Connection bouncing intermittently, suspect DOCSIS 3.1 levels

[fatedsnowfox]

Hi!

Been a long time since I posted here!  Been having an issue with my connection pretty much from when it was installed.  It will intermittently start bouncing up and down - last night was particularly bad, with 26 interruptions in the space of an hour. Looking at the stats I think our DOCSIS 3.1 levels are out of spec and we have a fault - our PLC power is -15.5DBmV where I think the spec is like supposed to be -6 to +10DBmV.  Full logs below! :

Cable Modem StatusItem Status TypeChannel Overview Downstream Upstream

Cable Modem Status	Online	DOCSIS 3.0
Primary downstream channel	Locked	SC-QAM
DOCSIS 3.0 channels	31	5
DOCSIS 3.1 channels	1	1

3.0 Downstream channels

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

1	339000000	-6.5	39	QAM 256	26
2	139000000	0.3	40	QAM 256	1
3	147000000	0.2	40	QAM 256	2
4	155000000	0.5	40	QAM 256	3
5	163000000	0.9	40	QAM 256	4
6	171000000	-1.4	40	QAM 256	5
7	179000000	-1.9	40	QAM 256	6
8	187000000	-2.2	40	QAM 256	7
9	195000000	-2.2	40	QAM 256	8
10	203000000	-2.5	40	QAM 256	9
11	211000000	-2.8	40	QAM 256	10
12	219000000	-3.2	40	QAM 256	11
13	227000000	-3.9	40	QAM 256	12
14	235000000	-4	40	QAM 256	13
15	251000000	-4.6	40	QAM 256	15
16	259000000	-4.7	40	QAM 256	16
17	267000000	-4.8	40	QAM 256	17
18	275000000	-4.8	40	QAM 256	18
19	283000000	-4.9	40	QAM 256	19
20	291000000	-5.1	40	QAM 256	20
21	299000000	-5.3	40	QAM 256	21
22	307000000	-5.8	40	QAM 256	22
23	315000000	-5.9	40	QAM 256	23
24	323000000	-6.3	40	QAM 256	24
25	331000000	-6.4	40	QAM 256	25
26	347000000	-7	39	QAM 256	27
27	355000000	-6.9	40	QAM 256	28
28	363000000	-6.9	40	QAM 256	29
29	371000000	-7.3	39	QAM 256	30
30	379000000	-7.6	39	QAM 256	31
31	387000000	-8.3	39	QAM 256	32

3.0 Downstream channels

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

1	Locked	39	88	0
2	Locked	40	35	0
3	Locked	40	36	0
4	Locked	40	33	0
5	Locked	40	19	0
6	Locked	40	63	0
7	Locked	40	112	0
8	Locked	40	41	0
9	Locked	40	30	0
10	Locked	40	36	0
11	Locked	40	26	0
12	Locked	40	23	0
13	Locked	40	28	0
14	Locked	40	37	0
15	Locked	40	30	0
16	Locked	40	46	0
17	Locked	40	69	0
18	Locked	40	73	0
19	Locked	40	65	0
20	Locked	40	34	0
21	Locked	40	28	0
22	Locked	40	53	0
23	Locked	40	59	0
24	Locked	40	72	0
25	Locked	40	73	0
26	Locked	39	111	0
27	Locked	40	102	0
28	Locked	40	104	0
29	Locked	39	177	0
30	Locked	39	223	0
31	Locked	39	398	0

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

35

-15.5

611240571

7827454

3.0 Upstream channels

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

0	49600000	45.8	5120	QAM 64	1
1	43100000	45.8	5120	QAM 64	2
2	36600000	45.8	5120	QAM 64	3
3	30100000	45.8	5120	QAM 64	4
4	23600000	45.8	5120	QAM 64	5

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

0	ATDMA	0	0	5	0
1	ATDMA	0	0	3	0
2	ATDMA	0	0	0	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

6

10.4

41.2

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

0

0

General Configuration

Network accessMaximum Number of CPEsBaseline PrivacyDOCSIS ModeConfig file

Allowed

1

Enabled

3.1

cmreg-vmdg660-bbt076-b.cm

Primary Downstream Service Flow

SFIDMax Traffic RateMax Traffic BurstMin Traffic Rate

35890

1230000450 bps

42600bytes

0 bps

Primary Upstream Service Flow

SFIDMax Traffic RateMax Traffic BurstMin Traffic RateMax Concatenated BurstScheduling Type

35889

110000274 bps

42600bytes

0 bps

42600bytes

Best Effort

[fatedsnowfox]

Full network log:

Time Priority Description

12-08-2024 07:13:35	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 07:08:40	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:54:14	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:49:02	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:37:08	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:27:31	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:20:07	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:15:23	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:08:12	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 06:04:24	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:55:35	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:36:03	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:34:14	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:33:26	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:30:55	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:24:13	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 05:12:11	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:47:37	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:44:02	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:37:00	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:34:22	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:32:31	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:23:55	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:21:45	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:18:27	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 04:02:05	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 03:54:58	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 03:47:33	notice	CM-STATUS message sent. Event Type Code: 24; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 02:30:21	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 01:40:41	critical	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 01:30:26	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 01:17:25	critical	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

[Client62]

It would be best to phone in the fault and request an engineer visit to address the far too low 3.1 Downstream power levels & errors, but also note the 3.0 Downstream power levels have and unusually large spread across the channels.

[fatedsnowfox]

Getting absolutely nowhere with telephone support.  "Factory resetting your superhub will fix it."  It's good to know that in the time I've been away, the call centre hasn't changed. 

[fatedsnowfox]

Logs and stats after the factory reset: 

Network Log

Time Priority Description

12-08-2024 12:47:17	notice	CM-STATUS message sent. Event Type Code: 16; Chan ID: 33; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:46:46	notice	REGISTRATION COMPLETE - Waiting for Operational status
12-08-2024 12:46:42	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:46:36	notice	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:46:33	notice	TLV-11 - unrecognized OID;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:46:30	warning	DHCP WARNING - Non-critical field invalid in response ;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:46:28	notice	Honoring MDD; IP provisioning mode = IPv4
12-08-2024 12:46:10	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:46:09	critical	Cable Modem Reboot because of - Erouter Mode Change
12-08-2024 12:39:27	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
12-08-2024 12:39:26	critical	Cable Modem Reboot because of - Reboot Timezone Change
12-08-2024 12:36:19	critical	Cable Modem Reboot because of - pin-reset
12-08-2024 12:36:19	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

[fatedsnowfox]

Note that the voltages haven't changed and the uncorrectable errors are already shooting up -

3.0 Downstream channels

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

1	331000000	-6.2	40	QAM 256	25
2	139000000	0.6	40	QAM 256	1
3	147000000	0.1	40	QAM 256	2
4	155000000	0.3	40	QAM 256	3
5	163000000	0.7	40	QAM 256	4
6	179000000	-1.6	40	QAM 256	6
7	187000000	-2	40	QAM 256	7
8	195000000	-2	40	QAM 256	8
9	203000000	-2.3	40	QAM 256	9
10	211000000	-2.5	40	QAM 256	10
11	219000000	-3	40	QAM 256	11
12	227000000	-3.7	40	QAM 256	12
13	235000000	-3.8	40	QAM 256	13
14	243000000	-4	40	QAM 256	14
15	251000000	-4.4	40	QAM 256	15
16	259000000	-4.6	40	QAM 256	16
17	267000000	-4.7	40	QAM 256	17
18	275000000	-4.6	40	QAM 256	18
19	283000000	-4.7	40	QAM 256	19
20	291000000	-4.9	40	QAM 256	20
21	299000000	-5.1	40	QAM 256	21
22	307000000	-5.7	40	QAM 256	22
23	315000000	-5.7	40	QAM 256	23
24	323000000	-6.1	40	QAM 256	24
25	339000000	-6.4	40	QAM 256	26
26	347000000	-6.7	40	QAM 256	27
27	355000000	-6.6	40	QAM 256	28
28	363000000	-6.7	40	QAM 256	29
29	371000000	-7.1	39	QAM 256	30
30	379000000	-7.3	39	QAM 256	31
31	387000000	-8	39	QAM 256	32

3.0 Downstream channels

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

1	Locked	40	0	0
2	Locked	40	0	0
3	Locked	40	0	0
4	Locked	40	0	0
5	Locked	40	0	0
6	Locked	40	0	0
7	Locked	40	0	0
8	Locked	40	0	0
9	Locked	40	0	0
10	Locked	40	0	0
11	Locked	40	0	0
12	Locked	40	0	0
13	Locked	40	0	0
14	Locked	40	0	0
15	Locked	40	0	0
16	Locked	40	0	0
17	Locked	40	0	0
18	Locked	40	0	0
19	Locked	40	0	0
20	Locked	40	0	0
21	Locked	40	0	0
22	Locked	40	0	0
23	Locked	40	0	0
24	Locked	40	0	0
25	Locked	40	0	0
26	Locked	40	0	0
27	Locked	40	0	0
28	Locked	40	0	0
29	Locked	39	0	0
30	Locked	39	0	0
31	Locked	39	0	0

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

35

-15.5

1673083

217827

[Tom_W1]

Hi @fatedsnowfox thanks for your post although we're sorry to hear of your concerns raised.

We can see there's some issues with the power levels so we'll need to look at sending an engineer out to resolving this but please let me send you a PM so we can look into this further.

Kindly expect the PM from me to arrive shortly and respond directly when you can!
Many thanks