Slow downloads - since recent down time

[dragon-it]

After a bit of advice please before contacting VM, I'm more familiar with business networking and fibre and not dabbled into VM cable until had enough of the best we could get with VDSL.

VM 1gig service.  Has never been solid 1000 but has been pretty good (and better than the 50/13 could get with VDSL).  We moved the router recently to a new location using second cable the installer gave us but the speed continued to be the same at the new location and everything is securely connected.

We have had some slow(er) speed issues, my PC typically tops out around 250Mbit wired, and a mobile just now was getting 150Mbit tops while synced at 1100Mbit to the router and standing next to it.  I have had upto 550Mbits in the last week.  Virgin own speed test https://www.virginmedia.com/broadband/speed-test currently reports

Latency: 12.7 ms
Jitter: 1.90 ms
Download: 159 Mbps
Upload: 97.1 Mbps

Last week I think the issues started then later in the week we had around 24 hours without any service after a fault in the area affecting multiple people.

The router now sync 30 x DOCSIS 3.0 channels.  Most of those look reasonable but there is a section which have large error rates, low power and SNR

I didn't look before these issues at what was there to know if that is "normal" and the router works around the dodgy channels and still gets full speed?

The router originally connected with a 2m or so cable and had a 3dB attenuator connected next to it.  The replacement cable to move the router centrally is around 5-6m and originally still with the attenuator and currently trying without.

thanks

Steve

3.0 Downstream channels

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

1	419000000	3.8	37	QAM 256	36
2	139000000	6.6	31	QAM 256	1
3	147000000	6.6	31	QAM 256	2
4	155000000	5.1	30	QAM 256	3
5	163000000	2.6	29	QAM 256	4
6	171000000	1.2	29	QAM 256	5
7	179000000	-2	28	QAM 256	6
8	203000000	-2.6	29	QAM 256	9
9	227000000	3.3	34	QAM 256	12
10	235000000	4.3	36	QAM 256	13
11	259000000	5.6	36	QAM 256	16
12	267000000	5.7	36	QAM 256	17
13	275000000	5.8	36	QAM 256	18
14	283000000	5.2	36	QAM 256	19
15	291000000	3.7	35	QAM 256	20
16	299000000	3.9	34	QAM 256	21
17	307000000	3.4	33	QAM 256	22
18	315000000	3.2	36	QAM 256	23
19	323000000	3.6	36	QAM 256	24
20	331000000	3.2	36	QAM 256	25
21	339000000	3.7	36	QAM 256	26
22	347000000	4.4	36	QAM 256	27
23	355000000	4.7	37	QAM 256	28
24	363000000	4.3	37	QAM 256	29
25	371000000	4.1	36	QAM 256	30
26	379000000	4.2	36	QAM 256	31
27	387000000	4.2	36	QAM 256	32
28	395000000	4.3	36	QAM 256	33
29	403000000	4	37	QAM 256	34
30	411000000	3.6	37	QAM 256	35

3.0 Downstream channels

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

1	Locked	37	5743	2747
2	Locked	31	528445609	4448
3	Locked	31	1588041078	23295998
4	Locked	30	427309553	7062
5	Locked	29	2862024815	2468021
6	Locked	29	4124190092	312578574
7	Locked	28	4268586652	1070949178
8	Locked	29	3336012267	34452317
9	Locked	34	689644	6968
10	Locked	36	11804	3778
11	Locked	36	9186	3522
12	Locked	36	7713	3596
13	Locked	36	5518	3109
14	Locked	36	1255716585	177857
15	Locked	35	183471480	2494
16	Locked	34	14046	2147
17	Locked	33	59438	1771
18	Locked	36	14843	2213
19	Locked	36	11213	1880
20	Locked	36	18373	2238
21	Locked	36	14836	3426
22	Locked	36	16944	2062
23	Locked	37	5332	2553
24	Locked	37	5488	1869
25	Locked	36	5027	1378
26	Locked	36	6166	3210
27	Locked	36	5383	3155
28	Locked	36	9551	3521
29	Locked	37	4655	2960
30	Locked	37	5851	2768

3.1 Downstream channels

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

159

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)

159

Locked

39

2.7

884170157

72899

[legacy1]

downstream don't look to good maybe bad cable some where that noise on lower frequency bring down SnR 

[jbrennand]

Those stats are dreadful.  We need to see the Upstream data too though.

A VM person needs to take a look at the connection.  One will reply here soon.

In the meantime try this...

Switch the Hub off and unplug it from the mains supply for five minutes. Whilst it's off, do a quick check that all of your coax and ethernet cable connections are in nice and "finger" tight - at the Hub and wall box and also at any connectors etc. Ensure there are no “unterminated cable loose ends. Disconnect all the connections and reconnect to be sure. Also check that the internal wiring is ok with no kinking or chaffing. Then check that all looks good with the outside cabling and wall box (no “staples, etc.,) piercing the cables.

Then switch the Hub back on and leave ~5 minutes When all done, check back in the settings and ensure that the RS error counts and T3 errors have all reset to 0. Then check every hour or so to see if they start reappearing - they shouldn't. If they do (particularly the postRS and T3 ones) you have a problem (noise) that only a Tech visit will sort.   Also the down power levels  in channels 2-8 were all below the recommended minimum of 34dBmV - see if they are still low.
Also check the Upstream QAM’s are all at 64

[Ilyas_Y · Accepted solution]

Hi there @dragon-it Thanks for reaching out to us and a warm welcome to the Virgin Media Community forums. 👋🏼

I apologise to see the issues you are having with the broadband services as of recent. 😥
I've done some digging to see if there are any issues in the area. 🔍

As of yet - there is no SNR issue (signal to noise ratio issue), but after looking through, we can see there is a blip on the line which is causing an unstable connection for the time being.
I have raised this with my networks team on our end, they will monitor and clear off any drop outs on there, this can take up to 24 hours.

If after 24 hours the issues are still not resolved, please do reach back out to us as we will take this further. 🙂

Speak to you soon! 🔊

Kind regards,
Ilyas.

[dragon-it]

Thank you.  I have had a tech visit appointment appear on my phone as happening tomorrow (I didn't ask for it but this must have triggered it so good!).  I tried it again today with 3dB attenuator and was getting around 40Mbits, getting 500+ from ethernet connection at the moment.  Confirm the router totals were 0 but soon ramped up on same channels as before.  Both ends of internal cabling are connected normally.

thanks

Steve

[dragon-it]

After around 2 hours getting this on downstream (sorry didn't respond to earlier response from last week, found alerts going into spam filter).

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

1	Locked	37	46975	1557
2	Locked	31	27399077	1098
3	Locked	28	107288684	350390
4	Locked	30	10035844	26366
5	Locked	30	89820418	59649
6	Locked	29	113816542	2607215
7	Locked	29	109961830	11767564
8	Locked	29	116558496	142617
9	Locked	31	33923168	4083
10	Locked	35	857	49194
11	Locked	34	36709	57564
12	Locked	37	3757	54856
13	Locked	37	9855	49665
14	Locked	37	18269	42753
15	Locked	37	27286	34306
16	Locked	36	31869	29184
17	Locked	36	35283	27143
18	Locked	35	43669836	47595
19	Locked	36	616571	55960
20	Locked	36	13005	56011
21	Locked	34	18952	63950
22	Locked	37	24025	50381
23	Locked	37	32761	42837
24	Locked	36	38292	45667
25	Locked	38	46133	4145
26	Locked	38	48192	6184
27	Locked	37	42776	1391
28	Locked	36	51832	3185
29	Locked	37	45361	1366
30	Locked	37	49778	2465

.1 Downstream channels

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

159

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)

159

Locked

39

-19.1

118514838

6099

and upstream is solid, no errors.

3.0 Upstream channels

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

0	49600000	46	5120	QAM 64	9
1	43100000	46.3	5120	QAM 64	10
2	36600000	48.3	5120	QAM 64	11
3	30100000	51.3	5120	QAM 64	12
4	23600000	55	5120	QAM 64	13

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

0	ATDMA	0	2	1	1
1	ATDMA	0	2	0	0
2	ATDMA	0	2	0	0
3	ATDMA	0	2	0	0
4	ATDMA	0	2	0	0

3.1 Upstream channels

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

14

10

40.0

2K

QAM 256

3.1 Upstream channels

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

14

OFDMA

200

74000000

0

0

[dragon-it]

Thanks all for the advice there and the engineer that arrived sorted it out.  Couldn't find any errors or issues at our end externally or internally but his report was intermittent upload (which has actually been solid 100).

This has only been in about 6-8 months but he found a broken cable in the cabinet where the coax was half coming out of the plug and snapped the central wire so a poor termination originally and intermittent, or snagged when someone else in the box I guess.

Anyway after a couple of hours still all errors at 0 and everything nice and level, never seen that for several months.

So issue closed hopefully.

[Tom_W1]

Hi @dragon-it thanks for your post here in the Community although we're sorry to hear of the concerns you've raised here.

We're pleased to hear that since you've contributed here you've been able to get this sorted.

if you do need any further assistance please don't hesitate to let us know!
Many thanks