SYNC Timing Synchronization failure - High Post RS Errors on Downstream

[sduffield]

Over the last few weeks, I have been suffering from intermittent broadband dropouts; some lasting a 20 seconds, whilst others lasting 5 minutes.

Checking the Hub logs, I can see several errors relating to SYNC Timing Synchronization failures and high post RS errors. Rebooting the hub resolves the issue for a few days, however the issue returns. 

Virgin Media - would you be able to review the logs to ascertain the root cause?

Network Log
Time	Priority	Description
30/10/2024 15:55	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/10/2024 15:55	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/10/2024 15:55	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/10/2024 15:55	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
27/10/2024 19:44	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
27/10/2024 18:13	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
24/10/2024 08:49	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
24/10/2024 07:13	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
23/10/2024 11:05	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
21/10/2024 12:06	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 23:41	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 10:48	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 07:35	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 07:20	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 07:08	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 07:07	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 06:35	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
19/10/2024 03:06	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2024 22:10	Warning!	Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
18/10/2024 22:09	Warning!	RCS Partial Service;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	139000000	8.3	40	256 qam	1
2	147000000	8.5	38	256 qam	2
3	155000000	8	40	256 qam	3
4	163000000	7.6	40	256 qam	4
5	171000000	7.4	40	256 qam	5
6	179000000	6.8	40	256 qam	6
7	187000000	6.8	38	256 qam	7
8	195000000	6.3	40	256 qam	8
9	203000000	6	40	256 qam	9
10	403000000	1.7	40	256 qam	34
11	411000000	1.7	38	256 qam	35
12	419000000	1.5	40	256 qam	36
13	427000000	1.7	40	256 qam	37
14	435000000	1.5	40	256 qam	38
15	443000000	1.2	38	256 qam	39
16	451000000	1	40	256 qam	40
17	459000000	1	40	256 qam	41
18	467000000	0.7	38	256 qam	42
19	475000000	1	40	256 qam	43
20	483000000	0.9	38	256 qam	44
21	491000000	1	40	256 qam	45
22	499000000	1	40	256 qam	46
23	507000000	1	40	256 qam	47
24	515000000	1	40	256 qam	48
Downstream bonded channels
Channel	Locked Status	RxMER (dB)	Pre RS Errors	Post RS Errors
1	Locked	40.3	252	1389
2	Locked	38.9	342	1499
3	Locked	40.3	467	1937
4	Locked	40.9	350	1924
5	Locked	40.3	349	1458
6	Locked	40.3	683	1078
7	Locked	38.6	263	1585
8	Locked	40.3	622	1763
9	Locked	40.3	742	1819
10	Locked	40.3	7645	1622
11	Locked	38.9	7752	1385
12	Locked	40.3	7745	1570
13	Locked	40.9	6460	1707
14	Locked	40.3	6721	1035
15	Locked	38.9	4216	1146
16	Locked	40.3	3666	909
17	Locked	40.3	4448	968
18	Locked	38.6	4919	1010
19	Locked	40.9	4045	933
20	Locked	38.9	6952	1339
21	Locked	40.3	7047	1181
22	Locked	40.3	7446	1206
23	Locked	40.3	7671	1208
24	Locked	40.3	7078	1110
Upstream bonded channels
Channel	Frequency (Hz)	Power (dBmV)	Symbol Rate (ksps)	Modulation	Channel ID
1	23600015	46.5	5120	64 qam	9
2	36600000	47	5120	64 qam	3
3	30100000	46.8	5120	64 qam	4
4	49600018	47	5120	64 qam	1
5	43099995	47	5120	64 qam	2
Upstream bonded channels
Channel	Channel Type	T1 Timeouts	T2 Timeouts	T3 Timeouts	T4 Timeouts
1	ATDMA	0	0	2	0
2	ATDMA	0	0	3	0
3	ATDMA	0	0	2	0
4	ATDMA	0	0	1	0
5	ATDMA	0	0	2	0

[sduffield]

Today's Hub stats

[Ayisha_B]

Hi @sduffield 👋

Welcome back to our Community Forums and thanks for your post.

I am sorry to hear you are experiencing some issues with your service.

I've had a look at our systems and have identified an issue with your power levels. 

Will pop you a PM 📩 now so we can get an engineer visit booked for you.

Hope to hear from you soon.

[sduffield]

PM sent 

[Ayisha_B]

Thanks for confirming the requested details via PM @sduffield 

I've booked an engineer for you to come out and have a look into the issue with the power levels. You can find confirmation of the visit via your👉 online account.

Let me know if there are any problems with the date or time and I can look to reschedule this for you. In regards to the appointment there are some details you need to know about. There will be no charge for this visit unless:

•The engineer diagnoses the faults as not being caused by our network/equipment 
•The engineer discovers that the fault or problem relates to your equipment
•The engineer discovers that the fault or problem relates to any system that we are not responsible for

The engineer 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 there is someone over the age of 18 present at the time of the visit. If you need to change or cancel your appointment you can also do this online or via the MyVM app by 4pm the day before the appointment.

If you do miss an agreed appointment for any reason, a £25 missed appointment charge will be applied to your account on the day of the appointment.

Let us know how the visit goes! 🙂

[sduffield]

Thank you. Have seen the appointment appear in the app so thank you once again.