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SYNC Timing Synchronization failure - Loss of Sync - yes me too!

el_flandro
Joining in

We are on Volt M350 Fibre Broadband and get really good speeds most of the time. We don't use the wifi on the hub (we have disabled it), instead we have a tp-link Deco S4 mesh wifi system that makes sure we get great coverage throughout the house. However, just recently we have been experiencing occasional network dropout for a few seconds at a time - just long enough to ruin a Teams call for work!

Looking at the network log has shown me it's a SYNC Timing Synchronization failure.Like others, I have found that rebooting the router works for a while, but the problems return.

I've seen a few other people with this problem on the forum and the answer seems to be to share the relevant data here and wait for the Forum Team to pick up on it 🙂 However, all support and advice is welcome.

So here we go:

Network Log

Time Priority Description

04/08/2023 16:28:8noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 16:12:41Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 16:11:2noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 16:10:30criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 15:08:10Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 15:08:10Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:50:44Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:50:42Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:46:56Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:46:52Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:46:39Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:46:38Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:44:30Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:44:12Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:13:45Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 14:13:26criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 12:40:28Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 12:40:28criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 12:39:38Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
04/08/2023 12:39:38criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

 

5 REPLIES 5

el_flandro
Joining in

Downstream bonded channels

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

1139000000-5.737256 qam1
2147000000-6.436256 qam2
3155000000-5.936256 qam3
4163000000-5.237256 qam4
5171000000-537256 qam5
6179000000-538256 qam6
7187000000-4.538256 qam7
8195000000-4.438256 qam8
9203000000-3.938256 qam9
10211000000-3.737256 qam10
11219000000-3.531256 qam11
12227000000-3.732256 qam12
13235000000-4.738256 qam13
14243000000-4.538256 qam14
15251000000-4.738256 qam15
16259000000-4.438256 qam16
17267000000-2.738256 qam17
18275000000-2.938256 qam18
19283000000-1.540256 qam19
20291000000-238256 qam20
21299000000-1.538256 qam21
22307000000-1.738256 qam22
23315000000-2.538256 qam23
24323000000-1.238256 qam24



Downstream bonded channels

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

1Locked37.364430478172332
2Locked36.39893829126335
3Locked36.639282385354398
4Locked37.620914206929806
5Locked37.621062420028
6Locked38.6177659821727
7Locked38.610462026480
8Locked38.914117115885
9Locked38.612370712796
10Locked37.313169111701
11Locked31.31327614791-1721974570
12Locked32.6914468092086005
13Locked38.69418512693
14Locked38.68543712023
15Locked38.97847111584
16Locked38.67983610849
17Locked38.6673848841
18Locked38.9593358932
19Locked40.3350566270
20Locked38.9256307580
21Locked38.9360629043
22Locked38.9430338387
23Locked38.9426807482
24Locked38.9329896543

Upstream bonded channels

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

12359995153.5512064 qam5
23009998553.8512064 qam4



Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1ATDMA0010
2ATDMA0040

316f0314ea5fabe208d08aac6135bc9fe169c2b1-04-08-2023.png

Hi @el_flandro 

Thanks for posting and welcome to the community.

I am sorry to hear of the broadband issues you're having. I have done a system check today and some of your downstream channels are out of spec, plus you have only got two upstream channels showing, when should have four.

This will need a technician visit, so I shall PM you now to arrange this.

Best wishes.

John_GS
Forum Team


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el_flandro
Joining in

Thanks again for your help John. A brilliant VM engineer called Sam visited today and quickly narrowed the problem down to the cable outside the house. She replaced it and got everything up and running again - even fixed an issue I hadn't spotted with the TV as well. Great service.

Joseph_B
Forum Team (Retired)
Forum Team (Retired)

Hey @el_flandro,

Great to hear the appointment went well and they were able to fix everything up for you, if you do have any future issues or questions, do let us know and we can look into it for you.

Joe