BB drop outs!!!

This afternoon my BB connection dropped out and reconnected 13 times within
a 5 minute period between 12:43:17 and 12:47:34. These drop-outs led to
the following changes in synch rate (the SNR relating to each new synch rate
is contained within the relevant parentheses)

Synch rate 6336(8.2dB) to 6304 (8.1dB) to 6208 (9.2dB) to 6272 (9.6dB) to
6336 (8.4dB) to 6272(6.8dB) to 6208 (3.4dB) to 4480 (12.3dB) to 4672
(12.9dB) to 4096 (10.5dB) to 4032 (4.9dB) to 5888 (4.9dB) to 5120 (3.6dB)
and to 5088 (8.7dB).

I rebooted the router at 13:28:36 and recovered synch rate to 6368 (9.8dB)
but a further disconnection at 14:20:18 dropped the synch rate to 4846
(15.6dB).

A further router reboot at 15:30:59 realised a synch rate 4928 (15.7dB)
which appears to have remained stable since then. It is now 18:40

So it appears after all the excitement that my target SNR has been upped
from 9db, (where it has been set and has performed satisfactorily for at
least 12 months), to 15dB.

My questions are these:
1 Has anyone any idea as to what produced the extremely erratic behaviour
around 12:45?
NB: I can't think of anything here that could account for it.
2 If my connection now remains stable will the target SNR be automatically
reduced again or
3 will I have to request a reduction of target SNR when the connection has
proved to be stable again?


--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland

"Flyiñg Ñuñ 2°°8 +" wrote:

> This afternoon my BB connection dropped out and reconnected 13 times within
> a 5 minute period between 12:43:17 and 12:47:34. These drop-outs led to
> the following changes in synch rate (the SNR relating to each new synch rate
> is contained within the relevant parentheses)
>
> Synch rate 6336(8.2dB) to 6304 (8.1dB) to 6208 (9.2dB) to 6272 (9.6dB) to
> 6336 (8.4dB) to 6272(6.8dB) to 6208 (3.4dB) to 4480 (12.3dB) to 4672
> (12.9dB) to 4096 (10.5dB) to 4032 (4.9dB) to 5888 (4.9dB) to 5120 (3.6dB)
> and to 5088 (8.7dB).
>
> I rebooted the router at 13:28:36 and recovered synch rate to 6368 (9.8dB)
> but a further disconnection at 14:20:18 dropped the synch rate to 4846
> (15.6dB).
>
> A further router reboot at 15:30:59 realised a synch rate 4928 (15.7dB)
> which appears to have remained stable since then. It is now 18:40
>
> So it appears after all the excitement that my target SNR has been upped
> from 9db, (where it has been set and has performed satisfactorily for at
> least 12 months), to 15dB.
>
> My questions are these:
> 1 Has anyone any idea as to what produced the extremely erratic behaviour
> around 12:45?

Engineers fiddling with jumpers ?


> NB: I can't think of anything here that could account for it.
> 2 If my connection now remains stable will the target SNR be automatically
> reduced again or
> 3 will I have to request a reduction of target SNR when the connection has
> proved to be stable again?

Once it's stable and the SNR margin is still that high then yes, contacting your
ISP is the answer. It's not actually SNR btw. It's the 'excess' SNR below which
operation will cease to function. Mine's hovering between 4.9 and 6.1 dB right
now and I can get a full 8128 kbps sync (line attenuation down 27.7dB).

Graham

Ato_Zee wrote:
>> My questions are these:
>> 1 Has anyone any idea as to what produced the extremely erratic
>> behaviour around 12:45?
>> NB: I can't think of anything here that could account for it.
> No, any Openreach work nearby?
> Maybe running Krone tool along Krone strip in local JBox to try and
> fix an intermittent, triggering another intermittent.

Is it possible that transients induced on my line from faulty electrical
equipment elsewhere could cause it? I suspect that there is something
producing electrical interference (quite recently started) since I get audio
and video interference on BBC1 (analogue terrestrial) but no other channel
most days now. I suspect there's some faulty device somewhere nearby that
comes into operation when there's a cold spell (CH pumps or the like) .

>> 2 If my connection now remains stable will the target SNR be
>> automatically reduced again
> Should be if everything is rniing stable again, but it can
> take over a week, and no guarantee.

I know that IP Profile is restored in that sort of time scale, but not SNR.
I'll try waiting a bit then.

>> 3 will I have to request a reduction of target SNR when the
>> connection has proved to be stable again?

> If you have a responsive ISP they may get your target reduced,
> if your line isn't stable that won't hold for long.

Yep my ISP have done that for me quite some time ago. Apparently the manual
adjustment is quite simple. It's persuading BT to do it that takes all the
time and effort.

> If your router supports it try resetting your SNR target with
> DMT tool, but again if your line isn't stable it won't hold.
>
Unfortunately my router doesn't support the DMT tool.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland

Eeyore wrote:
> "Flyiñg Ñuñ 2°°8 +" wrote:
>
>> This afternoon my BB connection dropped out and reconnected 13 times
>> within a 5 minute period between 12:43:17 and 12:47:34. These
>> drop-outs led to the following changes in synch rate (the SNR
>> relating to each new synch rate is contained within the relevant
>> parentheses)
>>
>> Synch rate 6336(8.2dB) to 6304 (8.1dB) to 6208 (9.2dB) to 6272
>> (9.6dB) to 6336 (8.4dB) to 6272(6.8dB) to 6208 (3.4dB) to 4480
>> (12.3dB) to 4672 (12.9dB) to 4096 (10.5dB) to 4032 (4.9dB) to 5888
>> (4.9dB) to 5120 (3.6dB) and to 5088 (8.7dB).
>>
>> I rebooted the router at 13:28:36 and recovered synch rate to 6368
>> (9.8dB) but a further disconnection at 14:20:18 dropped the synch
>> rate to 4846 (15.6dB).
>>
>> A further router reboot at 15:30:59 realised a synch rate 4928
>> (15.7dB) which appears to have remained stable since then. It is now
>> 18:40
>>
>> So it appears after all the excitement that my target SNR has been
>> upped from 9db, (where it has been set and has performed
>> satisfactorily for at least 12 months), to 15dB.
>>
>> My questions are these:
>> 1 Has anyone any idea as to what produced the extremely erratic
>> behaviour around 12:45?
>
> Engineers fiddling with jumpers ?
>
>
>> NB: I can't think of anything here that could account for it.
>> 2 If my connection now remains stable will the target SNR be
>> automatically reduced again or
>> 3 will I have to request a reduction of target SNR when the
>> connection has proved to be stable again?
>
> Once it's stable and the SNR margin is still that high then yes,
> contacting your ISP is the answer. It's not actually SNR btw. It's
> the 'excess' SNR below which operation will cease to function. Mine's
> hovering between 4.9 and 6.1 dB right now and I can get a full 8128
> kbps sync (line attenuation down 27.7dB).
>
> Graham
>
Thanks Graham. The actual running SNR, as I call it, used to vary between
8.5dB and 10dB before yesterday afternoon's little episode. It's now
hovering around 15dB. The figures I quoted are those that the router log
quotes as the connection is being set up.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland

Martin² wrote:
> Join the clan...
> I have such episodes every 3-4 months, and less severe ones every
> couple of weeks.
> Previously rebooting the router would fairly quickly bring the SNR
> down to normal 6dB.
> However, in May this year it got stuck on 15dB, because BT changed
> their DLM program.
> Took me months to get ISP to get BT to bring it down to 12dB, and same
> hassle again to persuade them that it will work at 9dB.
> I KNOW it will work most of the time at 6dB, but BT won't let me :-(
> Used to get 2.8Mb/s, now I struggle to hold on to ~1.7Mb/s.
> Not happy about it, but stuck with BT line, there is no alternative !
> Regards,
> Martin

I had an episode about 18 months ago where BT upped the SNR from 9 to 12dB.
After several weeks discussing the problem, my ISP persuaded them to revert
to 9 dB and everything was fine since then until this recent event. The SNR
is now at 15dB and synch rate down at 4700 from the usual ~ 6400. IOP
Profile has been reduced from 5500 to 3500, so within 48 hours my download
speeds are down from around 5200 to 3300 kbps. Unfortunately there appear
to be lots of crc errors occurring even at 15 dB so a change back to 9dB may
not be on the cards this time.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland

"Martin²" wrote:

> Join the clan...
> I have such episodes every 3-4 months, and less severe ones every couple of
> weeks.
> Previously rebooting the router would fairly quickly bring the SNR down to
> normal 6dB.
> However, in May this year it got stuck on 15dB, because BT changed their DLM
> program.
> Took me months to get ISP to get BT to bring it down to 12dB, and same
> hassle again to persuade them that it will work at 9dB.
> I KNOW it will work most of the time at 6dB, but BT won't let me :-(
> Used to get 2.8Mb/s, now I struggle to hold on to ~1.7Mb/s.
> Not happy about it, but stuck with BT line, there is no alternative !

Hmmmm. Never had this specific problem but Idnet got BT to change the latency
back to fast from interleaved once for me.

Graham

Flyiñg Ñuñ 2°°8 + wrote:
> Martin² wrote:
>> Join the clan...
>> I have such episodes every 3-4 months, and less severe ones every
>> couple of weeks.
>> Previously rebooting the router would fairly quickly bring the SNR
>> down to normal 6dB.
>> However, in May this year it got stuck on 15dB, because BT changed
>> their DLM program.
>> Took me months to get ISP to get BT to bring it down to 12dB, and
>> same hassle again to persuade them that it will work at 9dB.
>> I KNOW it will work most of the time at 6dB, but BT won't let me :-(
>> Used to get 2.8Mb/s, now I struggle to hold on to ~1.7Mb/s.
>> Not happy about it, but stuck with BT line, there is no alternative !
>> Regards,
>> Martin
>
> I had an episode about 18 months ago where BT upped the SNR from 9 to
> 12dB. After several weeks discussing the problem, my ISP persuaded
> them to revert to 9 dB and everything was fine since then until this
> recent event. The SNR is now at 15dB and synch rate down at 4700
> from the usual ~ 6400. IOP Profile has been reduced from 5500 to
> 3500, so within 48 hours my download speeds are down from around
> 5200 to 3300 kbps. Unfortunately there appear to be lots of crc
> errors occurring even at 15 dB so a change back to 9dB may not be on
> the cards this time.
Even got a couple of crc errors on upstream today. Never ever seen crc
errors there before, that's always been so stable.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland

In message <(E-Mail Removed)>, Flyiñg Ñuñ 2°°8 +
<(E-Mail Removed)> writes
>Ato_Zee wrote:
>>> My questions are these:
>>> 1 Has anyone any idea as to what produced the extremely erratic
>>> behaviour around 12:45?
>>> NB: I can't think of anything here that could account for it.
>> No, any Openreach work nearby?
>> Maybe running Krone tool along Krone strip in local JBox to try and
>> fix an intermittent, triggering another intermittent.
>
>Is it possible that transients induced on my line from faulty electrical
>equipment elsewhere could cause it? I suspect that there is something
>producing electrical interference (quite recently started) since I get audio
>and video interference on BBC1 (analogue terrestrial) but no other channel
>most days now. I suspect there's some faulty device somewhere nearby that
>comes into operation when there's a cold spell (CH pumps or the like) .
>
>>> 2 If my connection now remains stable will the target SNR be
>>> automatically reduced again
>> Should be if everything is rniing stable again, but it can
>> take over a week, and no guarantee.
>
>I know that IP Profile is restored in that sort of time scale, but not SNR.
>I'll try waiting a bit then.
>
>>> 3 will I have to request a reduction of target SNR when the
>>> connection has proved to be stable again?
>
>> If you have a responsive ISP they may get your target reduced,
>> if your line isn't stable that won't hold for long.
>
>Yep my ISP have done that for me quite some time ago. Apparently the manual
>adjustment is quite simple. It's persuading BT to do it that takes all the
>time and effort.
>
>> If your router supports it try resetting your SNR target with
>> DMT tool, but again if your line isn't stable it won't hold.
>>
>Unfortunately my router doesn't support the DMT tool.
I had a similar incident in July following a big electrical storm in the
area. The exchange reset my target SNR to 12dB. Plusnet arranged to
reset it back down to 6dB which worked fine, but a couple of weeks later
it wound itself back up to 15dB. The impression I got (from reading
various forums (fora?)) was that BT had upgraded the monitoring to take
into consideration the error rates on the line as well as simply
dropouts.

My line is longish, and almost all overhead - it suffers from some level
of burst interference ( probably from the local agricultural machinery
repair shop - an arc welder?) and a significant day/night fluctuation
(MW RF pickup?). It is long term stable at sync speeds around 6300 with
SNR varying from 5db at night to 8-9dB during the day. At over 5dB error
rates are very low (0,1 or 2 ES per 15 minute period). At night the rate
can rise to 6-10 ES per minute when the SNR drops below 5dB)

I resorted to an ex Sky DG834GT router (£12 off Ebay) and the DGTeam
firmware to let me manipulate the SNR Target. Turning the target down to
40% allowed me to resync at around 6300 and all was well.

Recently ( so 2-3 months of stable running ) my line appears to have
reset its target SNR to 6db. I only noticed because the router resync'd
during the day ( somebody dropped the arc welder?) to 7800ish with a
SNR of 3dB - at which point the error rates were significant!! I now run
at 80% target so that any resets during the night get me above 6240 and
maintain the BRAS profile at 5500.

So it looks as if the exchange will reset SNR - but it takes a long
time. I would ask your ISP in the first place - secondly get a router
that allows you to control things.
--
Peter R Cook

Invalid wrote:
> In message <(E-Mail Removed)>, Flyiñg Ñuñ 2°°8 +
> <(E-Mail Removed)> writes
>> Ato_Zee wrote:
>>>> My questions are these:
>>>> 1 Has anyone any idea as to what produced the extremely erratic
>>>> behaviour around 12:45?
>>>> NB: I can't think of anything here that could account for it.
>>> No, any Openreach work nearby?
>>> Maybe running Krone tool along Krone strip in local JBox to try and
>>> fix an intermittent, triggering another intermittent.
>>
>> Is it possible that transients induced on my line from faulty
>> electrical equipment elsewhere could cause it? I suspect that
>> there is something producing electrical interference (quite recently
>> started) since I get audio and video interference on BBC1 (analogue
>> terrestrial) but no other channel most days now. I suspect there's
>> some faulty device somewhere nearby that comes into operation when
>> there's a cold spell (CH pumps or the like) .
>>>> 2 If my connection now remains stable will the target SNR be
>>>> automatically reduced again
>>> Should be if everything is rniing stable again, but it can
>>> take over a week, and no guarantee.
>>
>> I know that IP Profile is restored in that sort of time scale, but
>> not SNR. I'll try waiting a bit then.
>>
>>>> 3 will I have to request a reduction of target SNR when the
>>>> connection has proved to be stable again?
>>
>>> If you have a responsive ISP they may get your target reduced,
>>> if your line isn't stable that won't hold for long.
>>
>> Yep my ISP have done that for me quite some time ago. Apparently
>> the manual adjustment is quite simple. It's persuading BT to do it
>> that takes all the time and effort.
>>
>>> If your router supports it try resetting your SNR target with
>>> DMT tool, but again if your line isn't stable it won't hold.
>>>
>> Unfortunately my router doesn't support the DMT tool.
> I had a similar incident in July following a big electrical storm in
> the area. The exchange reset my target SNR to 12dB. Plusnet arranged
> to reset it back down to 6dB which worked fine, but a couple of weeks
> later it wound itself back up to 15dB. The impression I got (from
> reading various forums (fora?)) was that BT had upgraded the
> monitoring to take into consideration the error rates on the line as
> well as simply dropouts.
>
> My line is longish, and almost all overhead - it suffers from some
> level of burst interference ( probably from the local agricultural
> machinery repair shop - an arc welder?) and a significant day/night
> fluctuation (MW RF pickup?). It is long term stable at sync speeds
> around 6300 with SNR varying from 5db at night to 8-9dB during the
> day. At over 5dB error rates are very low (0,1 or 2 ES per 15 minute
> period). At night the rate can rise to 6-10 ES per minute when the
> SNR drops below 5dB)
> I resorted to an ex Sky DG834GT router (£12 off Ebay) and the DGTeam
> firmware to let me manipulate the SNR Target. Turning the target down
> to 40% allowed me to resync at around 6300 and all was well.
>
> Recently ( so 2-3 months of stable running ) my line appears to have
> reset its target SNR to 6db. I only noticed because the router
> resync'd during the day ( somebody dropped the arc welder?) to
> 7800ish with a SNR of 3dB - at which point the error rates were
> significant!! I now run at 80% target so that any resets during the
> night get me above 6240 and maintain the BRAS profile at 5500.
>
> So it looks as if the exchange will reset SNR - but it takes a long
> time. I would ask your ISP in the first place - secondly get a router
> that allows you to control things.

Thanks for that Invalid. Unfortunately it appears that there is some new
source of interference affdting my line now. So far today (3½ hours since
reboot) I've had 103 crc errors downstream and 2 crc errors upstream. Never
seen a crc error upstream before. SNR downstream is currently varying
between 16 dB and 17dB - a far cry from the 12 months + at between 9 and 10.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland

Ato_Zee wrote:
>> Is it possible that transients induced on my line from faulty
>> electrical equipment elsewhere could cause it? I suspect that
>> there is something producing electrical interference (quite recently
>> started) since I get audio
>> and video interference on BBC1 (analogue terrestrial) but no other
>> channel
>>
>> most days now. I suspect there's some faulty device somewhere
>> nearby that
>> comes into operation when there's a cold spell (CH pumps or the
>> like) .
>
> Regular transients will reduce you to dialup speeds. You can
> report TV sound and audio interference, but even if they
> investigate, it rarely happens when you want it to; if
> it it is transient it is by definition elusive. A TV screen shot
> showing the interference might help.
> It can be extreme, long rural line, local farrier and farm machinery
> fixer, running an arc welder in his workshop at the end of the lane,
> causing the lights to dim. Or ADSL drop wire resting on mercury street
> light fitting, having slid down to the ambient light sensor. Local
> council having recently replaced light with a taller one.
> More common round now are blinking outside Christmas
> lights with wiring long enough to make a good aerial.
> CH pumps may have associated arc induced
> boiler ignition, and the pumps themselves are a reactive
> load.
> I mentioned DMT tool because it will plot SNR, which
> helps to show if it is isolated transients or long bursts
> of noise, a burst of noise every 4 minutes has a different
> diagnosis than a single spat every half hour, though the
> effects on ADSL are the same; you might be able to
> correlate it with the TV interference. Not to mention
> being able to reset your target SNR.
> As far as I can judge, from experimenting, is that the
> DSLAM algorithm seems to set SNR on the basis of
> a moving average of CRC errors. So it takes a long
> period of quiet running, with low errors, before the
> target is reduced, and if never will be if the noise
> keep re-occuring.
> A complete modem/router swap can sometimes
> cause your SNR to be reset, I think the DSLAM
> interogates on restablishing contact "What standards
> do you support and what sort of modem are you",
> possibly some modem classification exits" Modems
> type A, B, C or whatever.

It's been suggested to me that a BT BUSINESS HUB is set up to be far less
susceptible to this kind of interference, so I was hoping to acquire one
cheaply and give it a go.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°8 +, Mungo Brandybuck of Buckland