50M : Post RS Errors

[Sephiroth]

The PT is fully competent at judging (and doing) what needs to be done including everything on your list.

Quite simply, Post-RS errors are bad - they should not occur. One can't rule out a dudgy Superhub and it'll prolly be the first thing the PT may try.

[Jon22]

PT has been, really pleasant bloke. He's swapped out the Superhub for another. Did also say that it could be that the coax cable is damaged but he didn't check it. I'll have to see if I get anymore errors, hopefully not.

[Jon22]

Still getting these errors despite the new Shub. Latest response via PM seems to suggest that as long as the connection stays up, then everything is fine.

Hey Jon,

Please to hear they're not service affecting. To be honest, it's not uncommon to see a few post and pre RS errors, if it's not directly service affecting then I wouldn't be overly concerned about it. In the early hours we tend to do any maintenance that's needed, so it's you may notice some service disturbances in the small hours.

Keep an eye and if you notice that your connection starts to play up then let me know.

Downstream
DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 299000000 267000000 275000000 283000000 291000000 307000000 315000000 323000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 13 9 10 11 12 14 15 16
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) 1.87 1.69 1.77 1.83 1.67 2.19 2.40 2.52
RxMER (dB) 36.61 36.61 36.39 36.61 36.84 36.84 36.84 36.84
Pre RS Errors 63628 27770 57325 20737 56711 63468 64958 69245
Post RS Errors 35396 10986 29775 10011 34528 42150 43650 47964

Upstream
US-1 US-2 US-3 US-4
Channel Type 2.0 N/A N/A 2.0
Channel ID 50 N/A N/A 51
Frequency (Hz) 39400000 N/A N/A 32600000
Ranging Status Success Other Other Success
Modulation 16QAM N/A N/A 16QAM
Symbol Rate (Sym/sec) 5120000 N/A N/A 5120000
Mini-Slot Size 4 N/A N/A 4
Power Level (dBmV) 47.25 N/A N/A 47.25
T1 Timeouts 0 0 0 0
T2 Timeouts 0 0 0 0
T3 Timeouts 2 0 0 1
T4 Timeouts 0 0 0 0

Most of those seem to of racked up overnight. I'm quite tempted to go down the CEO route even though I shouldn't really need to.

[Sephiroth]

There should be NO post-RS errors during normal operation. At your RxMER (SNR) level, I'd expect correctable errors. There should be NO uncorrectable errors and it is service affecting even if you hardly notice it.

Thing to find out is if your neighbours have the same.

VM's job is to get the noise out of the segment and I wouldn't find their answer satisfactory. It's a fob-off.

[Jon22]

Originally Posted by Sephiroth

There should be NO post-RS errors during normal operation. At your RxMER (SNR) level, I'd expect correctable errors. There should be NO uncorrectable errors and it is service affecting even if you hardly notice it.

Thing to find out is if your neighbours have the same.

VM's job is to get the noise out of the segment and I wouldn't find their answer satisfactory. It's a fob-off.

Yep, definitely seems like a fob off. Latest response just seems to have defaulted to the "Your connection works, what do you expect us to do?" answer. Hence, why I'm reluctantly thinking of going down the CEO route. Unless there's anything/anyone I can contact in between?

[Sephiroth]

I'll tell you where it's service affecting.

I you do any UDP downloads (you can Google UDP if necessary), there is no retransmission of corrupted packets unless your end (application has software to detect this. When you try to unpack such downloads, a CRC error occurs and the data is useless.

Zero post-RS (except for the boot up moments) is the only acceptable level.

[Jon22]

To be honest, I don't know if I do do any UDP downloads. Googled it, still not sure.

[qasdfdsaq]

Originally Posted by Sephiroth

There should be NO post-RS errors during normal operation. At your RxMER (SNR) level, I'd expect correctable errors. There should be NO uncorrectable errors and it is service affecting even if you hardly notice it.

I would disagree. Consumer products are neither designed nor expected to be 100% reliable. You could say there should be NO dropped calls or cut-outs during normal operation of a mobile network but nobody returns a phone because it drops one or two calls every year.

---------- Post added at 11:19 ---------- Previous post was at 11:18 ----------

Originally Posted by Jon22

To be honest, I don't know if I do do any UDP downloads. Googled it, still not sure.

You don't. Nobody does. UDP is not used for downloading.*

* It's sometimes used for torrents but that has it's own error checking and retransmission anyway.

---------- Post added at 11:20 ---------- Previous post was at 11:19 ----------

Originally Posted by Sephiroth

Zero post-RS (except for the boot up moments) is the only acceptable level.

I challenge you to find *any* internet service in the world that has zero packet loss at any time.

[jb66]

I can't see the point in all of this. It works. If I had 10 billion errors I couldn't care as long as my service works

[Kushan]

Originally Posted by qasdfdsaq

You don't. Nobody does. UDP is not used for downloading.*

Downlads no, but I'd be interested in knowing how real time services like VoIP and Gaming are. Those are where you're going to see major issues.

Completely agree with everything else though - nothing is ever guaranteed to be 100% reliable, TCP itself was built around the principle that it's not reliable.

[sollp]

Originally Posted by Sephiroth

I'll tell you where it's service affecting.

I you do any UDP downloads (you can Google UDP if necessary), there is no retransmission of corrupted packets unless your end (application has software to detect this. When you try to unpack such downloads, a CRC error occurs and the data is useless.

Zero post-RS (except for the boot up moments) is the only acceptable level.

Agree that there should be no post errors, if you have post errors the Forward Errors Control,(FEC) cannot correct the errors and depending on how bad it is will determine as to what level of disruption will occur to your picture or Broadband service.

I also agree that most networks will have a small amount of errors but VM do have a spec at the cab that shouldn't be exceeded

[Jon22]

Would this affect streaming from Netflix? I usually get the picture going pixelated once or twice for a few seconds, regardless of what I'm watching. I assumed it was something to do with Netflix but perhaps not.

I also notice that I'm getting a few T3 timeouts recently and that the upstream power is slowly climbing up.

[Kushan]

For UDP, you'll get missing packets so anything "Realtime" will go missing.

For TCP (which I think is what Netflix will use?), you'll see lower speeds as TCP retransmits until it goes through. For netflix, that could cause a drop in picture quality as netflix is fairly dynamic.

[Jon22]

Originally Posted by Kushan

For UDP, you'll get missing packets so anything "Realtime" will go missing.

For TCP (which I think is what Netflix will use?), you'll see lower speeds as TCP retransmits until it goes through. For netflix, that could cause a drop in picture quality as netflix is fairly dynamic.

I have noticed that too, although it doesn't happen too often. Sometimes it'll just drop the quality down to 240 and then reasonably quickly, work its way back up to 1080.

[qasdfdsaq]

Originally Posted by Jon22

I have noticed that too, although it doesn't happen too often. Sometimes it'll just drop the quality down to 240 and then reasonably quickly, work its way back up to 1080.

This can happen for hundreds of different reasons.

You need to stop speculating and post a TBB graph to determine if it's service affecting or not.