16 Consecutive T3 Timeouts Causing Internet Blips

[avi68]

Hi,

At very random times I lose service for a few minutes. This doesnt happen everyday or every week, it happens very randomly. Looking at the hub 5 logs I see this message "16 consecutive T3 timeouts while trying to range on upstream channel 8". 

Looking closer it seems to be related to the docsis 3.1 upstream channel. For some unknown reason a large number of timeouts occur which takes the internet down for a few minutes. Ive been on the phone with CS who dont really have an idea of what I was talking about. I would like to know what causes these consecutive T3 timeouts and if anyone else with a hub 5 has similar issues?

Reboots and factory resets dont work. Ive already had a few hub 5's and new cables, the issue still occurs. 

Neighbours that I talk to have hub 3's and they dont get these interruptions when I get mine and Im assuming this is because they're using docsis 3.0 channels?

Any advise would be appreciated.

Thanks

[avi68]

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	331000000	6.9	41	QAM 256	25
2	139000000	8.2	40	QAM 256	1
3	147000000	8.2	40	QAM 256	2
4	155000000	8.1	40	QAM 256	3
5	163000000	8	39	QAM 256	4
6	171000000	7.8	39	QAM 256	5
7	179000000	7.7	39	QAM 256	6
8	187000000	7.5	39	QAM 256	7
9	195000000	7.4	39	QAM 256	8
10	203000000	7.3	39	QAM 256	9
11	211000000	7.5	39	QAM 256	10
12	219000000	7.6	38	QAM 256	11
13	227000000	7.5	38	QAM 256	12
14	235000000	7.4	38	QAM 256	13
15	243000000	7	38	QAM 256	14
16	251000000	6.9	39	QAM 256	15
17	259000000	6.6	39	QAM 256	16
18	267000000	6.7	39	QAM 256	17
19	275000000	6.4	39	QAM 256	18
20	283000000	6.5	39	QAM 256	19
21	291000000	6.4	40	QAM 256	20
22	299000000	6.7	40	QAM 256	21
23	307000000	6.8	40	QAM 256	22
24	315000000	7	40	QAM 256	23
25	323000000	6.9	41	QAM 256	24
26	339000000	6.8	41	QAM 256	26
27	347000000	6.6	41	QAM 256	27
28	355000000	6.2	41	QAM 256	28
29	363000000	6.1	41	QAM 256	29
30	371000000	6.5	41	QAM 256	30
31	379000000	6.6	41	QAM 256	31

3.0 Downstream channels

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

1	Locked	41	188	0
2	Locked	40	341	0
3	Locked	40	221	0
4	Locked	40	196	0
5	Locked	39	244	0
6	Locked	39	221	0
7	Locked	39	207	0
8	Locked	39	210	0
9	Locked	39	230	0
10	Locked	39	229	0
11	Locked	39	281	0
12	Locked	38	351	0
13	Locked	38	355	0
14	Locked	38	324	0
15	Locked	38	305	0
16	Locked	39	261	0
17	Locked	39	257	0
18	Locked	39	244	0
19	Locked	39	219	0
20	Locked	39	200	0
21	Locked	40	198	0
22	Locked	40	176	0
23	Locked	40	211	0
24	Locked	40	280	0
25	Locked	41	214	0
26	Locked	41	213	0
27	Locked	41	156	0
28	Locked	41	150	0
29	Locked	41	165	0
30	Locked	41	208	0
31	Locked	41	207	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

41

5.3

2812500725

17

3.0 Upstream channels

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

0	49600000	46.3	5120	QAM 32	1
1	43100000	46.3	5120	QAM 32	2
2	36600000	46	5120	QAM 32	3
3	30100000	45.8	5120	QAM 32	4
4	23600000	45.5	5120	QAM 32	5

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	28	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

11

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

220

74000000

58

0

[avi68]

Network Log

Time	Priority	Description
29-04-2024 13:07:04	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
29-04-2024 13:02:01	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
29-04-2024 07:38:29	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
29-04-2024 07:33:26	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
29-04-2024 00:25:30	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 23:21:41	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 23:06:34	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 23:01:31	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 18:02:37	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 16:58:44	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 16:58:35	critical	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 16:58:35	critical	16 consecutive T3 timeouts while trying to range on upstream channel 8;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
28-04-2024 16:57:27	critical	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 20:50:01	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 20:44:58	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 17:15:29	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 17:10:26	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 17:01:17	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 16:56:14	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 16:52:19	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 16:47:16	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 14:56:32	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 14:51:29	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 11:31:06	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 11:18:28	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 11:07:26	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 11:02:23	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 10:43:19	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 10:38:16	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
27-04-2024 10:13:19	error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
26-04-2024 21:34:12	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
26-04-2024 21:24:03	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=.;CMTS-MAC=.;CM-QOS=1.1;CM-VER=3.1;
26-04-2024 04:44:02	notice	GUI Login Status - Login Success from LAN interface

[avi68]

BQM Blip on Sunday at 5pm:

[Cardiffman282]

All of the upstream power levels are half of what they should be. The BQM suggests some local congregation perhaps. I'd report it as a fault after checking for local faults on 0800 561 0061. 

[avi68]

This is what seems to happen, the modulation fluctuates between 32 and 64QAM. When I check my neighbours hub 3, one of his upstream is on 32 and the rest are on 64. When the noise clears, my upstream goes back to normal and that one upstream channel on my neighbours hub goes back to normal too. Nothing being reported on that number. CS say they cant see any issues. Ive had multiple engineers attend in the past but everything to them is "normal". Its like an ongoing circle. 

[roodles]

I'm here as I was about to start my own thread on "16 consecutive T3 timeouts while trying to range on upstream channel", and it showed me this one.

This happened to me yesterday (Sunday) and I had quite poor stats to go with it:

BQM 

[avi68]

I also searched up ""16 consecutive T3 timeouts" but I didnt get much information. Glad Im not the only one having issues. The last bunch of timeouts happened on Sunday afternoon at 5pm. What time did yours occur? (I doubt we'd have them at the same time)

[Zach_R]

Hi @avi68,

Thank you for your posts and welcome back to our community forums. We're here to help.
 

I'm sorry to hear of your recent connection issues. I've just checked over things on our systems and I'm unable to detect any faults currently that would explain this. Are things any better for you today? If not, would you mind clarifying any troubleshooting that you've carried out so far?

Thanks,
 

[avi68]

Hi Zach,

Its not about the connection being any better, most of the time the connection is fine. What I want to establish is why the hub drops off virgin's network and causes a small outage/blip whilst it tries to reconnect. Looking at the log the culprit is "16 Consecutive T3 Timeouts" which happens on the docsis 3.1 upstream channel. 

In terms of troubleshooting, connections are all tight, no ones moved the cables/router, the router has been reset a few times before and Ive just rebooted it yesterday. But like I said in my original OP, it can happen very randomly. The Hub 3's on my road do not suffer from these "blips" because they dont use docsis3.1 channels. 

Ive also started to notice the modulation starting to dip randomly on all my upstream channels, whilst this happens, my neighbours hub 3 does the same which again points to something with the cab/further down the line.