figures rather than MBTE.   

OK so I sidetracked a wee bit with the mention of RDI's but TBH I still think it was a valid point to make.   What if DLM is ignoring the RDI markers (which indicate that the LOF was caused by something other than and SEF causing the LOF).  It ignores Dying Gasp messages and still counts LPRs as a retrain, so I feel I was quite justified to wonder if there was the possibility it could be doing similar with LOF's that strictly speacking should be ignored because they have an RDI marker.   I still feel justified in bringing up the topic because it may well explain why several other lines in the past have attracted DLM intervention when the resync count wasn't quite reaching the full total.  It is definitely something to ponder over so therefore I make no excuse for raising it.

I repeat no matter what technical journal you look at, they all class the following as not just error states, but critical and the causes for loss of sync
- LOF  (There should be an RDI marker if not caused by SEF - ie DLM initiated type resync at DSLAM)
- LOL
- LOS
- LPR  (This is usually EU disconect of modem - and we know for counts this and ignores the dying gasp signal)   



Anyhow back to g3uiss's problem.   I feel that he should go ahead with the OR visit.   Something is constantly causing DLM to take an interest and further cripple his speeds.   It doesnt do that for nothing and its why I said I was not too happy with the LOF count.

What is causing the LOF's is another matter.     I find it curious the Zyxel marked those tones during the sync process and whilst its not what is causing DLM to spazz out, it still leaves the possibility that there is something causing retrains.   Thus I feel it would be beneficial to mention to the engineer that DLM probably banded the line due to MBTR (retrains) rather than MBTE (Errors).

Finally whilst the Zyxel wasn't on very long, it does look like the error rate was slightly less during that period.   The SNRM is also higher which means he should get a better sync speed with it if wasnt for the fact the line wasn't banded.   I feel it may be beneficial at some point to run the Zyxel for a longer period to get a better picture.    However not now as an engineer is coming on Friday so let him see it in its current state with the HG612

I'm in no hurry to get the VMG1312 back.  I currently have a VMG8324 on my line and when I get chance I have a VMG8924 to put on and VDSL for me is off the radar for a while.   My own line has just dropped below MGAL, but atm I have other things on which mean that now is not best time for logging faults with PN if I'm not going to be here or in a position to be swapping out modems myself.
What may be beneficial that if after the Openreach visit,  the VMG1312-B10D does perform better on your line purchase of a B10A variant may well eke out more from your connection.

OK I'm done - hitting send typo's and all.   

Greatful for all that info. I will post back following the visit, (and when the line is unbranded and stable try the Zyxel, and source one you recommend).

As expected since banding the line has been stable but well below MGALS.



Logged
Zen FTTC and Plusnet ADSL HG612 modems with Vigor 2925

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31601
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: ADSL2 line problems
« Reply #87 on: June 26, 2018, 10:35:12 PM »

But always if there is one LOS there are 7 or 9 LOFs.

I saw you mention that the other day and wondered where that had come from.  Is there anything definitive about that or is it an observation.    Years ago I saw someone mention 1 = 4...  and quite often 1 =7 does crop up,  yet there are examples out there that show otherwise. 

Code: [Select]
LOS: 16 0
LOF: 25 0

LOS: 4 0
LOF: 8 0


LOS: 4 0
LOF: 7 0

LOS: 7 0
LOF: 12 0
LOM: 26 0


I'm well aware that LOFs may not always cause a full resync if the line recovers during the integration process, but something is causing DLM to take note of g3uiss's line and the pointers are its MTBR rather than err secs because of capping yet no interleave. 


There wasn't anything I could find which says there is a ratio..  just "Prolonged LOS => LOF, but not always LOF => LOS"

and
7.1.1.1.1 Loss of signal (LOS) failure
An LOS failure is declared after 2.5 Ī 0.5 s of contiguous LOS defect, or, if LOS defect is present
when the criteria for LOF failure declaration have been met (see LOF definition below). An LOS
failure is cleared after 10 Ī 0.5 s of no LOS defect.
7.1.1.1.2 Loss of frame (LOF) failure
An LOF failure is declared after 2.5 Ī 0.5 s of contiguous SEF defect, except when an LOS defect or
failure is present (see LOS definition above). An LOF failure is cleared when LOS failure is
declared, or after 10 Ī 0.5 s of no SEF defect.


One thing we may see if LOS if a LOF RDI has been declared (no SEF defect).   Example of an RDI commonly used by Openreach/BTw is DLM causing the line to retrain, which is when we may see 1=7 quite often?   

The ratio thing isn't something I had looked into before, and I acknowledge you are very good at spotting patterns.  Could the 1=7 be as a result of the DSLAM bringing the line down without SEF defects being present?  I honestly don't know, but I am now signing off.

Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

konrado5

  • Reg Member
  • ***
  • Posts: 896
Re: ADSL2 line problems
« Reply #88 on: June 26, 2018, 10:38:45 PM »

Quote
Is there anything definitive about that or is it an observation
This is my observation on Netgear DGND3700v2 when I have  resync done ISP or resync caused by SHINE.
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31601
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: ADSL2 line problems
« Reply #89 on: June 26, 2018, 10:47:40 PM »

This is my observation on Netgear DGND3700v2 when I have  resync done ISP or resync caused by SHINE.

Ahh thank you.    ISP forced resync would fit with the 1=7 for RDIs.   Not something I'd taken note of with for SHINE though.
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker
Pages: 1 ... 4 5 [6] 7 8