Constant dropouts: SYNC Timing Synchronization failure - Loss of Sync

[mmcw]

I joined VM a week ago (7th Oct) and for the first few days, everything was stable. However, I started noticing dropouts so setup a BQM to monitor connectivity. Throughout the day, there are spikes of 100% packet loss, and inspecting the network log always presents the following error: 'SYNC Timing Synchronization failure - Loss of Sync'.

I currently have the Hub 3 in modem mode, alongside my Netgear router. I've set it up this way since I joined as I am aware the Hub 3 isn't great, especially with regards to the distance it can cover. As I mentioned, the first few days were without issue.

I did a bit of research into the error log by going through this forum, and came across a few suggestions about power levels. After inspecting the downstream power levels, they were indeed high with the first few channels at 11dBmV. I had a spare 3dB from when I was with Virgin a few years back, so I attached that and the power levels dropped to 8dB. However, the dropouts still occur 😞

Can anyone advise further on what I can try to resolve this? (I have already triple checked connections and reset the router)

Link to live BQM: 

https://www.thinkbroadband.com/broadband/monitoring/quality/share/d80815847f5f4a4b398241e519daf0fd21893ad5

[mmcw]

Network Log

Time Priority Description

16/10/2022 10:13:7	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 10:13:7	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 10:13:6	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 10:13:6	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 10:13:5	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 10:13:5	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 10:13:4	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 09:56:38	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 09:49:56	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 09:49:56	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 09:49:55	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 09:49:55	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 08:53:19	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 08:53:19	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 08:52:58	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 06:50:25	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/10/2022 01:02:22	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

Downstream bonded channels

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

1	138750000	8	38	256 qam	1
2	146750000	8	38	256 qam	2
3	154750000	7.6	38	256 qam	3
4	162750000	7.5	38	256 qam	4
5	170750000	7.8	38	256 qam	5
6	178750000	7.5	38	256 qam	6
7	186750000	7.8	38	256 qam	7
8	194750000	7.4	38	256 qam	8
9	202750000	7	38	256 qam	9
10	210750000	7	38	256 qam	10
11	218750000	6.8	38	256 qam	11
12	226750000	6.8	38	256 qam	12
13	234750000	6.3	38	256 qam	13
14	242750000	6	38	256 qam	14
15	250750000	5.6	38	256 qam	15
16	258750000	5.6	38	256 qam	16
17	266750000	5.8	38	256 qam	17
18	274750000	6	38	256 qam	18
19	282750000	5.9	38	256 qam	19
20	290750000	6	38	256 qam	20
21	298750000	6	38	256 qam	21
22	306750000	6	38	256 qam	22
23	314750000	6	38	256 qam	23
24	322750000	6.3	38	256 qam	24

Downstream bonded channels

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

1	Locked	38.6	1719	5170
2	Locked	38.6	1668	8412
3	Locked	38.9	1614	8290
4	Locked	38.6	1557	8405
5	Locked	38.6	1539	8390
6	Locked	38.6	1410	7562
7	Locked	38.9	1413	7831
8	Locked	38.6	1437	7441
9	Locked	38.9	1341	7723
10	Locked	38.6	1281	7562
11	Locked	38.9	1200	7242
12	Locked	38.6	1230	7132
13	Locked	38.9	1264	6787
14	Locked	38.6	1230	6489
15	Locked	38.6	1257	6144
16	Locked	38.9	1208	6176
17	Locked	38.6	1298	5490
18	Locked	38.9	1237	5649
19	Locked	38.6	1241	5351
20	Locked	38.9	1200	5292
21	Locked	38.6	1188	5510
22	Locked	38.9	1204	5349
23	Locked	38.9	1186	5342
24	Locked	38.9	1161	5146

Upstream bonded channels

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

1	39400292	47.8	5120	64 qam	6
2	46200180	48.3	5120	64 qam	5
3	25799962	46.8	5120	64 qam	8
4	32600000	47.3	5120	64 qam	7

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

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

[Adduxi]

Far too many PostRS errors which would suggest noise on the circuit.  Check all connections are finger tight and not loose.  Reboot the Hub and keep an eye on the numbers.  If they rise quickly, it's a problem.  Other than this, you will need a VM technician to fix this,

If you wait here a day or two a VM Mod will pick this up.

[mmcw]

Yeah exactly, and those numbers are after a reboot late last night!

The coaxial cable provided by VM this time was a push fit rather than a screw type, all connections are secure however.

[Zach_R]

Hi @mmcw,

Thank you for your posts and welcome to our community forums. We're here to help.

I am so sorry to hear that you've been experiencing some problems with your connection recently. I can see that @Adduxi has offered some suggestions to help alleviate matters. Have these helped at all, or is the issue still ongoing for you today?

Thanks,
 

[mmcw]

Hi @Zach_R, yes the issue is still ongoing. BQM shows yesterday there were constant dropouts through the evening/night.

[mmcw]

Time Priority Description

19/10/2022 05:08:52	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2022 05:08:52	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2022 00:03:2	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2022 00:03:2	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 23:40:16	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:43:51	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:21:23	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:21:23	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:18:36	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:18:36	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:10:19	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:07:18	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:07:12	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:07:12	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:07:12	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:07:12	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:06:59	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:06:59	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:06:58	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2022 21:06:58	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

[mmcw]

Since I'm still having issues with a 3db attenuator attached with power levels at around 8dBmV, would I maybe require a greater attenuator to bring power levels down further maybe?

I've factory reset the router again, and still facing the same issues..

[Ashleigh_C]

Hi there @mmcw

I am so sorry to hear that you are still facing issues with your service!

I have taken a look and I can see that there are some issues with your set up that will require an engineer to come and take a look. 

I will pop you a PM now so we can arrange this, please keep an eye out for the purple envelope in the top right corner of your screen alerting you to a new message. 

Thank you. 

[mmcw]

Hi @Ashleigh_C, thank you but I have already called customer service myself to book an engineer. He/she will be here tomorrow - will update once the work is completed.