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Upstream Modulation Changing

avi68
Dialled in

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

 

24 REPLIES 24

avi68
Dialled in

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
Dialled in

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

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,

Kath_F
Forum Team

New around here? Check out the do's and don'ts, in our Community FAQs


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

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.

Kath_F
Forum Team

New around here? Check out the do's and don'ts, in our Community FAQs


Thank you

avi68
Dialled in

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 20:23:01criticalUnicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
31-01-2024 20:23:01critical16 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 20:21:53criticalStarted Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;

avi68_0-1706788339868.png

Upstream 3.1 channel is where the timeouts occurred

3.0 Upstream channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
04960000044.55120QAM 641
14310000044.55120QAM 642
23660000044.35120QAM 643
33010000044.35120QAM 644
423600000445120QAM 645

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
0ATDMA0000
1ATDMA0000
2ATDMA0000
3ATDMA0000
4ATDMA0000

3.1 Upstream channels

Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation
61140.02KQAM 256

3.1 Upstream channels

Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts
6OFDMA22074000000180

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, 

Kath_F
Forum Team

New around here? Check out the do's and don'ts, in our Community FAQs


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