Upstream Modulation Changing

[avi68]

Hi,

I have a Hub 5 in modem mode. Ive noticed that the Upstream modulation has started to fluctuate between 32QAM and 64QAM. This has been happening for over a month now. Initially the modulation would drop to 16QAM and stay between 16 and 32. However, more recently its been sticking at 32QAM, then jumping to 64 and then going back to 32.

Speeds seem to be ok but I have started to notice random packet loss. Last Thursday evening packet loss was very bad but it seems to have stabilised. I have called CS multiple times but the script they follow doesnt seem to have an answer to my issue. Packet loss is still occurring, not as bad, just small amounts randomly. Dont know if anyone can see an issue with my levels?

Cable Modem Status
Item	Status	Type
Cable Modem Status	Online	DOCSIS 3.0
Primary downstream channel	Locked	SC-QAM
Channel Overview	Downstream	Upstream
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	9.4	40	QAM 256	1
3	147000000	9.3	40	QAM 256	2
4	155000000	9.2	40	QAM 256	3
5	163000000	8.9	40	QAM 256	4
6	171000000	8.8	39	QAM 256	5
7	179000000	8.5	39	QAM 256	6
8	187000000	8.4	39	QAM 256	7
9	195000000	8.3	39	QAM 256	8
10	203000000	8.1	39	QAM 256	9
11	211000000	8.2	39	QAM 256	10
12	219000000	8.1	39	QAM 256	11
13	227000000	7.8	38	QAM 256	12
14	235000000	7.6	38	QAM 256	13
15	243000000	7.3	38	QAM 256	14
16	251000000	7	39	QAM 256	15
17	259000000	6.8	39	QAM 256	16
18	267000000	6.7	39	QAM 256	17
19	275000000	6.6	39	QAM 256	18
20	283000000	6.5	40	QAM 256	19
21	291000000	6.7	40	QAM 256	20
22	299000000	6.7	40	QAM 256	21
23	307000000	7	40	QAM 256	22
24	315000000	7	40	QAM 256	23
25	323000000	7.1	41	QAM 256	24
26	339000000	7	41	QAM 256	26
27	347000000	6.7	41	QAM 256	27
28	355000000	6.7	41	QAM 256	28
29	363000000	6.5	41	QAM 256	29
30	371000000	6.5	41	QAM 256	30
31	379000000	6.5	41	QAM 256	31

3.0 Downstream channels

Channel	Locked Status	RxMER (dB)	Pre RS Errors	Post RS Errors
1	Locked	41	52	0
2	Locked	40	0	0
3	Locked	40	0	0
4	Locked	40	0	0
5	Locked	40	0	0
6	Locked	39	1	0
7	Locked	39	0	0
8	Locked	39	0	0
9	Locked	39	6	0
10	Locked	39	6	0
11	Locked	39	18	0
12	Locked	39	10	0
13	Locked	38	17	0
14	Locked	38	21	0
15	Locked	38	29	0
16	Locked	39	39	0
17	Locked	39	50	0
18	Locked	39	98	0
19	Locked	39	116	0
20	Locked	40	115	0
21	Locked	40	60	0
22	Locked	40	73	0
23	Locked	40	55	0
24	Locked	40	73	0
25	Locked	41	47	0
26	Locked	41	45	0
27	Locked	41	95	0
28	Locked	41	81	0
29	Locked	41	123	0
30	Locked	41	126	0
31	Locked	41	156	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	4.9	809061304	65

3.0 Upstream channels

Channel	Frequency (Hz)	Power (dBmV)	Symbol Rate (ksps)	Modulation	Channel ID
0	49600000	44.5	5120	QAM 32	1
1	43100000	44.3	5120	QAM 32	2
2	36600000	44.3	5120	QAM 32	3
3	30100000	44	5120	QAM 32	4
4	23600000	43.8	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	9	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	11	40.0	2K	QAM 256

3.1 Upstream channels

Channel	Channel Type	Number of Active Subcarriers	First Active Subcarrier (Hz)	T3 Timeouts	T4 Timeouts
6	OFDMA	220	74000000	0	0

[avi68]

Network Log

Time	Priority	Description
22-01-2024 13:35:27	error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=-;CMTS-MAC=-;CM-QOS=1.1;CM-VER=3.1;
21-01-2024 14:46:38	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;
21-01-2024 12:39:00	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;
20-01-2024 11:04:39	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;
19-01-2024 22:18:56	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;
19-01-2024 14:52:15	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;
19-01-2024 12:44:38	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;
19-01-2024 10:37:01	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;
19-01-2024 10:26:05	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;
19-01-2024 10:21:02	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;
19-01-2024 01:35:26	error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=-;CMTS-MAC=-;CM-QOS=1.1;CM-VER=3.1;
18-01-2024 23:30:23	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;
18-01-2024 23:25:20	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;
18-01-2024 22:46:04	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;
18-01-2024 22:41:01	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;
18-01-2024 22:39:51	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;
18-01-2024 22:34:48	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;
18-01-2024 22:31:02	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;
18-01-2024 22:25:59	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;
18-01-2024 22:15:04	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;
18-01-2024 22:10:01	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;
18-01-2024 22:08:11	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;
18-01-2024 22:03:08	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;
18-01-2024 21:53:50	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;
18-01-2024 21:48:47	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;
18-01-2024 21:44:30	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;
18-01-2024 21:39:27	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;
18-01-2024 21:29:40	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;
18-01-2024 21:24:37	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;
18-01-2024 21:17:23	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;
18-01-2024 21:12:20	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;
18-01-2024 21:10:50	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;

Thanks 

[avi68]

Todays BQM:

https://www.thinkbroadband.com/broadband/monitoring/quality/share/592c4f47b1e1cfa6df543480d7fa9299ba...

 Last thursday:

https://www.thinkbroadband.com/broadband/monitoring/quality/share/583524890934147e39e788e30a8245e22adf74fc-18-01-2024

[Kath_F]

Hi avi68, 

Thanks for taking the time to contact us via the Community. It's lovely having you on board with us in the Forums. ⭐

We're sorry to hear you've been having an issue with your service. I've taken a look at the hub at this end and I can see your downstream power levels are very slightly too high. Given the fact to hub is also switching between the 32QAM and 64QAM, I would like to arrange for an engineer to come to take a look at this for you. 

I just need to confirm the address to ensure we are booking the visit on the correct account. I have sent you a direct message to allow us to do this with you in a private space. If you are using a PC/Laptop then you can just click on the little ✉ at the top right-hand side of the page to access your inbox. If you are on a mobile/tablet device then instead click on the little circle icon in the top right then select 'Messages'. 😊

Thanks,

[avi68]

Thanks for your reply kath. I have messaged you back.

[Kath_F]

Hi avi68, 

Thanks for coming back to via private message to confirm your information. 🤩

I have booked you in for the next available appointment. To view this please sign in to My Virgin Media here 👉 My VM. Once you log in scroll down to Orders & appointments then click on View your orders. Please note it can take up to 24 hours to show but you should also receive a text message with the details. You can also view this in the My VM app. If you have any issues with accessing your account or unable to see your visit, please do let us know and we’ll pop you a message to pass data protection and confirm the appointment details.

Just to confirm, there will be no charge for this visit unless:

• ➡ The technician diagnoses the faults as not being caused by our network/equipment
• ➡ The technician discovers that the fault or problem relates to your equipment
• ➡ The technician discovers that the fault or problem relates to any system that we are not responsible for
• ➡ The technician will confirm during their visit if any of these instances apply, and if so, a £25 charge will be applied to your account.

Please ensure there is someone over the age of 18 present at the time of the visit. If you need to change or cancel your appointment you can do this online or via the MyVM app by 4pm the day before the appointment. If you do miss an agreed appointment for any reason, a £25 missed appointment charge will be applied to your account on the day of the appointment.

We will continue to monitor your services and if we can see that the fault has cleared and the visit is no longer required we will cancel the appointment and let you know by text and email.

Let us know how the appointment goes. 😊

Take care.

[avi68]

Thank you

[avi68]

Engineer visited on Tuesday, checked the power levels coming in and confirmed they were already in spec. I mentioned an ongoing issue with the street cabinet. He has raised this and Im hoping that Networks will come and tidy up the cabinet (this has probably been the 8th time Ive mentioned the state of the cabinet to a number of engineers). 

Everything was working well until yesterday evening at 8:22 when my connection went down (both Wired and wireless). I looked at the hub 5 logs and it showed "16 consecutive T3 timeouts". Something still isnt right. 

Logs:

31-01-2024 20:23:01	critical	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
31-01-2024 20:23:01	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;
31-01-2024 20:21:53	critical	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;

Upstream 3.1 channel is where the timeouts occurred

3.0 Upstream channels

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

0	49600000	44.5	5120	QAM 64	1
1	43100000	44.5	5120	QAM 64	2
2	36600000	44.3	5120	QAM 64	3
3	30100000	44.3	5120	QAM 64	4
4	23600000	44	5120	QAM 64	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	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

11

40.0

2K

QAM 256

3.1 Upstream channels

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

6

OFDMA

220

74000000

18

0

[Kath_F]

Hi avi68, 

Thanks for coming back and updating us on how the visit went.

Our diagnostics on your home network and Hub have not found any issues that could account for the issues you're having. This means that the issues are most likely due to the equipment being used in the home. We can see you're using a third party router with the hub in modem mode. 

Can you take this out of the equation and pop the hub into it's usual router mode to see if the issues continue when connecting in this way?

Keep us posted on how things go. 

Thanks, 

[avi68]

Hi Kath,

I have already tried this before and it has not made any difference. Although this issue isnt constantly happening it does happen very randomly and its annoying when it does because it takes down everything (wired and wireless connections).

I understand its easy to blame customer equipment but in this case, as you can see from the logs, the hub is timing out which shows that there is an issue between the hub and virgin media's network. My router isnt timing out or dropping out, its your side. Why would my own router logs show "16 consecutive T3 timeouts"? This can be seen from the hub 5 logs.

I have been monitoring my neighbours virgin media connection and he hasnt had a bunch of T3 timeouts in one go (he has lots of T3 timeouts but not all occurring at once) but he has a hub3. Ive noticed that the large amount of timeouts seem to occur on the 3.1 upstream channel (which the hub3's do not use). Surely there must be something causing those timeouts? 

Could you explain what "16 consecutive T3 timeouts" means?

I also had a random reboot the morning at 2:50am, but in the log it just says reboot due to unknown. Firmware level is still the same and there has been no power cut.

Looking forward to your reply.

Thanks