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Sudden explosion in post RS errors

All of a sudden, seem to be getting a mountain of post RS errors on my connection, having never had a problem with them before. As an example, I reset the counts last night following turning the router on and off. Have woke up this morning and already the counts are as shown below:

DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 250750000 234750000 242750000 258750000 266750000 274750000 282750000 290750000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 43 41 42 44 61 62 63 64
Modulation 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) 1.23 1.57 1.57 1.14 1.10 0.73 0.41 0.25
RxMER (dB) 39.40 39.40 39.40 38.61 39.85 39.40 39.85 39.40
Pre RS Errors Reset Counter 1649 1761 1578 1412 1216 1114 1033 940
Post RS Errors Reset Counter 393 406 392 306 214 149 94 104

More curiously, theres nothing new in the network log - I cleared that at the same time, and its still empty this morning.
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Re: Sudden explosion in post RS errors

The post RS errors are normal, as it is usual to acquire a few hundred post RS errors on boot up as the hub has to sift through a fair bit of rubbish before it can hunt down a downstream channel to lock on to.

The number of errors is not important, but the rate of increase of the errors is. A rapid increase in errors, say hundreds per minute would indicate a downstream problem You would also expect to see other evidence of a downstream problem in the logs and in the hub's stats.

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Re: Sudden explosion in post RS errors

Understood, though I did clear the error counts after the reboot - so it had already locked onto the channels at that point. The figures shown there came during the nine or ten hours once the reboot process was complete.

Will take another look at the figures when I'm home from work and see if there's been any changes...

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Re: Sudden explosion in post RS errors

After a couple of days of there being no change, there's been another run of them today while I was at work, it appears:

DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 250750000 234750000 242750000 258750000 266750000 274750000 282750000 290750000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 43 41 42 44 61 62 63 64
Modulation 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM 256QAM
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) 0.59 0.98 1.10 0.45 0.38 0.14 -0.07 -0.05
RxMER (dB) 38.98 38.98 39.40 38.61 39.40 39.40 39.40 39.40
Pre RS Errors Reset Counter 3124 2842 2165 1892 1625 1480 1402 1273
Post RS Errors Reset Counter 449 482 503 397 255 178 121 147

Still nothing showing in the network log as an incident however. Looks like it might be happening in short spells...?
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Re: Sudden explosion in post RS errors

Every network on the planet has errors, they are unavoidable. Cablelabs Docsis specification specifies a max error rate of 9*10^-7, or 90 bits per second on a 100Mbps connection. (See p96 of spec to see how this is dervied). 90 bad bits in a hundred million bits is not bad.

Depending on your usage, a few thousand pre RS errors and a couple of hubdred post RS errors should not affect performance at all. Brady Volpe provides a more practical insight here and a description here. . This is also a good read.

Noise bursts can cause Errors, but I would expect the logs to show some errors if this was happening and would expect a higher error count.

Are you having problems with your connection?

If so, please post further details so we can help.

 

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Re: Sudden explosion in post RS errors

Reset the counters to zero about three and a half hours ago.. and having checked them just now..

Pre RS Errors Reset Counter 485 663 516 495 441 429 387 364
Post RS Errors Reset Counter 22 116 75 72 42 20 12 11

Still nothing in the network log. Connection has been occasionally temperamental in the last few weeks with speeds more erratic than usual, but no noticed issues connecting and no disconnects.

Just seems odd / worrying theres been pretty much none for years, and now it's a fairly regular occurrence..
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Re: Sudden explosion in post RS errors

Are you connecting wired or wirelessly when experiencing the tempermental connection?

 

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Re: Sudden explosion in post RS errors

Wirelessly. Due to the location of the router, there's not much able to be connected via wired!
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Re: Sudden explosion in post RS errors

Once again reset the counters at about half 11 last night, and eight hours later..

Pre RS Errors Reset Counter 1277 1688 1428 1356 1332 1184 1132 1029
Post RS Errors Reset Counter 130 480 440 333 336 243 167 111

As it was overnight, myself and my wife haven't even actively been using the connection in that period.

Is anyone from Virgin able to look into this, as having had no errors for so long, getting this number of errors in such a short space of time (repeatedly) is somewhat worrying..?
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Re: Sudden explosion in post RS errors

After being advised there was a 'SNR issue with one channel' (?) on the phone on Saturday, and that it'd be 'fixed within 48hrs', things were suddenly fine with no post RS errors at all since Sunday last weekend.. until today, when it's back to errors again as of a few hours ago.

Very frustrating. As is the lack of reply from Virgin on here at any point, and the very vague response provided on the phone (including vague resolution time).
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