Intermittent Network - Drop outs

3.1 Downstream channels

Channel    Channel Width (MHz)    FFT Type    Number of Active Subcarriers    Modulation (Active Profile)    First Active Subcarrier (Hz)
33    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)
33    Locked    0    -2.4    2922808415    53932

Refresh data
3.0 Downstream channels

Channel    Frequency (Hz)    Power (dBmV)    SNR (dB)    Modulation    Channel ID
1    347000000    1.8    38    QAM 256    27
2    139000000    0.9    35    QAM 256    1
3    147000000    0.7    35    QAM 256    2
4    155000000    0.7    35    QAM 256    3
5    163000000    0.6    35    QAM 256    4
6    171000000    0.3    36    QAM 256    5
7    179000000    0.1    36    QAM 256    6
8    187000000    0.1    36    QAM 256    7
9    195000000    0.2    36    QAM 256    8
10    211000000    0.4    36    QAM 256    10
11    219000000    0.5    36    QAM 256    11
12    227000000    0.6    36    QAM 256    12
13    235000000    0.3    36    QAM 256    13
14    243000000    0    36    QAM 256    14
15    251000000    0.1    36    QAM 256    15
16    259000000    0.1    36    QAM 256    16
17    267000000    0.1    36    QAM 256    17
18    275000000    0.1    36    QAM 256    18
19    283000000    0.3    37    QAM 256    19
20    291000000    0.6    37    QAM 256    20
21    299000000    1    37    QAM 256    21
22    307000000    1.3    37    QAM 256    22
23    315000000    1.3    37    QAM 256    23
24    323000000    1.4    37    QAM 256    24
25    331000000    1.5    37    QAM 256    25
26    339000000    1.6    37    QAM 256    26
27    355000000    1.8    38    QAM 256    28
28    363000000    1.9    38    QAM 256    29
29    371000000    1.8    38    QAM 256    30
30    379000000    1.8    38    QAM 256    31
31    387000000    1.7    38    QAM 256    32
3.0 Downstream channels

Channel    Locked Status    RxMER (dB)    Pre RS Errors    Post RS Errors
1    Locked    38    95500    1105
2    Locked    35    255209    329296
3    Locked    35    139111    17936
4    Locked    35    246728    309174
5    Locked    35    117065    20392
6    Locked    36    246560    316168
7    Locked    36    220216    294715
8    Locked    36    234967    318835
9    Locked    36    230328    317831
10    Locked    36    100632    27934
11    Locked    36    227678    301555
12    Locked    36    229756    290734
13    Locked    36    243295    255937
14    Locked    36    263127    214616
15    Locked    36    270485    201494
16    Locked    36    275533    191103
17    Locked    36    115692    27852
18    Locked    36    292108    158483
19    Locked    37    197411    53006
20    Locked    37    323657    94098
21    Locked    37    323148    75072
22    Locked    37    234241    35380
23    Locked    37    228224    37779
24    Locked    37    222751    33448
25    Locked    37    171834    31546
26    Locked    37    172322    24512
27    Locked    38    73094    23253
28    Locked    38    78530    23048
29    Locked    38    223927    34360
30    Locked    38    219450    33612
31    Locked    38    205542    32247

3.0 Upstream channels

Channel    Frequency (Hz)    Power (dBmV)    Symbol Rate (ksps)    Modulation    Channel ID
0    49600000    48.8    5120    QAM 64    1
1    43100000    49    5120    QAM 64    2
2    36600000    48.8    5120    QAM 64    3
3    30100000    49.3    5120    QAM 64    4
4    23600000    49.8    5120    QAM 64    5
3.0 Upstream channels

Channel    Channel Type    T1 Timeouts    T2 Timeouts    T3 Timeouts    T4 Timeouts
0    ATDMA    0    1    15    0
1    ATDMA    0    1    2    0
2    ATDMA    0    1    1    0
3    ATDMA    0    1    3    0
4    ATDMA    0    1    12    0
3.1 Upstream channels

Channel    Channel Width (MHz)    Power (dBmV)    FFT Type    Modulation
6    10.4    44.0    2K    QAM 256
3.1 Upstream channels

Channel    Channel Type    Number of Active Subcarriers    First Active Subcarrier (Hz)    T3 Timeouts    T4 Timeouts
6    OFDMA    208    74000000    4    0

General Configuration

Network access    Allowed
Maximum Number of CPEs    3
Baseline Privacy    Enabled
DOCSIS Mode    3.1
Config file    cmreg-vmdg660-bbt062+voc-b.cm
Primary Downstream Service Flow

SFID    50406
Max Traffic Rate    402500089 bps
Max Traffic Burst    42600bytes
Min Traffic Rate    0 bps
SFID    50408
Max Traffic Rate    128000 bps
Max Traffic Burst    3044bytes
Min Traffic Rate    0 bps
Primary Upstream Service Flow

SFID    50405
Max Traffic Rate    38500089 bps
Max Traffic Burst    42600bytes
Min Traffic Rate    0 bps
Max Concatenated Burst    42600bytes
Scheduling Type    Best Effort
SFID    50407
Max Traffic Rate    128000 bps
Max Traffic Burst    3044bytes
Min Traffic Rate    0 bps
Max Concatenated Burst    1522bytes
Scheduling Type    Best Effort

Network Log

Time    Priority    Description
21-07-2025 03:55:12    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
21-07-2025 03:55:12    warning    Dynamic Range Window violation
21-07-2025 01:33:05    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
21-07-2025 01:33:05    warning    Dynamic Range Window violation
21-07-2025 00:06:04    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
21-07-2025 00:06:04    warning    Dynamic Range Window violation
20-07-2025 23:04:37    warning    RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
20-07-2025 23:04:16    notice    CM-STATUS message sent. Event Type Code: 4; Chan ID: 2 3 11 13 15 16 17 18 20 21 24 25 30; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
20-07-2025 23:04:01    notice    CM-STATUS message sent. Event Type Code: 5; Chan ID: 1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.
20-07-2025 23:03:59    warning    MDD message timeout;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
20-07-2025 23:03:57    notice    CM-STATUS message sent. Event Type Code: 2; Chan ID: 2 3 11 13 15 16 17 18 20 21 25; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
19-07-2025 13:37:30    warning    RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
19-07-2025 11:45:21    error    DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
18-07-2025 23:01:34    warning    RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
18-07-2025 21:49:24    critical    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
18-07-2025 14:02:05    warning    RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
18-07-2025 13:59:30    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
18-07-2025 13:59:30    warning    Dynamic Range Window violation
17-07-2025 12:36:45    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
17-07-2025 12:36:45    warning    Dynamic Range Window violation
17-07-2025 04:20:46    warning    Dynamic Range Window violation
17-07-2025 04:20:46    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
17-07-2025 03:02:08    critical    16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
17-07-2025 03:02:08    critical    Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
17-07-2025 03:02:08    critical    No Ranging Response received - T3 time-out;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
17-07-2025 03:02:01    critical    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
16-07-2025 20:42:30    warning    Dynamic Range Window violation
16-07-2025 20:42:30    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
16-07-2025 13:27:26    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;
16-07-2025 13:27:26    warning    Dynamic Range Window violation
15-07-2025 23:46:36    warning    Dynamic Range Window violation
15-07-2025 23:46:36    warning    RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=dc:92:72:56:4b:0d;CMTS-MAC=00:01:5c:97:80:bd;CM-QOS=1.1;CM-VER=3.1;

Hi, I’ve been dealing with a very similar issue; frequent dropouts, high latency, and DOCSIS 3.1 upstream not locking (falling back to 3.0). My BQM shows periods of instability, and the Hub 5 logs are filled with ranging failures (T3/T4 timeouts).

Virgin Media support initially focused on internal wiring and equipment replacement, but the real issue appears to be upstream - possibly signal levels or provisioning at the cabinet or CMTS.

Would be interested to see if you’re seeing similar log entries or BQM results.

https://www.thinkbroadband.com/broadband/monitoring/quality

https://www.thinkbroadband.com/broadband/monitoring/quality/share/baacaa7912823a3d028fcae76b6fb781e71bf154

See above, just note that symptoms don't match the graph, currently on site with Cat 6, ping test and was sitting at 60MS to 8.8.8.8 for some time.

Got it down to a more reasonable 30 but it is extremely jittery.