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[DeluxeParrot]

Over a week ago both my phone and broadband went down and I tracked the problem back to the extension wiring punched into the NTE5A face plate coming loose. I have fixed this but my broadband speed was syncing really low. Since last sunday I've been running exclusively from the test socket of the NTE5A so my internal wiring is ruled out.

I usually sync around 37 down, 6 up. Initially it was syncing at 5 down with a massive SNR margin. After 2 days of uptime it resynced at 20, with an snr margin of 15db.

My ISP has sent a replacement router/filter etc and I've been using that since Thursday and a DLM reset was performed on Friday after they apparently saw that it had capped me.

I know the cabinet I'm on (ECI) was full last year and they have put in an extra one about 6 months ago.

Here's the stats I've been collecting:

Technicolor TG589vn V3 (my usual isp provided modem):

Code: [Select]

xdsl info expand=enabled
Physical Layer Statistics:       

  Modem state:                  up
  Up time (Days hh:mm:ss):      1 day, 5:14:19
  xDSL Standard:                ITU-T G.993.2 Annex B (VDSL2)
  Channel Mode:                        Interleaved

  Number of reset:              1

  Chipset Vendor info (G.994.1):    Local Remote
    Country code:                  B500  B500
    ID:                            BDCM  IFTN
    Specific:                      0000  B206

  System Vendor info (showtime): Local Remote
    Country code:                0F00  0000
    ID:                          TMMB  ----
    Specific:                    3C61  0000

  Bearers generic info          DS          US       
    Payload rate [kbps]: 22399    7260   
    Attenuation [dB]:      14.8           2.2           
    Margins [dB]:          14.6           6.3           
    Output power [dBm]:    5.4            5.4           

    Number of bearers:          1
    Bearer 0                    DS          US       
      INP [DMT symbols]:    3.00           0.00           
      Delay [ms]:            8.00           0.00           
      Depth []:            393            0.00
      R:                  16        0       

G.997.1 Statistics (Current):       

  Failures:
    Line failures              Near end
      Loss of signal (LOS):    1       
      Loss of frame (LOF):    10     
      Loss of power (LPR):    0       

  Performance monitoring:
    Line PM:            Near end
      Error second (ES):      11     

    Channel PM:        Near end Far end
      Bearer 0:
        Code Violation (CV):    0        0       
        FEC:                    34380    0       

    ATM data path PM:            Near end Far end
      Bearer 0:
        HEC violation count (HEC):        0        N/A

G.997.1 Statistics (last 15 minutes):       

  Failures:
    Line failures              Near end
      Loss of signal (LOS):    0       
      Loss of frame (LOF):    0       
      Loss of power (LPR):    0       

  Performance monitoring:
    Line PM:            Near end
      Error second (ES):      0       

    Channel PM:        Near end Far end
      Bearer 0:
        Code Violation (CV):    0        0       
        FEC:                    34380    0       

    ATM data path PM:            Near end Far end
      Bearer 0:
        HEC violation count (HEC):        0        N/A

G.997.1 Statistics (last 24 hours):       

  Failures:
    Line failures              Near end
      Loss of signal (LOS):    0       
      Loss of frame (LOF):    0       
      Loss of power (LPR):    0       

  Performance monitoring:
    Line PM:            Near end
      Error second (ES):      0       

    Channel PM:        Near end Far end
      Bearer 0:
        Code Violation (CV):    0        0       
        FEC:                    34380    0       

    ATM data path PM:            Near end Far end
      Bearer 0:
        HEC violation count (HEC):        0        N/A

Since using ISP test router (FRITZ!BOX 3490):

Code: [Select]

Receive Direction Send Direction
Max. DSLAM throughput kbit/s 25000 10000
Min. DSLAM throughput kbit/s 128 128
Attainable throughput kbit/s 30400 8270
Current throughput kbit/s 25000 8084
Seamless rate adaptation off off
 
Latency 8 ms fast
Impulse Noise Protection (INP) 3 0
G.INP off off
 
Signal-to-noise ratio dB 9 6
Bitswap on on
Line attenuation dB 20 30
 
Profile 17a
G.Vector off off
 
Carrier record A43 A43

No errored seconds or CRC errors.

The line attenuation is a lot higher on the Fritz!Box from (14.8 to 20db). It's from exactly the same point, not sure which is more accurate.

BT wholesale checker shows higher expected figures:

Telephone Number XXXX on Exchange SUTTON IN ASHFIELD is served by Cabinet 58
Featured Products	Downstream Line Rate(Mbps)		Upstream Line Rate(Mbps)		Downstream Handback Threshold(Mbps)
	High	Low	High	Low
VDSL Range A (Clean)	62.5	43.8	15.3	10	39.7
VDSL Range B (Impacted)	49.1	30	13.3	6.9	22.4

Premise environment	Status
Bridge Tap	N
VRI	N
NTEFaceplate	N
Last Test Date	04-07-2018

My ISP order estimates my line speed is capable of 46500kbps. Sync history from ISP:

Code: [Select]

Upstream Downstream Sync Rate BRAS Profile Interleave Sync Date Date
7136 19300 19940 TR101 Auto 09-Jul-2018 08:08 09-Jul-2018 08:08
6208 5013 5180 TR101 Auto 08-Jul-2018 16:55 08-Jul-2018 16:55
4472 5013 5180 TR101 Auto 07-Jul-2018 05:54 07-Jul-2018 05:54
2404 4627 4781 TR101 Auto 06-Jul-2018 17:18 06-Jul-2018 17:18
4736 29588 30568 TR101 Auto 06-Jul-2018 01:52 06-Jul-2018 01:52
2376 5099 5268 TR101 Auto 06-Jul-2018 01:50 06-Jul-2018 01:50
4864 29938 30930 TR101 Auto 27-Jun-2018 06:36 27-Jun-2018 06:36
4556 30186 31186 TR101 Auto 26-Jun-2018 19:46 26-Jun-2018 19:46
5464 34706 35856 TR101 Auto 06-May-2018 00:03 06-May-2018 00:03
5416 34757 35908 TR101 Auto 05-May-2018 22:36 05-May-2018 22:36
5540 34733 35884 TR101 Auto 05-May-2018 17:07 05-May-2018 17:07
5604 35133 36296 TR101 Auto 05-May-2018 11:50 05-May-2018 11:50
5256 38714 39996 TR101 Auto 30-Apr-2018 01:33 30-Apr-2018 01:33

My concern is that it's syncing just over what my ISP will deem a problem which is 50% of expected sync speed (23250kbps in my case) and they are going to try say this is normal.

Am I expecting too much from my line? Any help appreciated.

Thanks.

[burakkucat]

Welcome to the Kitz forum. 

Looking at the data that your ISP/CP has provided it is clear that something has happened to degrade the circuit's performance. Even they should acknowledge that fact.

After viewing all the other data, I am not sure what to suggest. Perhaps you could ask your ISP/CP to consider the data that they have supplied and what they would suggest?

[Ixel]

Have you tried connecting a cheap analogue phone, or alternatively your standard phones (presumably DECT/wireless), to the test socket with nothing else plugged in and doing 17070 then 2 (quiet line test)? This is useful for seeing if there's unusual noise on the phone, as unusual noise could impact your broadband service.

Have your ISP, which I'm guessing is Zen by the looks of that 'sync history' layout from your ISP, ran a line test at all? I assume they have.

With INP 3 delay 8ms on the downstream I would expect very few to no errored seconds normally, so having no errored seconds doesn't come as a surprise.

[DeluxeParrot]

Yes I've done a quiet line test with a corded phone and it is silent. There was a faint buzz but I tested the phone in another known good line and it was the same, so it's just the electrical hum of the speaker being powered.

Yes the ISP is Zen.

I believe they have run a line test every time I've phoned them, it wasn't until the 3rd call that they said the DLM data they were looking at previously was 2 weeks old and so wasn't showing the capping.

They are going to call back tomorrow and I think mentioning the sync history will be the best approach as burakkucat suggested.

Thanks for the replies, this forum has a been a wealth of information. You all do a good service.

[RealAleMadrid]

The DLM reset has not worked, or was not done. The stats from the Fritzbox show you are on a banded profile of 25Mbps (Max DSLAM throughput) and you are syncing at that speed. I would get back to Zen and tell them to try another DLM reset. You should then get your usual sync speed.

[j0hn]

Code: [Select]

  Bearers generic info          DS          US       
    Payload rate [kbps]: 22399    7260
Banded at 22.4Mb on the Technicolor TG589vn V3

Which proves my point in another thread that banding can change on the fly between modems.

The user in question was banded at 14,999Kbps on a Broadcom modem and bought a Draytek but returned saying it performed shocking poor at only 11,399Kbps (I think?).
I argued that was a banded figure and DLM banding can change on the fly like that, especially between modems but they seemed pretty sure the Draytek was that bad.

edit: quick search found thread 1 and later thread 2

[DeluxeParrot]

Yep my line was banded, the DLM reset finally went through and my speeds rose. Including the Max DSLAM going to the 40/10 that I pay for. I am getting some errors now but these seem to be within expected tolerances now the interleaving has gone.

Code: [Select]

Receive Direction Send Direction
Max. DSLAM throughput kbit/s 40000 10000
Min. DSLAM throughput kbit/s 128 128
Attainable throughput kbit/s 34680 8665
Current throughput kbit/s 34120 8181
Seamless rate adaptation off off
 
Latency fast fast
Impulse Noise Protection (INP) 0 0
G.INP off off
 
Signal-to-noise ratio dB 7 6
Bitswap on on
Line attenuation dB 21 30
 
Profile 17a
G.Vector off off
 
Carrier record A43 A43

Seconds With Not Remediable Errors (CRC)
Errors (ES) Many Errors (SES) per Minute Last 15 Minutes
FRITZ!Box 117 0 0.02 0
Central exchange 3 0 0 0

I'm now pretty much back where I was before this all started, although I'm still in the test socket.

Is this the best my line is capable of? Maybe a little more if the SNR comes down to 6 eventually? I'm now just above the low end of an "impacted" line according to the BT wholesale checker.

How long do I need to wait before I can return to my Technicolor router without upsetting the DLM? I might check the hardware board actually and find a new one that works well with ECI cabinets.

It's my understanding that moving to an 80/20 package would be pointless if this is the best my line can do. Vodaphone are saying I'll be in the 43-62Mbps range with money off if less than 55Mbps. Interestingly they also say "Openreach Minimum speed: 39.71Mbps" which means "The Openreach Minimum Speed - if you are getting lower than this you may have the right to terminate your contract" I'm guessing the may in there makes the statement meaningless. Would I be correct in thinking the move would have no effect on my line speeds and i'd just be setting myself up for a customer service nightmare? Vodaphone are LLU in my exchange but I gather that doesn't matter for VDSL.

Thanks for your help chaps.

[j0hn]

The "may" in there just means you need to give them the opportunity to try fix the line and get it up to those speeds.

Ideally with such a low sync and high estimates you want to try get something physical done to improve the speeds before your estimates creep down.
Signing up to such an offer would no doubt see the ISP send out Openness to try improve the sync speed.

Don't you have the same kind of minimum guarantee with the current ISP though?

My attenuation is quite a bit higher than yours and I get 45MB currently (55Mb pre crosstalk). Your attenuation and estimates do suggest the line should perform better.

You can switch to the technicolor any time you like. Just try not to perform too many resyncs in a short space of time. If you are really paranoid about DLM then leave 30 mins between powering off the current modem and syncing the technicians and the DLM won't count it at all.

[DeluxeParrot]

I moved back to the technicolor modem and it synced at 39.999 so I was quite chuffed. It started off well but then I started getting short outages. It didn't resync but the CRC error rate went through the roof:



I disconnected it at this point and went back the fritz box as I didn't want DLM to kick in again (paranoid? )

Going back through the graphs I noticed other, longer bursts of CRC error's had happened earlier in the day

Errored seconds:



Also the FEC error's seem really high..

Code: [Select]

xdsl info expand=enabled
Physical Layer Statistics:       

  Modem state:                  up
  Up time (Days hh:mm:ss):      1 day, 3:35:13
  xDSL Standard:                ITU-T G.993.2 Annex B (VDSL2)
  Channel Mode:                        Interleaved

  Number of reset:              0

  Chipset Vendor info (G.994.1):    Local Remote
    Country code:                  B500  B500
    ID:                            BDCM  IFTN
    Specific:                      0000  B206

  System Vendor info (showtime): Local Remote
    Country code:                0F00  0000
    ID:                          TMMB  ----
    Specific:                    3C61  0000

  Bearers generic info          DS          US       
    Payload rate [kbps]: 39998    7462   
    Attenuation [dB]:      14.8           2.2           
    Margins [dB]:          7.1            6.1           
    Output power [dBm]:    5.7            5.7           

    Number of bearers:          1
    Bearer 0                    DS          US       
      INP [DMT symbols]:    0.00           0.00           
      Delay [ms]:            0.00           0.00           
      Depth []:            1              0.00
      R:                  16        0       

G.997.1 Statistics (Current):       

  Failures:
    Line failures              Near end
      Loss of signal (LOS):    0       
      Loss of frame (LOF):    0       
      Loss of power (LPR):    0       

  Performance monitoring:
    Line PM:            Near end
      Error second (ES):      11186   

    Channel PM:        Near end Far end
      Bearer 0:
        Code Violation (CV):    3564748  15     
        FEC:                    164235004 26     

    ATM data path PM:            Near end Far end
      Bearer 0:
        HEC violation count (HEC):        8943678  N/A

G.997.1 Statistics (last 15 minutes):       

  Failures:
    Line failures              Near end
      Loss of signal (LOS):    0       
      Loss of frame (LOF):    0       
      Loss of power (LPR):    0       

  Performance monitoring:
    Line PM:            Near end
      Error second (ES):      615     

    Channel PM:        Near end Far end
      Bearer 0:
        Code Violation (CV):    3564748  15     
        FEC:                    164235004 26     

    ATM data path PM:            Near end Far end
      Bearer 0:
        HEC violation count (HEC):        8943678  N/A

G.997.1 Statistics (last 24 hours):       

  Failures:
    Line failures              Near end
      Loss of signal (LOS):    0       
      Loss of frame (LOF):    0       
      Loss of power (LPR):    0       

  Performance monitoring:
    Line PM:            Near end
      Error second (ES):      1525   

    Channel PM:        Near end Far end
      Bearer 0:
        Code Violation (CV):    3564748  15     
        FEC:                    164235004 26     

    ATM data path PM:            Near end Far end
      Bearer 0:
        HEC violation count (HEC):        8943678  N/A

{Administrator}=>

Interestingly, looking at the graphs now, I turned it on at 4pm on the 22nd and I had virtually no FEC or CRC errors until ~6am on the 23rd. I'd assumed that's when I'd started recording but this graph below is correct... there were minimal errors until 05:35am:



I'm starting to think this might be a faulty modem?

While the errors occured I did a quiet line test and couldn't hear anything. There were no electrical interference sources I could think of and I walked to the cabinet and nobody was working on it.

Judging by the high amount of FEC errors, I'm guessing this is just the error rate reaching a point it can no longer "error correct" and they become real CRC faults. Instead of a significant event causing CRC errors and then solving itself.

The fritz!box has a lot less errors, but also syncs lower (34mb instead of 40).

[DeluxeParrot]

After doing some more reading I think I'm right that number of errors was too great for forward error correction to handle and they became actual CRC errors that killed the throughput.

I was looking at the snr to carrier graph and there's a big dip down to 2mhz and some googling suggests powerline adapters can cause interference at that frequency. I do have a set of those so I turned them off for a few hours and there's no noticable change in the graphs.

[burakkucat]

I was looking at the snr to carrier graph and there's a big dip down to 2mhz . . .

That is the effect of the DSPBO, required so as not to "swamp" exchange based services, and is calculated from the cabinet assigned loss (CAL).

[konrado5]

What is radio frequency interference protection? Disabling some tones?

[burakkucat]

What is radio frequency interference protection? Disabling some tones?

I would suspect that you are correct. But as I have no knowledge of any of the FritzBoxes perhaps D*Parrot could explain, please?

[DeluxeParrot]

That is the effect of the DSPBO, required so as not to "swamp" exchange based services, and is calculated from the cabinet assigned loss (CAL).

Ok I see. Protecting the folks on other product types.

What is radio frequency interference protection? Disabling some tones?

It appears the Fritz!Box can automatically detect some radio transmitter interference and can take action, presumably by lowering the number of bits assigned to the affected frequencies, giving a slower speed but more stable line. From This help page:

Under some circumstances radio transmitters located nearby can interfere with DSL communication (RFI: Radio Frequency Interference). This normally will be detected automatically by the FRITZ!Box. If this identification does not work correctly or if an additional source of interference appears, you can move this control step by step toward "Maximum stability" to improve the DSL connection.