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LiberatedLampre's avatar
LiberatedLampre
New Contributor

Not using all Modem Channels & A *LOT* of channel uncorrectables for some channels.

Hoping a Cox community support agent can help here. For any non-Cox readers I have Ultimate service (but would possibly commit war crimes to get Gigablast).

I finally have the right service level after Cox kept provisioning me down because their records kept reporting me to have a cable modem that only had 8 downstream and 4 upstream channels. I'd call and say that I had a SB6190 with 32 downstream channels and 8 upstream channels...and I'd be told such a product didn't exist. I'd argue that all they had to do was google SB6190 and they'd see it widely available. Finally they'd relent and put that modem on my account. Two weeks would pass and I'd be re provisioned back down to 8x4. I finally got a nerdy sounding girl on the phone who believed me because it was doubtful an average person even knew what channels were and she said she'd opened up an "ancient POS system no one uses anymore" to fix my account.

I'm now able to get 24 channels down, and 4 up. 

So Question 1  - Is it possible to get 32 channels down and 8 channels up in my service area?

Next is the number of uncorrectables I have in my downstream. I've noticed massive swings in throughput of data - basically dropping from 10+ MB/s downsteam to maybe 100 KB/s downstream and vacillating back and forth. I'm wondering if the above Question 1 plays into this, but further wondering if the following channel information is dispositive on the issue.

Question 2 - Are these uncorrectable levels normal? In the event the below copy/paste does not display properly for the viewer please note that for each channel listed the 2nd to last number is the number of Correctables and the final number is the number of Uncorrectables. Channels 16-20 seem to be having the most problems.

Additional Pertinent Informaiton - My service is Internet & Phone only. The line enters the home, has one splitter (supplied by Cox during install), and then goes to the internet modem & the phone modem directly since I have everything centrally wired in my home. All coax sockets in the home are completely disconnected. All fittings were re-done by Cox during install. I've checked the connectors and all are firmly seated. No signal boosting equipment or any other equipment is on the Coax line to add noise.

Total Uptime For this Data is 3 Days, 6 hours, 20 minutes

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked 256QAM 80 855.00 MHz -4.80 dBmV 38.61 dB 957 2050
2 Locked 256QAM 73 813.00 MHz -5.40 dBmV 38.61 dB 3688 57
3 Locked 256QAM 74 819.00 MHz -4.90 dBmV 38.61 dB 2174 81
4 Locked 256QAM 75 825.00 MHz -4.80 dBmV 38.61 dB 1064 85
5 Locked 256QAM 76 831.00 MHz -4.80 dBmV 38.61 dB 849 104
6 Locked 256QAM 77 837.00 MHz -4.90 dBmV 38.61 dB 1400 1117
7 Locked 256QAM 78 843.00 MHz -5.30 dBmV 38.61 dB 1643 2143
8 Locked 256QAM 79 849.00 MHz -5.50 dBmV 38.98 dB 1911 1925
9 Locked 256QAM 81 861.00 MHz -4.80 dBmV 38.61 dB 1060 1892
10 Locked 256QAM 82 867.00 MHz -5.30 dBmV 37.64 dB 1305 1940
11 Locked 256QAM 83 873.00 MHz -5.70 dBmV 38.98 dB 1426 65
12 Locked 256QAM 84 879.00 MHz -5.90 dBmV 37.64 dB 1258 55
13 Locked 256QAM 85 885.00 MHz -5.70 dBmV 37.64 dB 613 54
14 Locked 256QAM 86 891.00 MHz -5.80 dBmV 37.64 dB 359 57
15 Locked 256QAM 87 897.00 MHz -5.90 dBmV 38.61 dB 345 76
16 Locked 256QAM 88 903.00 MHz -6.60 dBmV 38.61 dB 911876 6641760
17 Locked 256QAM 89 909.00 MHz -6.60 dBmV 37.64 dB 1463954 11047220
18 Locked 256QAM 90 915.00 MHz -6.10 dBmV 38.61 dB 1490111 11054861
19 Locked 256QAM 91 921.00 MHz -5.60 dBmV 38.61 dB 1342435 10162222
20 Locked 256QAM 92 927.00 MHz -5.00 dBmV 38.61 dB 806356 6009483
21 Locked 256QAM 93 933.00 MHz -5.10 dBmV 38.61 dB 489 1725
22 Locked 256QAM 94 939.00 MHz -4.80 dBmV 38.98 dB 552 1767
23 Locked 256QAM 95 945.00 MHz -4.30 dBmV 38.98 dB 84 86
24 Locked 256QAM 96 951.00 MHz -3.80 dBmV 38.61 dB 70 33

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  • grymwulf's avatar
    grymwulf
    Contributor II

    First off, many markets only have 24 channels, so you need to wait for infrastructure upgrades before all 32 channels will be available.  Secondly, be glad you don't have all 32 channels, the SB6190 is several firmware revisions before being stable - the PUMA 6 chipset from Intel is doing software routing versus hardware accelerated.  At least that is what analysis looks like:

    http://www.dslreports.com/forum/r31079834-ALL-SB6190-is-a-terrible-modem-Intel-Puma-6-MaxLinear-mistake

    However, it is also reported that ICMPv4/IPv4 traffic with the most recent firmware has been changed to process through hardware acceleration - so your mileage may vary, depending on which version of the firmware has been rolled out.

    As to your other question - your error rate should be less than .01% (ideally less than 1e-06) - you do appear to have some issues on channels 16-20, I'd reset your modem and let it run for a couple of days and see if the problem persists.  Pick up a SB6183 and swap modems, run it for a couple of days to see if it has the same issue.

  • LiberatedLampre's avatar
    LiberatedLampre
    New Contributor

    I've reset the modem & had it reprovisioned more times than I can count at this point. Each time I call Cox about it I get a different answer.

    1. That I'm not supposed to access the modem and view that information

    2. That errors are normal and not to worry about it.

    3. That they can only send a tech out, but if it turns out to be the modem then I'll pay $100 for a service call.

    So before I either get an RMA on the modem or pay $100 for a service call I wanted to see if there was something more to be gleaned. I'm really hoping to just be able to ride out the SB6190 till the DOCSIS 3.1 modems are out.

  • grymwulf's avatar
    grymwulf
    Contributor II

    As far as I know, service calls should be around $75 - and that should (note the should) only be charged if the problem is inside the demarcation point (IE where the wire enters the building) *and* not caused by equipment that Cox has provided.

    For #1 - I doubt any of the tier 1 people at cox can understand the majority of that diagnostic info (heck they may not have access to it either!)

    #2 If you are getting error rates over 0.01% there definitely is a problem, talk to someone in tier 2

    #3 - if it isn't caused by something that they can address remotely or over the phone, a service technician is the only one that can help at that point.

    Recommendation: pick up a SB6183 try it for a couple of days, if the problem is resolved you *know* it was the modem.  Or heck stop in to a retail location and pick up their ultimate gateway (Arris TG2472?) and rent that for a couple of days, see if it helps.  They can't claim it was your modem if their modem is doing the exact same thing.

  • LiberatedLampre's avatar
    LiberatedLampre
    New Contributor

    I called Arris (modem manufacturer) to see what they said, and they're telling me the signal levels are out of spec. They're saying the modem will only work right within +/- 5 dBmV, and that once you get close to +/- 7 dBmV that the modem will start having issues. Arris did recommend hard resetting the modem's configuration - there's a pinhole on the back of the modem to let the owner do that - but it's not made any discernable difference.

    My question is - Is there any way for me to know that Cox will send someone out who specifically will make sure my signal levels are within +/- 5 dBmV? Every past tech sent out told me they only had to make sure it was within +/- 10 dBmV. Arris claims there's nothing they can do unless Cox gets the signal levels right. I don't want to pay for a service call simply because Arris has higher standards than Cox.

    Here is my current status after 2 hours of uptime.

    Downstream Bonded Channels
    Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
    1 Locked 256QAM 94 939.00 MHz -6.40 dBmV 37.64 dB 20 0
    2 Locked 256QAM 73 813.00 MHz -6.00 dBmV 38.61 dB 29 0
    3 Locked 256QAM 74 819.00 MHz -5.30 dBmV 38.61 dB 5 0
    4 Locked 256QAM 75 825.00 MHz -5.10 dBmV 38.98 dB 4 0
    5 Locked 256QAM 76 831.00 MHz -4.90 dBmV 38.61 dB 1 0
    6 Locked 256QAM 77 837.00 MHz -5.10 dBmV 38.98 dB 5 0
    7 Locked 256QAM 78 843.00 MHz -5.50 dBmV 38.61 dB 7 0
    8 Locked 256QAM 79 849.00 MHz -6.00 dBmV 38.61 dB 8 0
    9 Locked 256QAM 80 855.00 MHz -5.70 dBmV 38.61 dB 2 0
    10 Locked 256QAM 81 861.00 MHz -5.90 dBmV 38.98 dB 2 0
    11 Locked 256QAM 82 867.00 MHz -6.60 dBmV 37.64 dB 4 0
    12 Locked 256QAM 83 873.00 MHz -7.00 dBmV 37.64 dB 4 0
    13 Locked 256QAM 84 879.00 MHz -6.80 dBmV 37.64 dB 7 0
    14 Locked 256QAM 85 885.00 MHz -6.40 dBmV 38.26 dB 6 0
    15 Locked 256QAM 86 891.00 MHz -6.10 dBmV 37.64 dB 19 0
    16 Locked 256QAM 87 897.00 MHz -5.90 dBmV 38.61 dB 0 0
    17 Locked 256QAM 88 903.00 MHz -6.70 dBmV 37.64 dB 21718 165103
    18 Locked 256QAM 89 909.00 MHz -6.70 dBmV 37.64 dB 34822 270206
    19 Locked 256QAM 90 915.00 MHz -6.40 dBmV 38.61 dB 33179 240578
    20 Locked 256QAM 91 921.00 MHz -6.30 dBmV 38.98 dB 33939 259481
    21 Locked 256QAM 92 927.00 MHz -5.90 dBmV 37.64 dB 20965 161370
    22 Locked 256QAM 93 933.00 MHz -6.20 dBmV 37.64 dB 0 0
    23 Locked 256QAM 95 945.00 MHz -6.00 dBmV 38.61 dB 0 0
    24 Locked 256QAM 96 951.00 MHz -5.40 dBmV 38.98 dB 0 0
  • grymwulf's avatar
    grymwulf
    Contributor II

    Actually the spec is +/- 15 not 5, Cox actually tries to get it in +/- 10.  If Arris is saying that their modems are not following the DOCSIS spec that would be posted all over the place.  Here's a summary of signal levels according to the DOCSIS 3.0 specifications: http://www.dslreports.com/faq/3692

    So #1 whomever you talked to at Arris either didn't know what they were talking about, or didn't understand things.

    Again, you are having issues with those channels, and if you have ruled out the modem being an issue, it would appear to be a physical layer problem which only a tech can address.

  • cpljp's avatar
    cpljp
    Contributor

    Arris support seems to have this clueless claim they tell everyone that power levels need to be between -5 dbmv and +5dbmv which is a load of bologna. 

    You seem to have noise from the ISM band, which is likely causing issues and you may very well have noise on the return band and other frequencies as well.

    I'd recommend a service call

  • LiberatedLampre's avatar
    LiberatedLampre
    New Contributor

    Line tech came out today. He didn't really know much about what I was talking about with uncorrectable errors, but he was happy to check the line coming in and see if anything obvious was going on. The drop to the house was due for replacement as they don't even have a record of how old it is, but he would have to schedule that part. At the drop box he removed an old data trap that was no longer being used. Then further down the line he changed out my 3-way splitter to a 2-way. This pretty much gave me signal levels at +/- 2 dBmV with most hovering right around 0 - so the signal level is perfect.

    But the errors got worse afterwards. The line tech said the very likely culprit is the SB6190 modem I have. 

    The current status after 5 hours of uptime are listed below.

    What does everyone think I should do?

    Downstream Bonded Channels
    Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
    1 Locked 256QAM 94 939.00 MHz 0.20 dBmV 38.98 dB 130 63
    2 Locked 256QAM 73 813.00 MHz -1.10 dBmV 38.61 dB 659 1197
    3 Locked 256QAM 74 819.00 MHz -0.30 dBmV 38.98 dB 485 1175
    4 Locked 256QAM 75 825.00 MHz 0.20 dBmV 38.61 dB 839 4075
    5 Locked 256QAM 76 831.00 MHz 0.40 dBmV 38.98 dB 532 3206
    6 Locked 256QAM 77 837.00 MHz 0.50 dBmV 38.61 dB 448 2301
    7 Locked 256QAM 78 843.00 MHz 0.50 dBmV 38.98 dB 367 134
    8 Locked 256QAM 79 849.00 MHz 0.40 dBmV 38.61 dB 266 132
    9 Locked 256QAM 80 855.00 MHz 0.80 dBmV 38.98 dB 284 1023
    10 Locked 256QAM 81 861.00 MHz 0.60 dBmV 38.98 dB 290 1031
    11 Locked 256QAM 82 867.00 MHz 0.20 dBmV 38.98 dB 167 85
    12 Locked 256QAM 83 873.00 MHz -0.30 dBmV 38.61 dB 197 0
    13 Locked 256QAM 84 879.00 MHz -0.60 dBmV 38.61 dB 199 0
    14 Locked 256QAM 85 885.00 MHz 0.00 dBmV 38.61 dB 84 0
    15 Locked 256QAM 86 891.00 MHz 0.20 dBmV 38.61 dB 231 1218
    16 Locked 256QAM 87 897.00 MHz 0.00 dBmV 38.61 dB 311 2170
    17 Locked 256QAM 88 903.00 MHz -0.40 dBmV 38.61 dB 23839 124597
    18 Locked 256QAM 89 909.00 MHz -0.20 dBmV 38.61 dB 71921 514423
    19 Locked 256QAM 90 915.00 MHz 0.00 dBmV 38.61 dB 70530 492331
    20 Locked 256QAM 91 921.00 MHz 0.20 dBmV 38.98 dB 69272 500817
    21 Locked 256QAM 92 927.00 MHz 0.50 dBmV 38.98 dB 40019 265099
    22 Locked 256QAM 93 933.00 MHz 0.20 dBmV 38.61 dB 171 1021
    23 Locked 256QAM 95 945.00 MHz 0.60 dBmV 38.61 dB 38 31
    24 Locked 256QAM 96 951.00 MHz 1.40 dBmV 38.98 dB 0 0
  • LiberatedLampre's avatar
    LiberatedLampre
    New Contributor

    I should also add that the line tech said the T3 and T4 error counts were *way* too high after just a couple of minutes of the modem being on. Arris told me that even if the modem is replaced those T3 and T4 errors means Cox needs to fix problems at the Node or further back or else my connection will still have problems.

    Is there some magic words I need to use to get Cox to fix those problems?

  • LiberatedLampre's avatar
    LiberatedLampre
    New Contributor

    So new SB6190, and after 6 days of uptime I am right back where I am on errors. Cox is saying they'll send another tech out, but won't promise they'll actually do anything since the signal level seem fine.

    Downstream Bonded Channels
    Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
    1 Locked 256QAM 94 939.00 MHz 1.60 dBmV 38.98 dB 24968 128691
    2 Locked 256QAM 73 813.00 MHz 0.90 dBmV 38.98 dB 21443 86099
    3 Locked 256QAM 74 819.00 MHz 1.60 dBmV 38.98 dB 19672 71148
    4 Locked 256QAM 75 825.00 MHz 2.00 dBmV 38.61 dB 21409 79950
    5 Locked 256QAM 76 831.00 MHz 2.10 dBmV 38.98 dB 21529 73651
    6 Locked 256QAM 77 837.00 MHz 1.90 dBmV 38.61 dB 24612 91195
    7 Locked 256QAM 78 843.00 MHz 2.20 dBmV 38.98 dB 24294 99773
    8 Locked 256QAM 79 849.00 MHz 2.20 dBmV 38.61 dB 24873 106190
    9 Locked 256QAM 80 855.00 MHz 2.70 dBmV 40.37 dB 29467 132605
    10 Locked 256QAM 81 861.00 MHz 2.70 dBmV 38.98 dB 26417 123508
    11 Locked 256QAM 82 867.00 MHz 2.30 dBmV 38.61 dB 26093 125984
    12 Locked 256QAM 83 873.00 MHz 1.80 dBmV 38.98 dB 23562 120314
    13 Locked 256QAM 84 879.00 MHz 1.60 dBmV 38.61 dB 20960 104568
    14 Locked 256QAM 85 885.00 MHz 2.10 dBmV 38.98 dB 17819 74305
    15 Locked 256QAM 86 891.00 MHz 2.10 dBmV 38.98 dB 20633 77506
    16 Locked 256QAM 87 897.00 MHz 1.90 dBmV 38.98 dB 20082 75504
    17 Locked 256QAM 88 903.00 MHz 1.10 dBmV 38.98 dB 455873 2308291
    18 Locked 256QAM 89 909.00 MHz 1.20 dBmV 38.61 dB 1399522 9274155
    19 Locked 256QAM 90 915.00 MHz 1.20 dBmV 40.37 dB 1640914 11386982
    20 Locked 256QAM 91 921.00 MHz 1.40 dBmV 38.98 dB 1930996 13509996
    21 Locked 256QAM 92 927.00 MHz 1.80 dBmV 38.98 dB 1096600 7529472
    22 Locked 256QAM 93 933.00 MHz 1.60 dBmV 38.61 dB 27944 132417
    23 Locked 256QAM 95 945.00 MHz 2.00 dBmV 38.61 dB 24671 116279
    24 Locked 256QAM 96 951.00 MHz 2.60 dBmV 40.37 dB 20379 94354

     

  • grymwulf's avatar
    grymwulf
    Contributor II

    This does look like a Layer 1 issue - physical noise/interference on the actual physical connection  As such, only a visit by a technician and determination of where the problem is.  

    TL;DR - there is a physical problem somewhere with the connection: Modem -> Coax -> Node