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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

 

31 REPLIES 31

Thanks for coming back to is avi68, I can see that you have been able to get a technician visit booked in to look into these issues.

Please let us know how the visit goes and I hope that we can get this resolved for you.

Kind Regards,

Steven_L

Hi Steven, 

The technician visit is for another issue thats started to occur (random reboots on Tue, Wed, Thurs morning between 2-3am). Very odd that CS have arranged a tech visit for this when it doesnt seem to be isolated just to me. I have seen a few posts on this forum showing other users having the same issue.

In all honesty I doubt the tech will do anything, as Ive had multiple visits and there are still random issues occurring with my connection. Going back to my previous post could you tell me what the following means : "16 consecutive T3 timeouts" ? 

As stated in my previous post I get these randomly on the 3.1 upstream channel.

Thanks for coming back to us @avi68, and I'm sorry to hear that this issue is still ongoing.

I understand that our Networks team are looking into issues in your local area and will be sure to update all effected customers as soon as possible.

Do please keep tabs on our Service Status Checker https://virg.in/service or call our Service Status Line 0800 561 0061 for an update on any outages that are raised.

Thanks,

David_Bn

Hi David,

After multiple engineer visits, the networks team have finally acknowledged a problem which is affecting my whole area. Im disappointed that Ive had to explain my issues multiple times to multiple engineers /CS agents as no one would believe me. 

I do hope these issues get addressed quickly. 

Thanks

avi68
Dialled in

Hub 5 rebooted again this morning at 2am. Log says reboot due to unknown. 

Hey Avid68, thank you for reaching out and I am sorry to hear this.

I have checked from our end and I can see you've spoke to someone since this post, did they manage to help at all?

Matt - Forum Team


New around here?

Hi Matthew,

Not really, they tried to go through their script again but when I told them to read the account notes they said its currently with the networks team. As of yet Im waiting for an update. The modem rebooted on Tuesday and Wednesday morning at 2am. Interestingly, it didnt reboot this morning. Normally it reboots on Tues,Wed,Thursday mornings. 

Is there a way you could get an update from networks?

Hey there @avi68 Thanks for reaching out to us on the Virgin Media forums. 👋🏼

Are you on the trial for the XGS-PON network?
With the hub you have, have you tried to ring in to our ring fence team?

Kind regards,
Ilyas.

Ilyas_Y
Forum Team

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


Hi Ilyas, 

No Im not. Im using a normal hub 5 and I am on your coaxial service. Who are the ring fence team?

avi68
Dialled in

Another reboot this morning, hub 5 logs:

20-02-2024 02:55:01noticeREGISTRATION COMPLETE - Waiting for Operational status
20-02-2024 02:54:57noticeUS profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
20-02-2024 02:54:51noticeDS 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;
20-02-2024 02:54:48noticeTLV-11 - unrecognized OID;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
20-02-2024 02:54:45warningDHCP WARNING - Non-critical field invalid in response ;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
20-02-2024 02:54:43noticeHonoring MDD; IP provisioning mode = IPv4
20-02-2024 02:54:26criticalSYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
20-02-2024 02:54:25criticalCable Modem Reboot because of - unknown