Participant

Re: Ongoing connectivity issues / T3 timeouts


@MsRaye wrote:

 

What you have is all out of spec

 


Ha. That's funny. The tech from yesterday said it "was still in spec" and that even if the signal "scrapes the noise floor" it should be fine.

Common sense tells me that "scraping the noise floor" isn't good at all. I don't care how much this guy thinks he knows. He was knowledgeable, sure, but even intelligent people can still be ignorant.

 

Here's hoping for better luck with the visit tomorrow morning...

Thanks again, MsRaye.

Expert

Re: Ongoing connectivity issues / T3 timeouts

If it was 64 qam, yes, it works down at a 28 dB s/n

 the problem is that it's Qam 256 and that needs better s/n, I know it's horrible on 30 dB s/n  and works fine at 35 dB s/n but that's with 4 channels in a row.... yours is skipping over 3 channels with bad s/n and probably messing up the ALC in the dsp. I don't like seeing 45 db up with +10 downstream, that shows a misaligned amplifier or one that's being driven whacky by ingress before it.

 

 I expect horrible mismatched levels in apartment buildings, they're awfull to get coax replaced.

 

 

 Next issue, do you guys have packrats there?

 Is any of yours underground?

Just saw a picture of underground cables they gnawed thru that were in a plastic conduit.

 

Expert

Re: Ongoing connectivity issues / T3 timeouts

Printout the page i did with the ch 1-3-5 and frequencies, and if you have an error log page that shows DS partial service and the one that showed unlocked upstream channels.

 

Be sure to tell the tech the ch's 1-3-5 are  on local tv transmitter frequencies 8 miles away that are getting into the street trunk lines and probably before the nearest upstream amp.  It has to be a loose, broken or corroded hardline connector

 Also question why you're seeing a +10 dBmv downstream level, only a 32-33 dB s/n and upstream is + 44-45 dBmv.... Tell him the splitter that the last tech installed to use as an attenuator made errors worst. And that it's worst in the morning than afternoon/ evening. ( might be temperature related..

 He needs to go a half mile closer to the head end and look at the s/n there.

 

 If  there's any question on where i'm coming from, I have an FCC commercial license and spent 30+ years in the communication industry and spent a lot of it tracing down RF interference issues...

 

 

 

 

 

Participant

Re: Ongoing connectivity issues / T3 timeouts

The cable here is above ground; runs with the telephone lines.

None of it is below ground.

Participant

Re: Ongoing connectivity issues / T3 timeouts

Good morning,

 

I have another update after the second tech visit (I was surprised to see him here 10 minutes earlier than scheduled Smiley Surprised).

 

1) Different tech

2) He said the terminated splitter needed to stay on because there was nothing in between the modem and the line to the house to bring down the signal. It's simply just too high.

3) The news he shared to me about the possibility of RF ingress said that "It could happen, but highly unlikely." The reason the modem chose other channels, and not the ones that match up with over-the-air channel frequencies is because it looks for, in layman's terms "the shortest line with least number of people".

4) However, when checking the signal from the line at the pole tap, what he did find were several of hundreds of errors on all of the frequencies which meant the guys in bucket trucks needed to look at the (I forget what abbreviation he used; AEC? AGC? AEG?) - basically, the box on another pole near my house. He said the very cold temperatures could indeed have a factor in the mess.

These hundreds/thousands of errors, he confirmed, is what was causing the numerous T3 timeouts, and the eventual T4 timeout if it happens enough.

 

So, basically put, it's something on the line before my house after all, not the modem. He noted that the reason why the other tech said I might have a bad modem was because he didn't check the line for errors, which makes sense, because without doing so, there's no way to know the real cause.

Different tech said he'd put it in a maintenance ticket today and the bucket truck guys would be out here today at earliest.

As for the SNR, he said 32-33 is still "ok", as long as it doesn't hit 30 (which it hasn't) then it should not cause any problems. The thousands of errors on the line is the main culprit behind the spotty connection.

 

 

I probably left some details out due to lack of sleep from last night, but overall, from what he explained, it gave me a clear view of the real problem. He knew what he was looking at and checked everything this time, so I'm confident the real problem will be addressed now.

 

Edit: Updated signals. My modem chose channels 3 and 5 with no problem. I also have all of my Upstream channels back.

 

Channel ID
Frequency525000000 Hz 519000000 Hz 531000000 Hz 537000000 Hz 
Signal to Noise Ratio33 dB 33 dB 33 dB 33 dB 
Downstream ModulationQAM256 QAM256 QAM256 QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
7 dBmV  7 dBmV  7 dBmV  7 dBmV  

 

UpstreamBonding Channel Value
Channel ID
Frequency24200000 Hz 19400000 Hz 30600000 Hz 37000000 Hz 
Ranging Service ID13312 13312 13312 13312 
Symbol Rate5.120 Msym/sec 2.560 Msym/sec 5.120 Msym/sec 2.560 Msym/sec 
Power Level45 dBmV 46 dBmV 45 dBmV 45 dBmV 
Upstream Modulation[3] QPSK
[3] 64QAM
 
[3] QPSK
[2] 16QAM
 
[3] QPSK
[3] 64QAM
 
[3] QPSK
[2] 16QAM
 
Ranging StatusSuccess Success Success Success 

 

Signal Stats (Codewords)Bonding Channel Value
Channel ID
Total Unerrored Codewords111737118 110181589 110186988 110115754 
Total Correctable Codewords627521 639896 633666 706818 
Total Uncorrectable Codewords11380 10353 11321 13519 
Expert

Re: Ongoing connectivity issues / T3 timeouts

I love pulling teeth....

 30 will only work if it's only a single channel docsis 2 modem . For TWC's  Docsis 3   16 ch systems and older 4 channel modems that bumps the required s/n up a couple dB.

 And while it still "works" there's a lot more errors, which slow you and everyone else on the node down. errorsa and t3-4 timeouts just screw up everyone else on the node and slows it down, causes packet collisions etc.

 

I don't know if your system uses a pilot AGC or thermal AGC, that will upset levels, not create noise directly, Temperature problems mess with the fiber to coax conversion a lot more,

 It's a job for the bucket truck guys to find and fix

not the in house ones.

 

 

 as for skipped channels, well he's half correct, that's how channels work on a properly performing system.

Since your system isn't and there's noise/ ingress, and you see DS partial service, the bad channels are getting tossed out by the modem- cmts server.

All modems work better with their channels next to one another, some will only allow a 36 mhz max spacing

 

 

 

Expert

Re: Ongoing connectivity issues / T3 timeouts

Reset the FEC counters or the modem to 0 out the corected/ uncorrecteds, see if any channels have high counts after 12-24 hours operation.

 omething the tech took apart may have fixed the ingress for now., But again, it can be down the street somewwhere.

 

Participant

Re: Ongoing connectivity issues / T3 timeouts

It didn't occur to me to do another power reset until a few hours after the tech left (sleep deprivation is wonderful), which was at ~4:40pm local time.

It hasn't even been 6 hours since I did that, so I'll leave it overnight and post the signal and log in the morning.

 

Have a good night MsRaye.

 

- sm-tx

Participant

Re: Ongoing connectivity issues / T3 timeouts

Well... It was fine last night. The Unerrored codewords were only in the triple digits before I'd went to bed.

It's definitely the line, though, because it went out last night and the log is so cluttered with T3 errors that I can't even tell exactly when the connection died. It doesn't look like the modem rebooted, because I still have the same channels - and I lost one of my upstream channels.

 

Looks like I'm definitely stuck until they roll the bucket truck (which probably won't be until Monday)...

 

Signal after ~24hrs:

Channel ID
Frequency525000000 Hz 531000000 Hz 537000000 Hz 549000000 Hz 
Signal to Noise Ratio36 dB 36 dB 36 dB 36 dB 
Downstream ModulationQAM256 QAM256 QAM256 QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
4 dBmV  4 dBmV  4 dBmV  4 dBmV  

 

UpstreamBonding Channel Value
Channel ID
Frequency24200000 Hz 19400000 Hz 30600000 Hz 37000000 Hz 
Ranging Service ID8469 8469 8469 8469 
Symbol Rate5.120 Msym/sec 2.560 Msym/sec 5.120 Msym/sec 2.560 Msym/sec 
Power Level46 dBmV 47 dBmV 45 dBmV 46 dBmV 
Upstream Modulation[3] QPSK
[3] 64QAM
 
[3] QPSK
[2] 16QAM
 
[3] QPSK
[3] 64QAM
 
[3] QPSK
[2] 16QAM
 
Ranging StatusSuccess Success Retries Exceed Success 

 

Signal Stats (Codewords)Bonding Channel Value
Channel ID
Total Unerrored Codewords1761649529 1746256923 1708345262 1601031009 
Total Correctable Codewords373499515 387199135 419789552 502668036 
Total Uncorrectable Codewords12315370 14008337 19329581 43710758

 

Log:

Jan 23 2016 16:26:023-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:22:023-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:22:023-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:21:383-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:15:373-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:15:373-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:15:133-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:09:133-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:09:133-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:08:493-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:02:483-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:02:483-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 16:02:243-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:56:233-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:56:233-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:55:593-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:49:593-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:49:593-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:49:353-CriticalR05.0Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;
Jan 23 2016 15:43:343-CriticalR06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=30:60:23:d4:07:d2;CMTS-MAC=00:01:5c:48:ba:44;CM-QOS=1.1;CM-VER=3.0;

Expert

Re: Ongoing connectivity issues / T3 timeouts

Something got worst...

This has to be a broken line before an amp

and everything from that point to you is degraded.