DOCSIS 3.1 channels - High number of Uncorrectables (Active Profile) and T4 timeouts

[alainchateau]

Good afternoon,

I've been on the 1 gig connection for about a year now. Recently I've seen some more inconsistent speed fluctuations throughout the day. I reset the router and within 24 hours I seem to be getting a small number of T4 timeouts and a high number of uncorrectables on the 3.1 channels. Is this normal and within the margin of what is acceptable? 

Thank you in advance for any help/comments. 

3.0 Downstream channels

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

25	331000000	1.599998	40.366287	QAM256	25
6	179000000	0.900002	40.366287	QAM256	6
7	187000000	0.900002	40.366287	QAM256	7
8	195000000	0.900002	38.983261	QAM256	8
9	203000000	1.000000	40.366287	QAM256	9
10	211000000	1.099998	40.366287	QAM256	10
11	219000000	1.099998	40.366287	QAM256	11
12	227000000	1.000000	40.366287	QAM256	12
13	235000000	0.900002	40.366287	QAM256	13
14	243000000	0.700001	40.366287	QAM256	14
15	251000000	0.700001	38.983261	QAM256	15
16	259000000	1.200001	40.366287	QAM256	16
17	267000000	1.000000	38.983261	QAM256	17
18	275000000	0.900002	38.983261	QAM256	18
19	283000000	1.500000	38.983261	QAM256	19
20	291000000	2.400002	38.983261	QAM256	20
21	299000000	2.900002	40.366287	QAM256	21
22	307000000	2.299999	40.366287	QAM256	22
23	315000000	1.900002	40.366287	QAM256	23
24	323000000	1.400002	38.983261	QAM256	24
26	339000000	1.900002	40.366287	QAM256	26
27	347000000	2.000000	40.366287	QAM256	27
28	355000000	1.799999	40.366287	QAM256	28
29	363000000	1.900002	40.366287	QAM256	29
30	371000000	2.000000	40.366287	QAM256	30
31	379000000	1.799999	40.366287	QAM256	31
32	387000000	1.500000	40.946209	QAM256	32
33	395000000	0.900002	38.605377	QAM256	33
34	403000000	0.400002	38.983261	QAM256	34
35	411000000	0.299999	38.983261	QAM256	35
36	419000000	0.400002	38.983261	QAM256	36

3.0 Downstream channels

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

25	Locked	40.366287	1	0
6	Locked	40.366287	1	0
7	Locked	40.366287	0	0
8	Locked	38.983261	0	0
9	Locked	40.366287	2	0
10	Locked	40.366287	0	0
11	Locked	40.366287	0	0
12	Locked	40.366287	0	0
13	Locked	40.366287	2	0
14	Locked	40.366287	1	0
15	Locked	38.983261	0	0
16	Locked	40.366287	0	0
17	Locked	38.983261	1	0
18	Locked	38.983261	0	0
19	Locked	38.983261	0	0
20	Locked	38.983261	0	0
21	Locked	40.366287	0	0
22	Locked	40.366287	0	0
23	Locked	40.366287	0	0
24	Locked	38.983261	0	0
26	Locked	40.366287	2	0
27	Locked	40.366287	1	0
28	Locked	40.366287	1	0
29	Locked	40.366287	0	0
30	Locked	40.366287	1	0
31	Locked	40.366287	0	0
32	Locked	40.946209	0	0
33	Locked	38.605377	0	0
34	Locked	38.983261	2	0
35	Locked	38.983261	0	0
36	Locked	38.983261	0	0

3.1 Downstream channels

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

159

96

4K

1880

QAM4096

759

3.1 Downstream channels

Channel ID Lock Status RxMER Data (dB) PLC Power (dBmV) Correcteds (Active Profile) Uncorrectables (Active Profile)

159

Locked

41

1.1

1956125730

8457

[alainchateau]

3.0 Upstream channels

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

1	36600000	51.020599	5120 KSym/sec	64QAM	11
2	23600000	49.270599	5120 KSym/sec	64QAM	13
3	30100000	50.020599	5120 KSym/sec	64QAM	12
4	43100000	51.020599	5120 KSym/sec	64QAM	10
5	49600000	51.770599	5120 KSym/sec	64QAM	9

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1	US_TYPE_STDMA	0	0	0	0
2	US_TYPE_STDMA	0	0	4	0
3	US_TYPE_STDMA	0	0	5	2
4	US_TYPE_STDMA	0	0	6	2
5	US_TYPE_STDMA	0	0	5	0

3.1 Upstream channels

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

14

10.0

47.0

2K

QAM8

3.1 Upstream channels

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

14

OFDMA

200

53.9

6

2

[Tudor]

Your upstream is struggling. Possibly a cable or cabinet problem, although I don’t think it’s a cable problem by your downstream levels. Possibly moving you to another tap on the street cabinet may fix the problem. Are you a long way from the street cabinet? In any case I think you will need a technician’s visit unless there is an area problem.

Check with Area faults on 0800 561 0061 If you have a VM landline 150 this goes down to post code level. You could also try the web page status, but this is not recommended as it only covers issues that affect a very large number of customers.

VM will not dispatch any technicians while an area fault exists.

If no area faults found:

Call Customer Services on 0345 454 1111/150 if you have a VM landline or wait two or three days for a VM staff member to get to your post.

[alainchateau]

• We're about 250m to the nearest roadside smaller cabinet type.
• No reported issues online or on the phone.

I'll sit it out for a forum member to pick up the post here and keep an eye on reported time outs the next week.

Thanks for commenting.

[alainchateau]

Update on upstream power levels and timeouts.

Also under downstream the uncorrectables has also climbed to over 34k. Not sure if this is considered normal.

3.1 Downstream channels

Channel ID Lock Status RxMER Data (dB) PLC Power (dBmV) Correcteds (Active Profile) Uncorrectables (Active Profile)

159

Locked

41

1.6

3637966014

34300

3.0 Upstream channels

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

1	36600000	50.020599	5120 KSym/sec	64QAM	11
2	23600000	48.770599	5120 KSym/sec	32QAM	13
3	30100000	49.520599	5120 KSym/sec	64QAM	12
4	43100000	50.520599	5120 KSym/sec	64QAM	10
5	49600000	51.270599	5120 KSym/sec	64QAM	9

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1	US_TYPE_STDMA	0	0	0	0
2	US_TYPE_STDMA	0	0	6	0
3	US_TYPE_STDMA	0	0	8	2
4	US_TYPE_STDMA	0	0	7	2
5	US_TYPE_STDMA	0	0	6	0

3.1 Upstream channels

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

14

10.0

46.2

2K

QAM8

3.1 Upstream channels

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

14

OFDMA

200

53.9

7

2

[Reece_MH]

Hi alainchateau,

Thanks for your post, and welcome back to our Community Forums.

I'm sorry to hear you're having some issues with your speeds. I've taken a look on our side, and can see your services are currently affected by a known issue - this may be the cause of the timeouts and uncorrectables. The details for the issue are:

Fault Type: SNR (Signal-To-Noise) - You might find that your Virgin Fibre, Voice and Virgin TV services are intermittent, with the picture freezing or disappearing now and then.
Fault Ref: F010371293
Estimated Fix Time: 10 JAN 2023 09:00

We're very sorry for any inconvenience this may cause in the meantime and rest assured, we're working on getting this resolved as soon as possible.

Thanks,
 

[alainchateau]

Thanks so much for the update.

Reassuring it's a known issue and is being worked on.

Kind regards 

[Martin_N]

You're welcome. 

^Martin

[alainchateau]

So it's passed the 10th Jan and I'm still having problems.

While playing a game last night I was dropping packets that made the game unplayable. I set up a broadband monitor and can see that I'm getting strange latency spikes and dropping packets. Can this please be investigated? 

[alainchateau]

Full days graph, The more considerable red packet loss is when I tried restarting the Virgin router, but alas still a problem.

So yeah, latency all over the place and packet loss. The good news is Truespeed is installing FTTP in the area, so looking forward to swapping to them for full 900mbps up/down come May. Ever since I've moved into this property and had 2 engineer visits I'm still back with this problem around latency and packet loss that keeps coming back. Poor service and connection for £100 pcm.