Unstable connection: Problem with Docsis 3.1?

[Mike14]

Hi

I'm on the 1 Gig service and although speed tests show the speed that i am paying for, I'm experiencing dropped packets which cause video calls to be dropped. An engineer recently visited to fix my landline and said the broadband signal levels look fine, but the stats on my Hub 5, look very unhealthy to me: huge numbers of uncorrected errors on the 3.1 channel (currently 2 billion errors showing!). Can someone help with this please?

3.0 Downstream channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	331000000	6.8	40	QAM 256	25
2	211000000	3.6	39	QAM 256	10
3	219000000	3.1	39	QAM 256	11
4	227000000	2.8	39	QAM 256	12
5	235000000	2.9	39	QAM 256	13
6	243000000	3.1	39	QAM 256	14
7	251000000	3.1	39	QAM 256	15
8	259000000	2.9	39	QAM 256	16
9	267000000	3.2	40	QAM 256	17
10	275000000	4.1	40	QAM 256	18
11	283000000	4.8	40	QAM 256	19
12	291000000	5.5	40	QAM 256	20
13	299000000	5.8	40	QAM 256	21
14	307000000	6.1	40	QAM 256	22
15	315000000	6.2	40	QAM 256	23
16	323000000	6.5	40	QAM 256	24
17	339000000	7.3	40	QAM 256	26
18	347000000	7.6	41	QAM 256	27
19	355000000	8	41	QAM 256	28
20	363000000	8.8	41	QAM 256	29
21	371000000	9.7	41	QAM 256	30
22	379000000	10.3	41	QAM 256	31
23	387000000	10.3	41	QAM 256	32
24	395000000	10.1	41	QAM 256	33
25	403000000	10	41	QAM 256	34
26	411000000	10.1	41	QAM 256	35
27	419000000	9.7	41	QAM 256	36
28	427000000	9.3	41	QAM 256	37
29	435000000	8.5	41	QAM 256	38
30	443000000	7.4	41	QAM 256	39
31	451000000	5.9	40	QAM 256	40

3.0 Downstream channels

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

1	Locked	40	28	0
2	Locked	39	18	0
3	Locked	39	18	0
4	Locked	39	11	0
5	Locked	39	386	44
6	Locked	39	16	0
7	Locked	39	27	0
8	Locked	39	40	0
9	Locked	40	59	0
10	Locked	40	93	0
11	Locked	40	124	0
12	Locked	40	149	0
13	Locked	40	103	0
14	Locked	40	123	0
15	Locked	40	187	0
16	Locked	40	52	0
17	Locked	40	30	0
18	Locked	41	34	0
19	Locked	41	51	0
20	Locked	41	44	0
21	Locked	41	21	0
22	Locked	41	27	0
23	Locked	41	24	0
24	Locked	41	31	0
25	Locked	41	22	0
26	Locked	41	16	0
27	Locked	41	13	0
28	Locked	41	17	0
29	Locked	41	9	0
30	Locked	41	12	0
31	Locked	40	13	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

27

-17.4

835340381

1989194209

3.0 Upstream channels

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

0	49600000	45.3	5120	QAM 64	1
1	43100000	44.5	5120	QAM 64	2
2	36600000	43.5	5120	QAM 64	3
3	30100000	42.5	5120	QAM 64	4
4	23600000	41.3	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	5	0
3	ATDMA	0	0	7	0
4	ATDMA	0	0	6	0

3.1 Upstream channels

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

6

11

41.7

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

[Lee_R]

Hi @Mike14 thanks for posting and welcome back to our community.

Sorry to hear that you've been having ongoing issues with your connection. And sorry for any inconvenience this may be causing you. We've looked at our systems and we need to send a technician. I am going to send you a private message so we can confirm some details. Please keep an eye on your inbox in the top right of your screen.

Regards

Lee_R

[Lee_R]

Hi @Mike14, thanks for getting back to me privately. 
I have booked you in for the next available appointment. To view this please sign into My Virgin Media here. Once you log in scroll down to Orders & appointments then click on View your orders. 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 that someone over the age of 18 is at the property for the time the engineer is there. If the appointment is unsuitable or if anyone living at your property has tested positive for Coronavirus, has been asked to self-isolate or has flu-like symptoms then please reschedule the appointment on the same link. If you do miss the appointment for any reason, a £25 missed appointment charge will be applied to your account on the day of the appointment, so it is important to reschedule if needed. 
Do please let us know how the appointment goes. 
Take care.

Lee_R

[Mike14]

Hi Lee. Thanks very much for arranging the appointment for tomorrow. I'm hoping they can sort it.

[Mike14]

Hi

The technician fixed it today, so I'm very happy. 

There had apparently been a miscommunication, as he thought he was coming to fix an issue with my phone line! But he listened to my explanation, and could see some frequencies coming through at very low power. He checked and found the underground amplifier that I was connected to was faulty (which i had guessed after reading this forum, and you may also have expected), so he swapped me to a spare tap on an adjacent amplifier that works fine. He confirmed everything is now in spec and I can see that in the stats on the hub, so I'm expecting it will be much more reliable. 

Thanks for your help, I'm quite impressed with how efficiently it got fixed via this route. It was so much easier than trying to explain the issue to one of your operators on the phone. 

[Adduxi]

Yes, your power level on 3.1 was -17.4, so really low. Should be between -6 and +10.  However as for the Corrected Errors, this seems to be the case that several millions is the norm and doesn't cause any problems. It's the Uncorrectable errors that are the problem, and it looks like the amp was the cause.

[Mike14]

Yes, following the fix, power on 3.1 has gone from -17.4 to -0.3. And uncorrectable errors has gone from 100 million per hour to less than 50 per hour. 

[Matthew_ML]

Hey Mike14, thank you for reaching out and I am sorry to hear this.

I can see you are in PM with my colleague please do send them another message if you need to.