Virgin Media Community

[Adduxi]

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@toasty772 wrote:

Thanks for the input everyone, an engineer came and changed the hub to a Hub 3 and replaced the silver filter(?) that's just before the TV / broadband  cable splitter in the house to one which kept the levels at a more acceptable rate. All seemed good on the whole (apart from only 3 upstream bonded channels ?) Started cutting out the other day again so I rebooted the modem and noticed that there were 4 upstream bonded channels , lots of dropouts and low downstream power levels but the next day it seemed OK so will keep an eye on things.

Still getting a few "No Ranging Response received - T3 time-out" errors in the logs I notice.

If there's more issues I'll post the log outputs here again. Do I need to redact the MAC address from the log before posting ?

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Absolutely, you need to remove the MAC address. 🙂 

[toasty772]

Been cutting out loads today 😞

Looking at the logs, I'm guessing it's due to the downstream power levels being way too low ? I don't think they're this low when it's running OK. Is it normal for the power levels to fluctuate like this ?

Thanks for any pointers anyone's able to provide.....

_______

Downstream bonded channels
Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
1 298750000 -7.4 36 256 qam 21
2 170750000 -9.5 37 256 qam 5
3 178750000 -9 37 256 qam 6
4 186750000 -8.9 37 256 qam 7
5 194750000 -8.9 37 256 qam 8
6 202750000 -8.5 37 256 qam 9
7 210750000 -8.5 37 256 qam 10
8 218750000 -8.7 37 256 qam 11
9 226750000 -9.2 36 256 qam 12
10 234750000 -9.7 36 256 qam 13
11 242750000 -10 35 256 qam 14
12 250750000 -10 35 256 qam 15
13 258750000 -10 35 256 qam 16
14 266750000 -9.7 35 256 qam 17
15 274750000 -9.2 35 256 qam 18
16 282750000 -8.7 36 256 qam 19
17 290750000 -8.2 36 256 qam 20
18 306750000 -7 36 256 qam 22
19 314750000 -6.9 36 256 qam 23
20 322750000 -7 36 256 qam 24
21 402750000 -7.5 35 256 qam 25
22 410750000 -8 35 256 qam 26
23 418750000 -8 36 256 qam 27
24 426750000 -7.2 36 256 qam 28

Downstream bonded channels
Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
1 Locked 35.7 2041795 264188
2 Locked 37.3 5538698 240894
3 Locked 37.3 4964306 247523
4 Locked 37.6 4461520 255100
5 Locked 37.6 3913648 261911
6 Locked 37.3 3917483 309487
7 Locked 37.3 3896031 341049
8 Locked 36.6 4150390 362706
9 Locked 36.3 4405623 344505
10 Locked 36.3 4796884 359983
11 Locked 35.7 5018614 356948
12 Locked 35.7 4831304 343340
13 Locked 35.7 4479466 361756
14 Locked 35.5 4055682 361168
15 Locked 35.5 3367519 343728
16 Locked 35.7 2776289 354141
17 Locked 36.3 2350043 354978
18 Locked 36.3 1759845 339418
19 Locked 36.3 1634046 323955
20 Locked 36.3 1650109 321953
21 Locked 35.7 1940493 315405
22 Locked 35.7 1869964 306214
23 Locked 35.5 1527381 322140
24 Locked 35.5 1319562 324583

Upstream bonded channels
Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 25799995 4.225 5120 16 qam 4
2 32599682 4.325 5120 16 qam 3
3 46199764 4.55 5120 16 qam 1
4 39399863 4.45 5120 16 qam 2

Upstream bonded channels
Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
1 ATDMA 0 0 0 0
2 ATDMA 0 0 0 0
3 ATDMA 0 0 0 0
4 ATDMA 0 0 0 0

Network Log
Time Priority Description
30/06/2019 19:10:14 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:15 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:15 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:16 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:33 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:33 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:39 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:10:39 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:32:49 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:32:50 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:38:31 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:39:27 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:39:27 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 19:39:27 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 20:10:23 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 20:10:23 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 20:10:25 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 20:10:25 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 20:13:29 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
30/06/2019 20:13:29 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;

[jbrennand]

Yes - all your downstream levels are out of range
Downstream: no lower than -6dBmV and no higher than 10dBmV - Close to 0 is optimal.
Call it in for a technician to come out and get them right - lots of post RS errors on a new Hub may well indicate noise on the connection - reboot the Hub to reset them to 0 then check over the next few hours/days whether they are building back up.

[toasty772]

Thanks for the info, still pretty bad this morning so I have another engineer appt booked for Wednesday. Fingers crossed!

[toasty772]

Right, engineer came out and checked the levels and said the 'equaliser' the previous engineer fitted isn't needed, and possible something external happened to affect the power levels since his visit. He removed the equaliser and the levels looked much more healthy, however this morning I've still been getting lots of dropouts. When these happen, the modem logs mention :

Warning! RCS Partial Service, and

critical SYNC Timing Synchronization failure - Loss of Sync

Any ideas what can be done, I'm getting constantly disconnected from online services and it's driving me to despair!

Downstream bonded channels
Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
1 298750000 -1.7 36 256 qam 21
2 138750000 -3.5 38 256 qam 1
3 146750000 -3 38 256 qam 2
4 154750000 -3.5 38 256 qam 3
5 162750000 -3.5 38 256 qam 4
6 170750000 -2.7 38 256 qam 5
7 178750000 -2.2 38 256 qam 6
8 186750000 -2.2 38 256 qam 7
9 194750000 -2 38 256 qam 8
10 202750000 -1.9 38 256 qam 9
11 210750000 -2 37 256 qam 10
12 218750000 -2.4 38 256 qam 11
13 226750000 -2.7 37 256 qam 12
14 234750000 -3.5 37 256 qam 13
15 242750000 -3.9 36 256 qam 14
16 250750000 -3.9 36 256 qam 15
17 258750000 -4 36 256 qam 16
18 266750000 -3.7 36 256 qam 17
19 274750000 -3.4 36 256 qam 18
20 282750000 -2.9 36 256 qam 19
21 290750000 -2.5 36 256 qam 20
22 306750000 -1.5 36 256 qam 22
23 314750000 -1.4 36 256 qam 23
24 322750000 -1.7 36 256 qam 24

Downstream bonded channels
Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
1 Locked 36.3 5088288 324463
2 Locked 38.6 24499736 256616
3 Locked 38.6 20782444 296045
4 Locked 38.6 21183457 323578
5 Locked 38.6 22338064 394973
6 Locked 38.6 16751139 427921
7 Locked 38.6 13239385 375848
8 Locked 38.9 12376688 364021
9 Locked 38.6 11263431 409941
10 Locked 38.6 10496484 428428
11 Locked 38.6 9856023 400299
12 Locked 37.6 10280012 447902
13 Locked 37.6 10464982 433784
14 Locked 37.3 11906674 417980
15 Locked 36.3 12368880 415899
16 Locked 36.3 11849433 425940
17 Locked 36.3 11092896 410338
18 Locked 36.6 9982751 428203
19 Locked 36.3 8346415 419976
20 Locked 36.6 6914383 418613
21 Locked 36.6 5866387 407683
22 Locked 36.6 4426196 408297
23 Locked 36.3 4134255 415677
24 Locked 36.6 4185939 390123

Upstream bonded channels
Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 25799673 4.15 5120 16 qam 4
2 32600092 4.275 5120 16 qam 3
3 46199902 4.525 5120 16 qam 1
4 39400195 4.375 5120 16 qam 2

Upstream bonded channels
Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
1 ATDMA 0 0 0 0
2 ATDMA 0 0 0 0
3 ATDMA 0 0 0 0
4 ATDMA 0 0 0 0

Network Log
Time Priority Description
03/07/2019 08:52:45 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:52:45 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:53:29 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:53:29 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:57:49 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:57:49 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:59:33 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 08:59:33 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:14:35 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:14:59 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:16:47 critical No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:27:17 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:55:55 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:55:55 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:59:4 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 09:59:4 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 10:00:16 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 10:00:16 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 10:00:41 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;
03/07/2019 10:00:41 Warning! RCS Partial Service;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:yy;CM-QOS=1.1;CM-VER=3.0;

[toasty772]

Now the power has shot up and the dropouts are just as bad. God knows what's going on.

Downstream bonded channels

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

1	298750000	12.9	36	256 qam	21
2	138750000	14	38	256 qam	1
3	146750000	14.1	38	256 qam	2
4	154750000	13.4	38	256 qam	3
5	162750000	13.6	38	256 qam	4
6	170750000	14.1	38	256 qam	5
7	178750000	14.4	38	256 qam	6
8	186750000	14.3	38	256 qam	7
9	194750000	14.3	38	256 qam	8
10	202750000	14.3	37	256 qam	9
11	210750000	14	37	256 qam	10
12	218750000	13.5	37	256 qam	11
13	226750000	12.9	37	256 qam	12
14	234750000	12.1	36	256 qam	13
15	242750000	11.5	36	256 qam	14
16	250750000	11.5	36	256 qam	15
17	258750000	11.1	36	256 qam	16
18	266750000	11.4	36	256 qam	17
19	274750000	11.5	36	256 qam	18
20	282750000	12	36	256 qam	19
21	290750000	12.3	36	256 qam	20
22	306750000	12.9	36	256 qam	22
23	314750000	13	36	256 qam	23
24	322750000	12.6	36	256 qam	24

[toasty772]

While the power levels went up the connection seemed to settle down eventually, started dropping again later this afternoon and I see the power levels have gone down again. the BQM graph looks interesting as well during this time (see below).

Absolutely nothing internal in the house would have affected the power levels, so I'm at a loss why they're fluctuating so much...

Downstream bonded channels

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

1	298750000	-2.2	36	256 qam	21
2	138750000	-3.7	38	256 qam	1
3	146750000	-3.7	38	256 qam	2
4	154750000	-3.9	38	256 qam	3
5	162750000	-3.2	38	256 qam	4
6	170750000	-2.7	38	256 qam	5
7	178750000	-2.5	38	256 qam	6
8	186750000	-2.5	38	256 qam	7
9	194750000	-2.4	38	256 qam	8
10	202750000	-2.2	38	256 qam	9
11	210750000	-2.4	38	256 qam	10
12	218750000	-2.7	38	256 qam	11
13	226750000	-3.2	37	256 qam	12
14	234750000	-3.9	37	256 qam	13
15	242750000	-4.4	37	256 qam	14
16	250750000	-4.2	37	256 qam	15
17	258750000	-4.2	36	256 qam	16
18	266750000	-4	36	256 qam	17
19	274750000	-3.7	36	256 qam	18
20	282750000	-3.2	36	256 qam	19
21	290750000	-3	37	256 qam	20
22	306750000	-2	37	256 qam	22
23	314750000	-1.9	36	256 qam	23
24	322750000	-2	36	256 qam	24

[jem101]

OK how about this as a possible working hypothesis?

Tell me, did the engineer(s) check any of the connections outside of your house, and, more importantly, did he check the street cabinet?

Suppose that what you have is a bad or loose connection somewhere between you and the cabinet. When the connection is good, you are getting the full power delivered to the hub, but a passing vehicle shakes the cabinet a bit and the connection loosens, down goes the power level, up goes the error rate and you have a problem.

The original installer puts you on a tab in the cabinet which gives a good upstream power level but the downstream is a bit too high, so he fits a forward part attenuator to the line to reduce this.

All is well until the connection degrades in the cabinet (bit of an assumption but seems fair enough). With the attenuator in place, the power is now too low and you have problems.

Now the second engineer turns up, measures that the power levels are too low and decides to put the attenuator - all fair enough, until the connection gets shaken up again and makes a good contact. Without the attenuator the power levels are now way too high, it overdrives the circuitry in the hub and again introduces all the errors.

Rinse and repeat.

Anyhow, like I said, but if a shot in the dark but does explain what you are seeing. You’ll still need another visit unfortunately to check the levels and connections from the cab back.

John

[toasty772]

Thanks for the suggestion John, does indeed sound like a viable explanation as to what could potentially be causing these fluctuations, I'm 99% certain it's nothing internal within the house.

When the power levels shot up, the connection did in fact settle down for a while, then went again later on (with a corresponding drop in power). You can see from the graph when this was !! Someone else with a similar problem said their external cable was reinstalled  following a visit which seems to have resolved the issue, maybe I need this too ? Will see what VM come back with....

[toasty772]

Could someone from support drop me a PM on this please ? thanks.