Forum Discussion

shipracer's avatar
shipracer
New Contributor III
4 years ago

Upstream packet loss and jitter

Hey Guys, Non-stop packetloss all day. Cox is saying everything is okay, I have been graphing/monitoring the loss for months. What resolutions do we have besides switching ISPs? Are there any ...
Dave9's avatar
Dave9
Contributor III

Are you seeing any T3 or T4 timeout errors in your modem logs? Remember that you need to let the modem run for at least 24 hours without restarting it for this to be a valid test. Same goes for signal levels. If you post signals right after restarting the modem it makes the values look artificially good.

shipracer's avatar
shipracer
New Contributor III
4 years ago

I did not know that. Here are the EVENTS from the modem.

Time Priority Description
Sat Jul 03 22:06:41 2021 3 No Ranging Response received - T3 time-out;CM-MAC=d4:04:cd:24:d5:f9;CMTS-MAC=84:8a:8d:33:77:23;CM-QOS=1.1;CM-VER=3.0;
Mon Jul 05 03:10:03 2021 5 RCS Partial Service;CM-MAC=d4:04:cd:24:d5:f9;CMTS-MAC=84:8a:8d:33:77:23;CM-QOS=1.1;CM-VER=3.0;
Mon Jul 05 09:50:56 2021 3 No Ranging Response received - T3 time-out;CM-MAC=d4:04:cd:24:d5:f9;CMTS-MAC=84:8a:8d:33:77:23;CM-QOS=1.1;CM-VER=3.0;

Here are the signals:

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK
Security Enabled BPI+
DOCSIS Network Access Enabled Allowed

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked 256QAM 29 951.00 MHz 8.10 dBmV 40.95 dB 12819 1352
2 Locked 256QAM 1 783.00 MHz 8.80 dBmV 43.38 dB 26956 7046
3 Locked 256QAM 2 789.00 MHz 8.60 dBmV 40.95 dB 25280 5523
4 Locked 256QAM 3 795.00 MHz 8.50 dBmV 43.38 dB 21831 3302
5 Locked 256QAM 4 801.00 MHz 8.50 dBmV 40.95 dB 23300 3851
6 Locked 256QAM 5 807.00 MHz 8.50 dBmV 40.95 dB 24348 3556
7 Locked 256QAM 6 813.00 MHz 8.40 dBmV 43.38 dB 20451 2017
8 Locked 256QAM 7 819.00 MHz 8.30 dBmV 40.95 dB 21948 2482
9 Locked 256QAM 8 825.00 MHz 8.20 dBmV 40.95 dB 23707 3352
10 Locked 256QAM 9 831.00 MHz 8.00 dBmV 40.95 dB 24708 5228
11 Locked 256QAM 10 837.00 MHz 7.90 dBmV 40.95 dB 25357 9086
12 Locked 256QAM 11 843.00 MHz 7.80 dBmV 40.95 dB 22830 4559
13 Locked 256QAM 12 849.00 MHz 8.00 dBmV 40.95 dB 23915 8329
14 Locked 256QAM 13 855.00 MHz 8.00 dBmV 40.95 dB 22229 6904
15 Locked 256QAM 14 861.00 MHz 8.10 dBmV 40.95 dB 19973 2547
16 Locked 256QAM 15 867.00 MHz 8.10 dBmV 40.37 dB 18073 2125
17 Locked 256QAM 16 873.00 MHz 8.10 dBmV 40.95 dB 18765 3912
18 Locked 256QAM 17 879.00 MHz 8.00 dBmV 40.95 dB 16767 1555
19 Locked 256QAM 18 885.00 MHz 8.00 dBmV 40.95 dB 20869 3613
20 Locked 256QAM 19 891.00 MHz 7.90 dBmV 40.95 dB 27591 7020
21 Locked 256QAM 20 897.00 MHz 7.90 dBmV 40.37 dB 24523 10712
22 Locked 256QAM 21 903.00 MHz 7.80 dBmV 40.95 dB 24621 24422
23 Locked 256QAM 22 909.00 MHz 7.80 dBmV 40.95 dB 24325 20907
24 Locked 256QAM 23 915.00 MHz 7.70 dBmV 40.95 dB 23351 26972
25 Locked 256QAM 24 921.00 MHz 7.90 dBmV 41.90 dB 3583 2203
26 Locked 256QAM 25 927.00 MHz 8.10 dBmV 41.90 dB 2492 2662
27 Locked 256QAM 26 933.00 MHz 8.10 dBmV 41.10 dB 2412 2087
28 Locked 256QAM 27 939.00 MHz 8.30 dBmV 40.40 dB 4670 2299
29 Locked 256QAM 28 945.00 MHz 8.30 dBmV 41.90 dB 4841 2459
30 Locked 256QAM 30 957.00 MHz 8.10 dBmV 40.40 dB 10671 2673
31 Locked 256QAM 31 963.00 MHz 7.90 dBmV 41.10 dB 9694 1731
32 Locked 256QAM 32 969.00 MHz 7.70 dBmV 41.10 dB 10160 1905

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 3 5120 kSym/s 30.40 MHz 42.25 dBmV
2 Locked ATDMA 4 5120 kSym/s 36.80 MHz 42.25 dBmV
3 Locked ATDMA 2 5120 kSym/s 24.00 MHz 42.25 dBmV
4 Locked ATDMA 1 5120 kSym/s 17.60 MHz 42.00 dBmV
  • Dave9's avatar
    Dave9
    Contributor III
    4 years ago

    Do you normally see uncorrectable counts that high? The only time it's normal to see that level of uncorrectables is after maintenance was done on the line or on the node. Try resetting the modem and see if the uncorrectable count continues to increase. If it does, that's not normal. I think it might be due to maintenance due to the partial service event in your logs from 3 AM.

    For comparison, outside of maintenance times, I get a total of about 10 uncorrectables per year (my downstream connection is basically flawless). So it is definitely not normal to see over 75,000 during the course of a day.

    Having 2 T3 timeouts in 2 days isn't ideal but it's not frequent enough to definitely point to an upstream noise issue. You'll need to keep gathering information until a pattern becomes evident.

    • shipracer's avatar
      shipracer
      New Contributor III
      4 years ago

      That seems abnormal. I do see some uncorrectables normally. but on a single channel or 2. I will reset and continue to monitor/gather information.

      • Dave9's avatar
        Dave9
        Contributor III
        4 years ago
        I do see some uncorrectables normally. but on a single channel or 2.

        That means noise is leaking into the line on those frequencies. Might be "acceptable" under Cox minimum standards, but it's not normal.