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What Just Happened There?

thejudge
Grafter
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Registered: 01-08-2007

What Just Happened There?

All OK until about 17:30, then browsing came to a complete standstill - pages wouldn't load, nothing.
Tracerts were mostly (but not entirely) asterisks.
I tried an ordinary disconnect/connect of the router, but that didn't improve anything (even though I did manage to gateway-jump from pcl-ag02 to another one; can't remember which now, except that it was an -ag02 one).
Finally decided to reboot the router. When it came back up, it seemed to have trouble connecting, but got there in the end...
...except that, whereas I had had a synch speed of around 5.2M before all this happened, it was now synching at only 1.8M.
I've tried rebooting the router three times since, but I still can't get a synch speed over 2.4M.
Anyone else seen something similar this evening?
16 REPLIES
thejudge
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Re: What Just Happened There?

OK, a further reboot has got a resynch at 5.4M, but it still doesn't feel quite right - some laggy browsing, especially to the Portal and Community.
Any thoughts on what might have happened/be happening?
thejudge
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Re: What Just Happened There?

Well that didn't last, did it?
At about 20:50 it did it again - same symptoms as before.
This time, I powered the router off completely for about ten minutes. I replaced the microfilters then powered the router back up.
It seemed to struggle to synch, and then it did, but back down at 2.2Mbps.
Anyone?
Superuser
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Re: What Just Happened There?

Nigel,
This might be related to line noise.  If you dial 17070 option 2, is the line quiet?
thejudge
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Re: What Just Happened There?

Yes, quiet as anything.
Superuser
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Re: What Just Happened There?

Nigel,
Can you please post your router stats?
If you do not mind a bit of technical fiddling, download and install RouterStats from here - http://www.vwlowen.co.uk/internet/files.htm - I suggest watching the SNRM graphs.  If these are not fairly static, it might point to a REIN issue.
thejudge
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Re: What Just Happened There?

I've installed RouterStats, and it's now running. How long should I need to run it for to get a useful level of data?
Superuser
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Re: What Just Happened There?

Hours and hours...
You are looking for unexpected variations in the SNRM which would indicate electrical noise - you might see nothing!  The first attached graph shows the usual night time MW interference plus the noise induced by passing electric trains.  The second attached graph shows no issues.
thejudge
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Re: What Just Happened There?

Looks like I'm going to have to come back to this tomorrow afternoon, then (I can't leave the PC running overnight).
For what it's worth, 25 minutes' running has the SNR at a steady 14dB throughout, with occasional spikes up to 15. But this is with a synch speed of only 2277k.
When I come back to it tomorrow, would it be worth trying a re-synch to a higher speed to see what happens then?
(Historically - that is, in the last 2 to 3 years - if I synch anywhere above about 5.7Mbps, the SNR tends to drop to below 3dB from about 7pm. I have a Netgear DG834, which is the only reason why I can stay connected when that happens).
Superuser
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Re: What Just Happened There?

Nigel,
Can you post your modem stats please.  14dB is high and indicates in itself something is not right.
Kevin
thejudge
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Re: What Just Happened There?

Kevin,
Are these the ones you mean?
I've just noticed something. My downstream attenuation has been 23 db for years. Now it's 42!
Update: the RouterStats graph just dropped right down to zero. before bouncing back up to 14 after about 40 seconds.
Superuser
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Re: What Just Happened There?

Nigel,
That sounds like another disconnect.  The router stars don't look good. Unfortunately the Netgear routers don't tend to report error counts or modulation type.  The US is capped so you might be on a 20CN.
Suggest you proceed with the fault report.
Kevin
thejudge
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Re: What Just Happened There?

Right, this is what happened today.
When I powered up the PC this afternoon about 16:45, the connection was still at about 5.4M (which is where it was late last night), with an SNR of 9dB.
I opened RouterStats and let it run...
...and then five minutes later, the power blipped out.  Angry
When I powered everything back up again, I found that the router had re-synched at 6.8M. This usually means trouble later in the evening, but I let it pass.
The SNR was a steady 4dB, with the odd blip down to 2dB. From about 19:00, this changed to a steady 3dB with the odd drop to 1dB or 0.
I may still have to re-synch later on if the SNR goes negative, as it tends to do at synch speeds above about 5.8M later in the evening. At the moment, however, there's been no repeat of Wednesday evening's problems. Should I take that as indicating that last night was an anomaly which has 'cleared' itself? And should I still be concerned by the attenuation nearly doubling (it's still showing 43dB)?
Community Veteran
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Re: What Just Happened There?

If the downstream line attenuation ever was really 23db, then you should have been getting speeds much higher than 5 or 6 Mb.
(Also, probably 21CN ADSL2+ since US isn't 448.)
thejudge
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Re: What Just Happened There?

I've just had to reboot the router because the SNR went negative (as I knew it would eventually with a synch speed over 6M), and it has now re-synched at 4.9M with an SNR bouncing between 6dB & 9dB.