Topic: Power cut resulted in a higher sync speed? (Read 2486 times)

Jon21 · « **on:** May 31, 2018, 05:05:42 PM »

Not really an issue as such. Had a power cut in the last 15 minutes which lasted 30 seconds, if that. The line has re-synced at a higher rate but the SNR margin seems low?

---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 71590000 bps US Actual Rate : 17913000 bps
DS Attainable Rate : 62942136 bps US Attainable Rate : 15794676 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 20 dB Cur SNR Margin : 2 dB
DS actual PSD : 6. 8 dB US actual PSD : 12. 6 dB
NE CRC Count : 15 FE CRC Count : 258
NE ES Count : 12 FE ES Count : 196
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-06-0D-01-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 27 dB Far SNR Margin : 4 dB
CO ITU Version[0] : b5004946 CO ITU Version[1] : 544ed086
DSLAM CHIPSET VENDOR : < IFTN >

It had been sitting between 5-6dB since the new line was installed. Is it anything to be concerned about?

On an ECI cabinet, didn't think the SNR value went that low unless there was a problem?

sotonsam · « **Reply #1 on:** May 31, 2018, 05:12:04 PM »

Was it a 'wide area' powercut, or just you?

If it was a wide area powercut, the chances are that you connected before other people - so you had a reduction in the effects of crosstalk.

I had it a year or so ago, didn't last long though - give it a week or so!

Weaver · « **Reply #2 on:** May 31, 2018, 05:18:34 PM »

Yes, same here. See https://forum.kitz.co.uk/index.php/topic,18807.0.html

If there is a future power cut and I turn on my generator I can then enjoy the lack of crosstalk for a while while all the neighbours are still off. Could be an interesting experiment.

Jon21 · « **Reply #3 on:** May 31, 2018, 05:44:40 PM »

Quote from: sotonsam on May 31, 2018, 05:12:04 PM

Was it a 'wide area' powercut, or just you?

If it was a wide area powercut, the chances are that you connected before other people - so you had a reduction in the effects of crosstalk.

I had it a year or so ago, didn't last long though - give it a week or so!

Not sure how wide an area it was, did result in the local mobile mast going down, or at least there being no mobile signal for a few minutes. House alarms etc going off as well.

Would the lack of crosstalk affect the SNR margin, if the modem synced before other people?

burakkucat · « **Reply #4 on:** May 31, 2018, 06:29:32 PM »

Quote from: Jon21 on May 31, 2018, 05:44:40 PM

Would the lack of crosstalk affect the SNR margin, if the modem synced before other people?

If your modem re-trained and synchronised before the other nearby circuits reached that state then your modem will, for a short while, be operating at the default target SNRM with an increased synchronisation speed. As the other circuits "come back", the increasing crosstalk will depress your circuit's SNRM without affecting the synchronisation speed. The end result is exactly that which you have reported.

ktz392837 · « **Reply #5 on:** May 31, 2018, 11:21:51 PM »

There are many variables but it also shows how fast your line could be if Ginp and 3db was available on ECI cabinets (possibly even faster than the 71Mbs you temporarily have now).

I truly hate my ECI cabinet I wish I was originally on the BDUK rollout and not the Commercial rollout as I would have a Huwaei cabinet instead.

Jon21 · « **Reply #6 on:** June 01, 2018, 10:42:05 AM »

Thanks for the replies, learnt something new from them

I did resync the modem yesterday. Was the possibility of some thunderstorms, so thought I’d rather have the extra margin rather than the speed to help keep the connection stable. Storms didn’t happen around here though. Back to the “normal” sync speed of 64Mb now with a 6dB margin.

Have had a drop in latency from around 9pm yesterday but suspect that was A&A tinkering with their network.

sotonsam · « **Reply #7 on:** June 01, 2018, 12:51:30 PM »

I think your sync speed is pretty good for your attenuation.

I have a 14db attenuation on my BT line and I struggle to get above 55mb these days. Still fighting with BT to try and get some support on it, as I'm below what they call my 'guaranteed' minimum!

My AAISP line is only a little better, I have 13db attenuation with this one, but can’t really get above 63Mb.

Ixel · « **Reply #8 on:** June 01, 2018, 02:07:31 PM »

If you have a DrayTek, and judging by the way the stats are output I believe you do, then you can potentially squeeze a little more speed out of your downstream. As long as the errored seconds are low enough to allow for it that is. One of my lines performs exceptionally better than the other, which allows me to reduce the target SNRM offset (currently -10, which is 5 dB). I've had the offset as low as -2.5 dB (or -25, which makes the target SNRM actually 3.5 dB) for my good performing line of the two lines I have, but nudged it back up recently because of the storms but now they've gone.

"vdsl snr [delta]"
"vdsl savecfg"

Where [delta] can be between -50 to 50 and is represented as dB/10. For example, a value of -20 would decrease the downstream SNRM target by -2.0 dB.

If you do this then I suggest doing it in small increments at most once a day and monitoring for stability, by either -5 or -10 (-0.5 dB or -1.0 dB).

Code: [Select]

> vdsl status

  ---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
   Running Mode            :      17A       State                : SHOWTIME
   DS Actual Rate          : 65239000 bps   US Actual Rate       : 15725000 bps
   DS Attainable Rate      : 65604696 bps   US Attainable Rate   : 15955998 bps
   DS Path Mode            :        Fast    US Path Mode         :        Fast 
   DS Interleave Depth     :        1       US Interleave Depth  :        1 
   NE Current Attenuation  :       16 dB    Cur SNR Margin       :        5  dB
   DS actual PSD           :     6. 7 dB    US actual PSD        :    12. 7  dB
   NE CRC Count            :      464       FE CRC Count         :     5650
   NE ES Count             :      366       FE  ES Count         :     4566
   Xdsl Reset Times        :        0       Xdsl Link  Times     :        2
   ITU Version[0]          : 00000000       ITU Version[1]       : 00000000
   VDSL Firmware Version   : 05-07-06-0D-01-07   [with Vectoring support] 
   Power Management Mode   : DSL_G997_PMS_L0 
   Test Mode               : DISABLE 
  -------------------------------- ATU-C Info ---------------------------------
   Far Current Attenuation :       22 dB    Far SNR Margin       :        6  dB
   CO ITU Version[0]       : b5004946       CO ITU Version[1]    : 544ed086
   DSLAM CHIPSET VENDOR    : < IFTN >
> vdsl snr

Usage:
vdsl snr [delta]
  delta: SNR margin delta. The SNR margin delta should range from -50 to 50.
  delta=1 means 0.1dB.
  Current VDSL SNR Margin is 5 dB.
  Current VDSL SNR Margin delta setting is -10.

Jon21 · « **Reply #9 on:** June 01, 2018, 02:33:41 PM »

Quote from: Ixel on June 01, 2018, 02:07:31 PM

If you have a DrayTek, and judging by the way the stats are output I believe you do, then you can potentially squeeze a little more speed out of your downstream. As long as the errored seconds are low enough to allow for it that is. One of my lines performs exceptionally better than the other, which allows me to reduce the target SNRM offset (currently -10, which is 5 dB). I've had the offset as low as -2.5 dB (or -25, which makes the target SNRM actually 3.5 dB) for my good performing line of the two lines I have, but nudged it back up recently because of the storms but now they've gone.

"vdsl snr [delta]"
"vdsl savecfg"

Where [delta] can be between -50 to 50 and is represented as dB/10. For example, a value of -20 would decrease the downstream SNRM target by -2.0 dB.

If you do this then I suggest doing it in small increments at most once a day and monitoring for stability, by either -5 or -10 (-0.5 dB or -1.0 dB).

Code: [Select]
> vdsl status ---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) ----------- Running Mode : 17A State : SHOWTIME DS Actual Rate : 65239000 bps US Actual Rate : 15725000 bps DS Attainable Rate : 65604696 bps US Attainable Rate : 15955998 bps DS Path Mode : Fast US Path Mode : Fast DS Interleave Depth : 1 US Interleave Depth : 1 NE Current Attenuation : 16 dB Cur SNR Margin : 5 dB DS actual PSD : 6. 7 dB US actual PSD : 12. 7 dB NE CRC Count : 464 FE CRC Count : 5650 NE ES Count : 366 FE ES Count : 4566 Xdsl Reset Times : 0 Xdsl Link Times : 2 ITU Version[0] : 00000000 ITU Version[1] : 00000000 VDSL Firmware Version : 05-07-06-0D-01-07 [with Vectoring support] Power Management Mode : DSL_G997_PMS_L0 Test Mode : DISABLE -------------------------------- ATU-C Info --------------------------------- Far Current Attenuation : 22 dB Far SNR Margin : 6 dB CO ITU Version[0] : b5004946 CO ITU Version[1] : 544ed086 DSLAM CHIPSET VENDOR : < IFTN > > vdsl snr Usage: vdsl snr [delta] delta: SNR margin delta. The SNR margin delta should range from -50 to 50. delta=1 means 0.1dB. Current VDSL SNR Margin is 5 dB. Current VDSL SNR Margin delta setting is -10.

Cheers Ixel, will perhaps give it a go at some point. It is a Draytek modem, a Vigor 130.

Slightly unrelated but seems as though TTB are having some issues at the moment. Status update has been put on A&A’s page. Can see the minimum latency changing on my TBB monitor.

johnson · « **Reply #10 on:** June 01, 2018, 02:44:41 PM »

Quote from: Jon21 on June 01, 2018, 02:33:41 PM

Slightly unrelated but seems as though TTB are having some issues at the moment.

Sorry for OT but I just had my PPP session drop with TTB, have you had similar?

Jon21 · « **Reply #11 on:** June 01, 2018, 03:02:27 PM »

Quote from: johnson on June 01, 2018, 02:44:41 PM

Sorry for OT but I just had my PPP session drop with TTB, have you had similar?

Not at the time of your post. It may of dropped around 2pm ish going by the TBB graph, but I wasn’t around at the time to check.

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Author Topic: Power cut resulted in a higher sync speed? (Read 2486 times)

Jon21

Power cut resulted in a higher sync speed?

sotonsam

Re: Power cut resulted in a higher sync speed?

Weaver

Re: Power cut resulted in a higher sync speed?

Jon21

Re: Power cut resulted in a higher sync speed?

burakkucat

Re: Power cut resulted in a higher sync speed?

ktz392837

Re: Power cut resulted in a higher sync speed?

Jon21

Re: Power cut resulted in a higher sync speed?

sotonsam

Re: Power cut resulted in a higher sync speed?

Ixel

Re: Power cut resulted in a higher sync speed?

Jon21

Re: Power cut resulted in a higher sync speed?

johnson

Re: Power cut resulted in a higher sync speed?

Jon21

Re: Power cut resulted in a higher sync speed?