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[tims20]

As part of my continuing battle to find out what's going on with our FTTC I've now binned an ASUS DSL-68U which seems to have been responsible for frequent line drops in favour of a trusty VMG1312-B10A along with DSLStats to try and figure out what's going on.

I need to get the ISP to request a DLM reset as with speeds down to 24Mb/s from 37Mb/s and SNR up at 9.6 vs a previous steady 3, it seems that DLM has rather kicked in thanks to the Asus, but the FEC error chart rather caught my eye - attached.

Downstream FEC seems to be sat at a steady 200+k per minute, with a handful of upstream FEC logged.
In the 5h 30m the B10A has been on our line, it has recorded 9,073,458 downstream FEC vs 26.4 upstream.

These feel a little high to me... ?

Can anyone advise on what other stats I should be checking to help establish a cause or next steps? Would rather diagnose what we can before rushing ahead with a DLM reset if there's an underlying problem that needs fixing.

Thanks for your help!
Tim
 

[mofa2020]

As I read here before that G.INP is not working anymore on ASUS dsl-68U which means that interleaving would increase, ping goes higher and lower sync. rate, yet maybe the line would not be stable using interleaving alone if it is a bit noisy... keep the ASUS aside and post the VMG1312-B10A line stats.

[tims20]

The ASUS has been consigned to the bin - couldn't hold a connection for more than an hour or two at best.
Current stats from the VMG1312:

====================================================================================
    VDSL Training Status:   Showtime
                    Mode:   VDSL2 Annex B
            VDSL Profile:   Profile 17a
                G.Vector:   Disable
            Traffic Type:   PTM Mode
             Link Uptime:   0 day: 6 hours: 49 minutes
====================================================================================
       VDSL Port Details       Upstream         Downstream
               Line Rate:      7.025 Mbps       24.998 Mbps
    Actual Net Data Rate:      7.026 Mbps       24.999 Mbps
          Trellis Coding:         ON                ON
              SNR Margin:        6.1 dB            8.5 dB
            Actual Delay:          0 ms              0 ms
          Transmit Power:        3.6 dBm          12.4 dBm
           Receive Power:      -16.5 dBm         -12.2 dBm
              Actual INP:       42.0 symbols      57.0 symbols
       Total Attenuation:        0.0 dB          26.2 dB
Attainable Net Data Rate:      7.026 Mbps       34.157 Mbps
====================================================================================
  VDSL Band Status        U0      U1      U2      U3      U4      D1      D2      D3
  Line Attenuation(dB):    8.5    46.0     N/A     N/A     N/A    20.8    56.9    86.8   
Signal Attenuation(dB):    8.5    45.5     N/A     N/A     N/A    23.6    56.5     N/A   
        SNR Margin(dB):    6.0    6.1     N/A     N/A     N/A    8.1    9.4     N/A   
         TX Power(dBm):   -8.1    3.3     N/A     N/A     N/A    11.3    6.1     N/A   
====================================================================================

            VDSL Counters

           Downstream        Upstream
Since Link time = 49 min 15 sec
FEC:      43151938      248
CRC:      3      0
ES:      1      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Latest 15 minutes time = 4 min 44 sec
FEC:      842042      11
CRC:      0      0
ES:      0      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Previous 15 minutes time = 15 min 0 sec
FEC:      2537422      0
CRC:      0      0
ES:      0      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Latest 1 day time = 6 hours 49 min 44 sec
FEC:      43151938      248
CRC:      3      0
ES:      1      0
SES:      0      0
UAS:      29      29
LOS:      0      0
LOF:      0      0
LOM:      0      0
Previous 1 day time = 0 sec
FEC:      0      0
CRC:      0      0
ES:      0      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Total time = 6 hours 49 min 44 sec
FEC:      43151938      248
CRC:      3      0
ES:      1      0
SES:      0      0
UAS:      29      29
LOS:      0      0
LOF:      0      0
LOM:      0      0
====================================================================================

                 

[j0hn]

Your line is capped/banded at 25Mb.

I regularly received 100,000 FEC/min on my line.
Homeplugs/Powerline adapters increased my FEC count considerably.

[tims20]

Your line is capped/banded at 25Mb.

I regularly received 100,000 FEC/min on my line.
Homeplugs/Powerline adapters increased my FEC count considerably.

Thanks - once the line's been stable for a day or two I'll ask the ISP to reset DLM.
Good thought about Homeplugs; have one plugged in right next to the master socket. Will remove that and see what happens!

[burakkucat]

Good thought about Homeplugs; have one plugged in right next to the master socket. Will remove that and see what happens!

Ah . . .

[tims20]

Ah . . .

 

Yep. The homeplug only serves to give our NAS internet access along with (now) access to the B10A for DSLStats. Have a mini wifi bridge arriving tomorrow to solve that problem so shall see what happens with FEC.

[tims20]

Pulled the homeplugs out of our setup this morning, replacing with a simple TP Link wifi bridge instead...

Safe to say those were the cause of the crazy FEC error count.
Instant drop from a steady 200k+ FEC per minute to the occasional burst of 20 or 30.

Guessing that's not going to do any harm!

[underzone]

Well done, great result!

This thread should now be renamed 'Never use HomePlugs' and stickied 

[j0hn]

Pulled the homeplugs out of our setup this morning, replacing with a simple TP Link wifi bridge instead...

Safe to say those were the cause of the crazy FEC error count.
Instant drop from a steady 200k+ FEC per minute to the occasional burst of 20 or 30.

Guessing that's not going to do any harm!

I'm bookmarking your post to use as a reference for later. Perfect example of Homeplugs interfering with VDSL.

The DSLStats images show exactly what my homeplugs did to my line in the past.

[tims20]

Well done, great result!

This thread should now be renamed 'Never use HomePlugs' and stickied 

Cheers! Everything looks healthier now, which is a nice step in the right direction with the line remaining up for a solid 28 hours so far since connecting the B10A. Distinct improvement on maybe 4 hours max!
Will request another DLM reset & see what happens next.

Thanks all!

[tims20]

I'm bookmarking your post to use as a reference for later. Perfect example of Homeplugs interfering with VDSL.
The DSLStats images show exactly what my homeplugs did to my line in the past.

The direct impact is quite astounding. Couldn't quite believe the drop when I disconnected the units.. Had to start by checking dslstats was still connected 

[mofa2020]

The direct impact is quite astounding. Couldn't quite believe the drop when I disconnected the units.. Had to start by checking dslstats was still connected 

I would think the same, now it is only a matter of time for DLM to correct things 

[burakkucat]

   Homeplugs/PLAs