Intermittent "SYNC Timing Synchronization failure - Loss of Sync;" - how to get engineer to come?

[gharkness]

This community is really useful - thanks all.

I've got the same issue that many have reported previously where internet connectivity drops out intermittently, with network logs like this:

14/02/2022 15:13:6	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 15:12:58	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

I can provide other data if that helps but, from reading other posts here, it feels like I need to get an engineer to come.

Unfortunately, I can't even get through to speak to a real person in Customer Services.  The automated systems just seem to test my connectivity - which is 99/100 _working_ - and they then direct me towards instructions for fixing my internal network, which is categorically not faulty 🙂

Any ideas how I can navigate VM Customer Services?

[g0akc]

set up a BQM and post the hub status in full here - it will provide more evidence

[gharkness]

Thanks, I created a BQM here.

[gharkness]

Thanks, I created a BQM here.

[gharkness]

Here are the logs:

Item Status Comments

Acquired Downstream Channel (Hz)	291000000	Locked
Ranged Upstream Channel (Hz)	53699991	Locked
Provisioning State	Online

[gharkness]

Downstream bonded channels

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

1	291000000	1.4	38	256 qam	20
2	139000000	3	38	256 qam	1
3	147000000	2.9	38	256 qam	2
4	155000000	2.7	38	256 qam	3
5	163000000	2.5	38	256 qam	4
6	171000000	2.2	38	256 qam	5
7	179000000	1.9	38	256 qam	6
8	187000000	1.9	38	256 qam	7
9	195000000	1.7	38	256 qam	8
10	203000000	1.4	38	256 qam	9
11	211000000	1	38	256 qam	10
12	219000000	0.7	38	256 qam	11
13	227000000	0.5	37	256 qam	12
14	235000000	0.2	37	256 qam	13
15	243000000	0	37	256 qam	14
16	251000000	-0.2	37	256 qam	15
17	259000000	-0.4	37	256 qam	16
18	267000000	0	37	256 qam	17
19	275000000	0.4	38	256 qam	18
20	283000000	1	38	256 qam	19
21	299000000	1.7	38	256 qam	21
22	307000000	1.7	38	256 qam	22
23	315000000	1.5	38	256 qam	23
24	323000000	1.5	38	256 qam	24

Downstream bonded channels

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

1	Locked	38.9	141193	8879
2	Locked	38.6	10170	6252
3	Locked	38.6	24955	8045
4	Locked	38.6	66658	10016
5	Locked	38.9	76593	9363
6	Locked	38.6	48631	7627
7	Locked	38.6	30016	6695
8	Locked	38.6	31224	6437
9	Locked	38.6	42814	7173
10	Locked	38.6	53778	7814
11	Locked	38.6	48960	6824
12	Locked	38.6	50167	6536
13	Locked	37.6	139472	7450
14	Locked	37.6	310406	8793
15	Locked	37.6	399798	9134
16	Locked	37.6	188499	8260
17	Locked	37.6	77308	6599
18	Locked	37.3	58909	6027
19	Locked	38.6	109264	7037
20	Locked	38.6	209715	8288
21	Locked	38.9	53273	7607
22	Locked	38.9	18958	6072
23	Locked	38.6	30452	6211
24	Locked	38.6	106166	8617

[gharkness]

Upstream bonded channels

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

1	53699991	45	5120	64 qam	2
2	32600002	43	5120	64 qam	5
3	39400009	43.5	5120	64 qam	4
4	46200004	43.5	5120	64 qam	3

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

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

General Configuration

Network access	Allowed
Maximum Number of CPEs	1
Baseline Privacy	Enabled
DOCSIS Mode	Docsis30
Config file	A,.iyewrkldJKDHSUBsgvca69

Primary Downstream Service Flow

SFID	354
Max Traffic Rate	690000278
Max Traffic Burst	42600
Min Traffic Rate	0

Primary Upstream Service Flow

SFID	353
Max Traffic Rate	44000278
Max Traffic Burst	42600
Min Traffic Rate	0
Max Concatenated Burst	42600
Scheduling Type	BestEffort

[gharkness]

Network Log

Time Priority Description

14/02/2022 15:13:6	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 15:12:58	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 15:12:19	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:54:9	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:48:23	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:48:16	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:46:43	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:43:49	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:43:45	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:43:38	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:41:51	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:41:51	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:34:8	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:34:8	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:33:59	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:33:59	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:12:46	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:12:46	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:12:26	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
14/02/2022 14:12:26	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

[gharkness]

Hmmm - the BQM shows that it's down constantly - which isn't true.

I wonder if my router (behind the Virgin Hub in modem mode) is configured not responding to pings?

Here's a graph of outgoing pings for the last three hours:

Five periods where pings got longer, and two complete dropouts.  The times correlate with records in the modem's network log.

[gharkness]

And filling in some more dropouts as the day has gone on 😞

Green is ping time - red is where there has been 10 consecutive packets lost.