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steve-o's avatar
steve-o
Tuning in
5 hours ago

T3 timeouts & dropping connections

As title. Hub 5, in modem mode.

Physical connections checked then rebooted at 19:24 this evening to see whether timeouts issues persist - looks like yes. I think the timeouts explain the dropped connections. It's been like this for a couple of weeks now.

There were lots of downstream post-RS errors prior to reboot, but it's not been rebooted for a while.

 

3.0 Upstream channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

0 49600000 48.5 5120 QAM 64 1

1 43100000 48.5 5120 QAM 64 2

2 36600000 48.5 5120 QAM 64 3

3 30100000 48.5 5120 QAM 64 4

4 23600000 48.8 5120 QAM 64 9

 

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

0 ATDMA 0 0 0 0

1 ATDMA 0 0 0 0

2 ATDMA 0 0 9 0

3 ATDMA 0 0 0 0

4 ATDMA 0 0 0 0

 

 

3.1 Upstream channels

Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation

10 10.4 43.7 2K QAM 256

 

3.1 Upstream channels

Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts

10 OFDMA 208 74000000 0 0

 

3.0 Downstream channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1 139000000 6.2 39 QAM 256 1

2 147000000 6.6 39 QAM 256 2

3 155000000 6.6 39 QAM 256 3

4 163000000 6.8 40 QAM 256 4

5 171000000 6.9 40 QAM 256 5

6 179000000 7.1 40 QAM 256 6

7 187000000 7.2 40 QAM 256 7

8 195000000 7.8 41 QAM 256 8

9 203000000 8 41 QAM 256 9

10 211000000 8.1 41 QAM 256 10

11 219000000 8 41 QAM 256 11

12 227000000 8 41 QAM 256 12

13 235000000 8 41 QAM 256 13

14 243000000 8 41 QAM 256 14

15 251000000 7.7 41 QAM 256 15

16 259000000 7.5 40 QAM 256 16

17 267000000 7.5 40 QAM 256 17

18 275000000 7.8 41 QAM 256 18

19 283000000 8.9 41 QAM 256 19

20 291000000 9.8 41 QAM 256 20

21 299000000 10 41 QAM 256 21

22 307000000 10.2 41 QAM 256 22

23 315000000 10.3 41 QAM 256 23

24 323000000 10.4 41 QAM 256 24

25 331000000 10.3 41 QAM 256 25

26 411000000 9.9 41 QAM 256 35

27 419000000 9.7 41 QAM 256 36

28 427000000 9.8 41 QAM 256 37

29 435000000 10.3 41 QAM 256 38

30 443000000 10.7 41 QAM 256 39

31 451000000 10.9 41 QAM 256 40

 

3.0 Downstream channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1 Locked 39 0 0

2 Locked 39 0 0

3 Locked 39 0 0

4 Locked 40 0 0

5 Locked 40 0 0

6 Locked 40 0 0

7 Locked 40 0 0

8 Locked 41 0 0

9 Locked 41 0 0

10 Locked 41 0 0

11 Locked 41 0 0

12 Locked 41 0 0

13 Locked 41 0 0

14 Locked 41 0 0

15 Locked 41 1 0

16 Locked 40 0 0

17 Locked 40 0 0

18 Locked 41 0 0

19 Locked 41 0 0

20 Locked 41 0 0

21 Locked 41 0 0

22 Locked 41 0 0

23 Locked 41 0 0

24 Locked 41 0 0

25 Locked 41 0 0

26 Locked 41 0 0

27 Locked 41 0 0

28 Locked 41 0 0

29 Locked 41 0 0

30 Locked 41 0 0

31 Locked 41 0 0

 

3.1 Downstream channels

Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)

41 94 4K 1840 QAM 4096 1108

 

3.1 Downstream channels

Channel ID Locked Status RxMER Data (dB) PLC Power (dBmV) Corrected errors (Active Profile) Uncorrectable errors (Active Profile)

41 Locked 0 10.5 268124901 0

 

Network Log

Time Priority Description

22-01-2026 21:23:37 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 21:23:35 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 21:23:35 critical 16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 21:23:29 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 21:10:35 notice US profile assignment change. US Chan ID: 10; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 21:05:32 notice US profile assignment change. US Chan ID: 10; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 20:53:24 notice US profile assignment change. US Chan ID: 10; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 20:48:21 notice US profile assignment change. US Chan ID: 10; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:24:30 notice REGISTRATION COMPLETE - Waiting for Operational status

22-01-2026 19:24:20 notice DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:24:17 notice TLV-11 - unrecognized OID;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:24:14 warning DHCP WARNING - Non-critical field invalid in response ;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:24:12 notice Honoring MDD; IP provisioning mode = IPv4

22-01-2026 19:24:01 critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:23:59 critical Cable Modem Reboot because of - Reboot UI

22-01-2026 19:15:56 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:15:46 critical No UCDs Received - Timeout;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 19:15:30 critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 13:52:18 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 13:52:18 critical No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 13:51:44 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 13:51:42 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 13:51:42 critical 16 consecutive T3 timeouts while trying to range on upstream channel 4;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 12:56:28 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 01:11:30 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 01:11:29 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

22-01-2026 01:11:29 critical 16 consecutive T3 timeouts while trying to range on upstream channel 4;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

21-01-2026 15:49:14 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

20-01-2026 23:10:50 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

20-01-2026 23:10:48 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

20-01-2026 23:10:48 critical 16 consecutive T3 timeouts while trying to range on upstream channel 4;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

20-01-2026 23:10:42 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

1 Reply

  • Tudor's avatar
    Tudor
    Very Insightful Person
    4 hours ago

    Stats are very good, only 1 upstream channel with some T3 errors, but some of the downstream channels power levels are too high. If you get obvious faults, not just some T3 errors and log messages then follow this. 

    Check with Area faults on 0800 561 0061 If you have a VM landline 150 this goes down to post code level. You could also try the web service status page, but this is not recommended as it only covers issues that affect a very large number of customers.

    VM will not dispatch any technicians while an area fault exists.

    If no area faults found:

    The primary place to report faults or for service requests is Customer Services on 0345 454 1111/150 if you have a VM landline or wait two or three days for a VM staff member to get to your post. This board is not a fault reporting system nor a direct line to VM.