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Are regular disconnects expected?

Highlighted
Newbie
Posts: 2
Registered: a month ago

Are regular disconnects expected?

Hi,

Over the last couple of weeks my broadband connection has started droping 2 or 3 times a day, around the same time period each day.  I have been working through the troubleshooter to try and isolate possible causes.  So far I think I can rule out interference from other equipment - turning them on when normall off or off when normally on does not seem to change the pattern of disconnections.

I changed my router to a Vigor 130 modem plus EdgeRouter-X router a couple of months back, from an ancient Billion modem router combo, and I can see more detailed connection details from the modem. Modem firmware is latest and greatest.  The information reported is as follows:

> adsl status
  --------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
   Running Mode            : ADSL2+ Annex A       State                : SHOWTIME
   DS Actual Rate          : 12619000 bps   US Actual Rate       :  1147000 bps
   DS Attainable Rate      : 12680000 bps   US Attainable Rate   :  1148000 bps
   DS Path Mode            :        Fast    US Path Mode         :        Fast
   DS Interleave Depth     :        1       US Interleave Depth  :        1
   NE Current Attenuation  :       34 dB    Cur SNR Margin       :        9  dB
   DS actual PSD           :    19. 9 dB    US actual PSD        :    12. 4  dB
   NE Rcvd Cells           : 19411587       NE Xmitted Cells     :  5493622
   NE CRC Count            :     1064       FE CRC Count         :        0
   NE ES Count             :      846       FE  ES Count         :        0
   Xdsl Reset Times        :        0       Xdsl Link  Times     :       33
   ITU Version[0]          : fe004452       ITU Version[1]       : 41590000
   ADSL Firmware Version   : 05-07-02-08-00-01
   Power Management Mode   : DSL_G997_PMS_L0
   Test Mode               : DISABLE
  -------------------------------- ATU-C Info ---------------------------------
   Far Current Attenuation :       19 dB    Far SNR Margin       :        6  dB
   CO ITU Version[0]       : b5004946       CO ITU Version[1]    : 544e827a
   DSLAM CHIPSET VENDOR    : < IFTN >

The pattern I am noticing each day is that at 5pm (to the minute!) the downstream/DS attainable rate starts quickly dropping to below the actual rate, often by 1Mbps below what was being reported during the day. At the same time the NE CRC/ES count to start to climb and over the next few hours the connection drops and retrains at a lower rate.  The attainable rate continues to drop and the same thing often happens again with a further disconnect during the evening.  Then during the night the attainable rate increases and early in the morning the connection drops and retrains to a higher rate, and the whole thing repeats at 5pm the next day when the attainable rate drops again.

Everything else is stable - attenuation, Cur SNR margin, and PSDs.  I have seen a count of FE error counts, of 1, which clear after an hour or so.  The only things that change are the attainable rates and the NE counts.

So it seems I have two processes interacting here - the drop in attainable rate each evening at 5pm, and the NE error counts (in the above example this is around 2 hours after the last retrain - no idea if the counts are low, high, or to be expected!)  Sometimes the error count is low, a few 10s over an hour, but then starts to shoot up to a few 100s per hour.

I have a log of the connection drops and they seem to happen at relatively fixed periods between each other, which sounds more like the far end forcing the line drop and not my modem.

Based on all this does this sound like an issue my side of the master socket or on BTs side of things?

TIA

Mike
1 REPLY 1
Highlighted
Newbie
Posts: 2
Registered: a month ago

Re: Are regular disconnects expected?

As expected there was a drop Thursday evening and a retrain to a lower rate of ~11.5Mbps. Since then no more drops (Fridays always seem quieter for some reason).  Here are the stats for this morning (Saturday):

> show adsl
  --------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
   Running Mode            : ADSL2+ Annex A       State                : SHOWTIME
   DS Actual Rate          : 11554000 bps   US Actual Rate       :  1159000 bps
   DS Attainable Rate      : 12548000 bps   US Attainable Rate   :  1156000 bps
   DS Path Mode            :        Fast    US Path Mode         :        Fast
   DS Interleave Depth     :        1       US Interleave Depth  :        1
   NE Current Attenuation  :       35 dB    Cur SNR Margin       :        8  dB
   DS actual PSD           :    19. 9 dB    US actual PSD        :    12. 4  dB
   NE Rcvd Cells           : 303000013       NE Xmitted Cells     : 10050672
   NE CRC Count            :     3757       FE CRC Count         :        0
   NE ES Count             :     2289       FE  ES Count         :        0
   Xdsl Reset Times        :        0       Xdsl Link  Times     :       34
   ITU Version[0]          : fe004452       ITU Version[1]       : 41590000
   ADSL Firmware Version   : 05-07-02-08-00-01
   Power Management Mode   : DSL_G997_PMS_L0
   Test Mode               : DISABLE
  -------------------------------- ATU-C Info ---------------------------------
   Far Current Attenuation :       19 dB    Far SNR Margin       :        6  dB
   CO ITU Version[0]       : b5004946       CO ITU Version[1]    : 544e827a
   DSLAM CHIPSET VENDOR    : < IFTN >

As usual the only things to vary are the attainable rate and SNR Margin. Since I changed the microfilter on the master socket (no extensions used) the attainable rate has settled to varying between 12.5Mbps during the day and 12.1Mbps in the evening, The SNR Margin seems to vary between 9 during the day and 7 at night.

FTR the previous microfilter (tail-less, one of those T shaped ones) had been in use for best part of a decade. As part of the troubleshooter I tried a new tailed microfilter but rates dropped to 9MBps. Found another unused tail-less one in a box which seems more stable and I have been using that for the last few days - maybe new better electronics has improved things, maybe the friction on the socket connection has improved the signal quality (the socket is decades old).

This kinda looks like a new connection training period over a couple of weeks.  I have been on broadband for can't think how long. I replaced my modem 3 months ago so it should have settled down by now if that had made a difference, so I am a surprised that could have kicked in.

Will keep an eye on things but it now looks stable, happy with the current rate, error rate is low (90/hr), and low latency (ping times of 12ms). If it was just a hicup between the dslam and microfilter then vdsl here I come!

Mike