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

Imo, Martin should have said that there is noise on your upstream (which you at least have grasped) and as you neighbour has a similar symptom, there is likely to be an area fault. A repeated fault needs attention.The problem in getting this noise resolved is that the shifting QAM modulation is standard behaviour because the level is set to take noise into account. The Forum Team are thus not interested in changes of QAM modulation.Of course a more significant noise ingress can cause an upstream channel to fail. In your case, the keep-alive message on your then broken upstream channel failed 16x times and there would have bee a T4 event - modem reset.All that the Community can do is interpret what's going on. You really are in VM's hands here and until they recognise that your T4 events are a serious matter and that it affects neighbours, you're lumbered with the problem.

A little update for those watching this thread:So after raising a complaint I got a call back from the complaints team. I explained the issues and the representative raised it with the local networks team. I saw a networks engineer down my road on Thursday and I wanted to have a chat with him but he was busy on the phone. I then got a phone call on Friday morning, the complaints team called as they just received an email from the networks team with their findings. They found an issue with the power levels at the cab, which they have adjusted and bought in spec. So far, the modulation on the upstream channels have stayed at 64qam, even on the weekends (where previously they were dipping). So far I haven't had any "16 consecutive t3 timeouts" but its too early to tell. Ill be monitoring the connection for the next week or 2. Hoping its all fixed (fingers crossed).I did have a bit of packet loss (to virgin media's gateway) on Friday evening, Saturday evening and Sunday afternoon. These were very small but they have started to appear. Again Ill be keeping an eye and Ill update the complaints team when they call me in a weeks time.Thanks to all that have helped on this thread with advice and knowledge, really appreciate it.

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.

Each case is unique unless you are on the same network segment as someone else with the same issue.The Community here can help you pin this down if you post your upstream/downstream stats and the network log. If there is a line impairment, for whatever reason, you're well likely to get 16x T3 events followed by a Hub reset.The Hub 4 is orders of magnitude better than the Hub 3. Btw, the Forum Team , when they come to look at your circuit, are unlikely to find anything wrong unless they catch it at the right moment. These are difficult cases.

Another update:I had a networks engineer and normal engineer attend today. They finally looked at the correct cabinet and found some issues. As previous engineers stated, the cabinet was in a mess and the cable coming into the cab was damaged.The network engineer repaired the damaged cable coming into the cabinet, also repaired a few other cables within the cab and lastly found a splitter that was not working correctly. There was around an hour downtime this morning whilst he was working on the cab and after that all my power levels shot up to over 10. The engineer came back and added a different anntenuator on the coax cable to reduce the power. So now I will continue to monitor. Fingers crossed I hope everything's fixed. (after years of complaining about noise)

16 Consecutive T3 Timeouts Causing Internet Blips | Virgin Media Community

101 Replies

avi68

Superfast

12 months ago

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

3.1 Downstream channels

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

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)

Locked

5.3

2812500725

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
1	ATDMA	0
2	ATDMA	28
3	ATDMA	0
4	ATDMA	0

3.1 Upstream channels

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

41.2

QAM 256

3.1 Upstream channels

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

OFDMA

220

74000000

avi68

Superfast

12 months ago

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
Superfast
12 months ago
BQM Blip on Sunday at 5pm:
- Cardiffman282
  Wise owl
  12 months ago
  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
    Superfast
    12 months ago
    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
Dialled in
12 months ago
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
  Superfast
  12 months ago
  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
    Forum Team (Retired)
    12 months ago
    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,
Sephiroth
Alessandro Volta
12 months ago
Imo, Martin should have said that there is noise on your upstream (which you at least have grasped) and as you neighbour has a similar symptom, there is likely to be an area fault. A repeated fault needs attention.
The problem in getting this noise resolved is that the shifting QAM modulation is standard behaviour because the level is set to take noise into account. The Forum Team are thus not interested in changes of QAM modulation.
Of course a more significant noise ingress can cause an upstream channel to fail. In your case, the keep-alive message on your then broken upstream channel failed 16x times and there would have bee a T4 event - modem reset.
All that the Community can do is interpret what's going on. You really are in VM's hands here and until they recognise that your T4 events are a serious matter and that it affects neighbours, you're lumbered with the problem.
- avi68
  Superfast
  12 months ago
  Thanks for the explanation Seph. Thats pretty much what I was looking for. Unfortunately VM dont seem to want to do anything, I think Im going to have to get more people in my area to complain before we finally see any results.
  Interestingly, one of the engineers that came last time said he saw some noise on the cable and then it went, which explains why the modulation keeps dipping and then coming back. I even had another engineer make me replace all the internal wiring because he thought it was the wire. Clearly there is something going on further down the line, I think I require a senior engineer or even an area manager to contact me. I doubt this will happen but I guess Ill have to wait and see.
Sephiroth
Alessandro Volta
12 months ago
Transient noise - the sort of thing that causes that is a noisy electrical device kicking in somewhere in the locality which issues RF interference that hits either someone's hub or the coax cable. Once it's hit your locality, everyone on that segment will experience the noise and their modulation will drop. When the noise goes (like the fridge motor cuts out), the modulation will rise. Sometimes the noise hits the coax cable because there is an unterminated endpoint - as in a splitter. A 75 ohm terminator needs to go on every unterminated point and it would be VM's duty to do this on their equipment/splitter (and they usually do). Is there a CB Radio aerial atop any of the houses near you?
The VM tech attending just needs to catch it.
- avi68
  Superfast
  12 months ago
  I cant see any CB Radio aerials nearby. I do live near Heathrow airport though (few miles away), not sure if that could be the cause?
  Ive had a few engineers attend and look at the green cabinet, apparently its in a bad state. The incoming coax is severed/damaged, the main components are not screwed to the back board and are twisted within the cables. Another engineer said they need to remove cables from the customers that are no longer with them as that could be causing issues.
  Getting someone to attend to sort this is such a hassle. Previous engineers have reported it but as usual nothings happened.
  - Sephiroth
    Alessandro Volta
    12 months ago
    Any damaged coax that's not in a Faraday cage (e.g. the intact, closed cabinet) can pick up RF noise. The engineer is right about removing cables (and terminating the open tap points). It's a good bet.
avi68
Superfast
12 months ago
Engineer attended and he believes that the drop wire needs replacing (really odd as this was just recently replaced in the last few years). Power levels are all ok but he could see noise ingress on the cable itself (he tested the cable).
Waiting for him to confirm his findings with his manager before I get notified on the next steps.
@Martin_N it seems like another "normal" engineer was booked instead of a senior engineer
avi68
Superfast
11 months ago
As expected, changing the cable hasn’t made a difference. As of 7pm today I got the 16 consecutive T3 timeouts error again and the connection dropped.

My third door neighbour who’s also been upgraded to a hub 5 had the exact same issue at the same time. So that’s proved that it’s not the cables, it’s either the cabinet on the road or something at the head end in Hayes which is what I’ve been saying from the beginning but Networks don’t want to do anything.

This needs to be escalated as it’s been on going for months.
avi68
Superfast
11 months ago
Got a response from a forum team member, who’s given me 2 options, can try and cancel without early termination fees or get an engineer sent out.

Funny how they don’t want to get the issue fixed as it isn’t an isolated issue.
I am now going to escalate this further and I’m going to get my neighbours to do the same.
- Vikki_M
  Forum Team
  11 months ago
  Hi avi68
  
  We're sorry to hear this hasn't yet been resolved.
  
  We can see you're already in a private message conversation with a member of the team here.
  
  Please respond there directly if you have any questions or would like to raise a formal complaint and we can help further.
- Matthew_ML
  Forum Team
  11 months ago
  I have replied back to your DM.
  - avi68
    Superfast
    11 months ago
    Thanks
Phybersaur
Tuning in
11 months ago
We were sent a Hub 4 last week (to replace the Hub 3) and we've been having similar issues; multiple times a day, the box will seemingly reboot itself, taking around 5-15 mins to return to operation. Every time it does this, it logs the same four things on the network log, one of which is "16 consecutive T3 timeouts while trying to range on upstream channel 10".
Multiple customer service agents on the phone have struggled to identify the issue, with one using it as an opportunity to sign us up for an upgraded package that did nothing to solve the problem but locked us into 18 months on a more expensive package. 🙈
If you manage to find out what's causing the issue then please let me know. 🙏
- Sephiroth
  Alessandro Volta
  11 months ago
  Each case is unique unless you are on the same network segment as someone else with the same issue.
  The Community here can help you pin this down if you post your upstream/downstream stats and the network log. If there is a line impairment, for whatever reason, you're well likely to get 16x T3 events followed by a Hub reset.
  The Hub 4 is orders of magnitude better than the Hub 3. Btw, the Forum Team , when they come to look at your circuit, are unlikely to find anything wrong unless they catch it at the right moment. These are difficult cases.
- avi68
  Superfast
  11 months ago
  I will keep you updated. Ive never had this issue on the hub 4, since getting a hub 5 this has been happening very randomly.
  
  There is something clearly going on as this isnt the only thread about those timeouts. Other people from different areas have reported the same thing but i have not seen a resolution on any threads at the moment. I have a feeling it’s a bigger issue affecting most if not all customers with hub 5’s. Similar to the hub 5 rebooting on Tuesday, Wednesday and Thursday mornings, I reported this a long time ago, no one would help me, and now by magic that’s fixed itself. Someone has definitely done something to stop the reboots but we won’t know what or who’s fixed it. I think this will be the same, if multiple people complain, something MIGHT get fixed, and we won’t get informed.