SYNC Timing Synchronization failure - Loss of Sync

[Doron]

My internet connection keeps dropping intermittently, sometimes for 30 seconds sometimes for as many as 5 minutes. It always comes back by itself but the outages obviously interfere with Zoom calls and such. In the network logs I can see many critical events:

Time Priority Description

13/07/2021 14:16:51	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 13:31:41	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 13:05:40	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 13:04:15	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 12:54:15	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 12:50:59	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 12:22:6	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 12:18:16	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:59:37	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:58:12	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:39:6	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:37:55	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:37:18	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:36:15	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 11:34:18	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 10:55:49	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 10:53:54	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 10:42:57	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
13/07/2021 10:41:14	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
12/07/2021 18:40:47	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

I've tried all the usual resolution techniques (restart the router, check cables are tight, etc) and none of them resolve the issue. Other similar forum posts suggest that an engineer visit is required to identify the issue. Any other suggestions or do I need to wait for someone from VM to book an engineer?

[lotharmat]

Post up the rest of the hub stats! - Someone should be able to see what the problem could be!

The log looks very bad!

Also, set up a 'Broadband Quality Monitor'. This will monitor the state of your connection and record any network dropouts etc - You can do this at ThinkBroadband (https://www.thinkbroadband.com/broadband/monitoring/quality)
Give it a while to gather data and then click 'Share Live graph' and paste the 'Direct Link' into the forum!

[Doron]

Downstream bonded channels

Channel	Frequency (Hz)	Power (dBmV)	SNR (dB)	Modulation	Channel ID
1	139000000	-1.5	36	256 qam	1
2	147000000	-1.9	36	256 qam	2
3	155000000	-2	36	256 qam	3
4	163000000	-2	36	256 qam	4
5	171000000	-1.7	36	256 qam	5
6	179000000	-2.2	36	256 qam	6
7	187000000	-1.9	36	256 qam	7
8	195000000	-2.5	37	256 qam	8
9	203000000	-3.2	36	256 qam	9
10	211000000	-3.7	36	256 qam	10
11	219000000	-4.2	36	256 qam	11
12	227000000	-5	36	256 qam	12
13	235000000	-5.2	36	256 qam	13
14	243000000	-7.4	36	256 qam	14
15	251000000	-6.4	36	256 qam	15
16	259000000	-4.9	36	256 qam	16
17	267000000	-4.9	36	256 qam	17
18	275000000	-4.4	36	256 qam	18
19	283000000	-3.7	36	256 qam	19
20	291000000	-3.2	37	256 qam	20
21	299000000	-2.9	37	256 qam	21
22	307000000	-2.7	37	256 qam	22
23	315000000	-2.7	37	256 qam	23
24	323000000	-2.2	37	256 qam	24

Downstream bonded channels

Channel	Locked Status	RxMER (dB)	Pre RS Errors	Post RS Errors
1	Locked	36.3	31891865	11402455
2	Locked	36.6	3793258	285975
3	Locked	36.6	606598	53631
4	Locked	36.6	1024113	85740
5	Locked	36.6	359106	23455
6	Locked	36.6	323408	18338
7	Locked	37.3	436288	19938
8	Locked	37.3	748687	64658
9	Locked	36.6	424897	29367
10	Locked	36.6	173960	2816
11	Locked	36.3	168714	2676
12	Locked	36.6	548338	19350
13	Locked	36.3	568548	24799
14	Locked	36.3	221608	4929
15	Locked	36.3	111338	1028
16	Locked	36.3	69749	976
17	Locked	36.6	40120	841
18	Locked	36.3	57755	913
19	Locked	36.6	17400	396
20	Locked	37.3	7659	318
21	Locked	37.3	3488	107
22	Locked	37.3	2727	212
23	Locked	37.6	3232	233
24	Locked	37.3	5893	98

[Doron]

Upstream bonded channels

Channel	Frequency (Hz)	Power (dBmV)	Symbol Rate (ksps)	Modulation	Channel ID
1	32600049	51	5120	64 qam	3
2	39400058	51	5120	64 qam	2
3	46199975	51	5120	64 qam	1
4	25799936	51	5120	64 qam	4

Upstream bonded channels

Channel	Channel Type	T1 Timeouts	T2 Timeouts	T3 Timeouts	T4 Timeouts
1	ATDMA	0	0	7	0
2	ATDMA	0	0	3	0
3	ATDMA	0	0	5	0
4	ATDMA	0	0	13	0

[Doron]

TB graph available at:

https://www.thinkbroadband.com/broadband/monitoring/quality/share/65b7abc4caad29ce1dfd0560e731ce7cc6014a58

[lotharmat]

Upstream is maxed out
Downstream is too low

VM Definitely need to send a tech!

[Akua_A]

Hi @Doron

Welcome to our community forums and thank you for your first posts.

Sorry to hear you have been experiencing ongoing intermittent issues. We can understand this is not ideal especially when working from home. I have just sent you a private message regarding this. Please look out for the purple envelope on the top right hand corner of the page and provide a response when you can.

Thanks,

[Doron]

Hi @Akua_A, thanks for your reply. I don't see anything from you in my inbox - are you sure it was sent?

[Akua_A]

Thank you for letting me know @Doron

How strange! I will send you another private message.

Please let me know if you are able to see it.

Thanks,

[Doron]

Thanks for your help identifying the problem @lotharmat. I want to understand how it is that you know that my broadband connection is 'very bad'? What about the numbers that you see in what I pasted identifies this? How do you know the upstream is maxed out and the downstream is too low? Do you know what 'normal' values for these metrics should be?