Frequent Packet Drops/Loss - SYNC Timing Syncronisation Failure?

[Milney]

I had posted in the gaming support, but felt that a more detailed post here is likely to get a better response.

For a considerable length of time - probably at least 9 months, if not more - I have been suffering from frequent but irregular packetloss on my VM Fibre connection.

It was first noticed as on Microsoft Teams/Zoom calls when working from home my colleagues would report that I would occassionally freeze up, even though I could still see and hear them. As this was the only symptom (that I had noticed) I chalked it up to a connection with Teams/Zoom rather than an ISP issue. However over the last few months I have noticed when using online applications (in particular games) which require a constant connection that I get a frequent but irregular dropout causing packetburst/packetloss and the associated impact on gameplay and service that you would expect.

At the end of January I set up a BQM to check, and the frequent spikes are clearly shown. I have done all the standard troubleshooting steps - rebooting the Hub, checking the cables, resetting and so on. However a quick comparison of my Network Log to some historic cases on the forum seem to indicate that this is an issue with VM itself.

Downstream bonded channels

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

1	387000000	1.5	40	256 qam	32
2	139000000	-2.2	38	256 qam	1
3	147000000	-2.4	38	256 qam	2
4	155000000	-2.4	38	256 qam	3
5	163000000	-2.5	38	256 qam	4
6	171000000	-2	38	256 qam	5
7	179000000	-1.7	38	256 qam	6
8	187000000	-1.2	38	256 qam	7
9	195000000	-1.4	40	256 qam	8
10	203000000	-1.5	40	256 qam	9
11	211000000	-1.4	40	256 qam	10
12	219000000	-1.4	38	256 qam	11
13	227000000	-1.5	38	256 qam	12
14	235000000	-1.4	40	256 qam	13
15	291000000	0.5	40	256 qam	20
16	299000000	1	40	256 qam	21
17	307000000	1.4	40	256 qam	22
18	315000000	1.5	40	256 qam	23
19	323000000	1.7	40	256 qam	24
20	347000000	1.9	40	256 qam	27
21	355000000	1.7	40	256 qam	28
22	363000000	1.4	40	256 qam	29
23	371000000	1.2	40	256 qam	30
24	379000000	1.5	40	256 qam	31

Downstream bonded channels

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

1	Locked	40.3	19805	195715
2	Locked	38.6	108947	8023
3	Locked	38.6	52769	822193
4	Locked	38.6	49273	8436
5	Locked	38.9	44176	13074
6	Locked	38.9	70334	16532
7	Locked	38.6	24687	14993
8	Locked	38.6	15787	15846
9	Locked	40.3	10755	18079
10	Locked	40.3	18843	15205
11	Locked	40.3	6822	16780
12	Locked	38.9	7184	14446
13	Locked	38.6	10854	14582
14	Locked	40.3	12308	15733
15	Locked	40.9	19231	15266
16	Locked	40.3	5665	16485
17	Locked	40.3	4833	17544
18	Locked	40.3	5159	19561
19	Locked	40.9	6166	20477
20	Locked	40.3	4690	16440
21	Locked	40.9	4065	17475
22	Locked	40.9	4659	16458
23	Locked	40.3	4634	18992
24	Locked	40.3	2663	63053

Upstream bonded channels

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

1	30100000	40.3	5120	64 qam	4
2	23600000	40.3	5120	64 qam	5
3	36600000	40.8	5120	64 qam	3
4	43100000	40.3	5120	64 qam	2
5	49600000	40.8	5120	64 qam	1

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1	ATDMA	0	0	2	0
2	ATDMA	0	0	1	0
3	ATDMA	0	0	6	0
4	ATDMA	0	0	4	0
5	ATDMA	0	0	4	0

[Milney]

I've been having issues with my Virgin Media fibre connection. At first, all I noticed was that occasionally during Microsoft Teams/Zoom calls whilst working from home, I would occasionally "drop" connection - though I could still see and hear other participants, my feed would freeze for them. 

Initially I shrugged this off as a quirk of those programs, as I was still receiving video streams. However, when gaming I noticed that I would get frequent (but irregular) packetburst and packetloss. This was intrusive, but also in some games causes autodisconnects even though the packetburst lasts for only a brief moment. As such this has made any sort of online gaming practically impossible. At the end of January I set up a Broadband Quality Monitor, and it shows these packetbursts very clearly.

The fact that they also happen in the small hours of the morning, although less frequently, indicates that this is likely an issue with the ISP rather than due to anything on my end as there is no usage during those times.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/f6e7219aa16706904a3e11d10b23dcc1d2a35e2b

 I've checked through all the standard checklists, checked physical cable connections, rebooted the router etc. but to no avail. Virgin seems to have a brick wall when trying to contact them to address this however.

[Milney]

Network Log

Time Priority Description

17/02/2024 23:02:28	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 22:52:49	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 22:43:11	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 20:05:52	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 19:26:12	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 18:46:19	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 16:42:17	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 10:00:24	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
17/02/2024 08:21:27	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 17:09:32	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 15:57:18	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 13:46:37	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 12:53:21	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 10:36:46	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 09:53:7	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 01:09:49	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/02/2024 01:08:47	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
15/02/2024 16:24:5	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
15/02/2024 15:12:4	notice	DHCP Renew - lease parameters tftp file-cmreg-vmdg505-bbt062-b.cm modified;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
15/02/2024 15:12:4	Error	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

[Milney]

BQM: 

https://www.thinkbroadband.com/broadband/monitoring/quality/share/0915288b112434c06630f6524a48049087b3d716-17-02-2024

[Sabrina_B]

Hi @Milney 👋.

Thanks for reaching out to us and welcome to the Community Forums. Apologies for the issues that you have been having with your internet. We can certainly assist you, we would need to bring you in for a private message to discuss this and resolve. 

Please look out for the envelope on the top right of your web browser or if you are using a mobile device, it will be located under your profile icon.
 

Thanks.
 

Sabrina