Virgin Media Community

[TheWhiteZombie]

Hi, I've been having a read around the forum and believe I am also experiencing issues that others have reported previously with internet connectivity drop outs, reviewing the SuperHub 3 logs I can see errors referencing SYNC Timing Synchronization failure - Loss of Sync.

This affects devices which are connected via WiFi and ethernet, all devices affected at the same time. I have tried the following in my troubleshooting:

• a full reboot of the router
• changed the ethernet cable used on my main PC
• Ensured the coax cables are tightened as hard as I can
• Checked the cabling outside my property and it seems fine
• Running continous pings using PingInfoView to local router, Google DNS and Virgin DNS shows intermittent dropouts for the Google DNS and Virgin DNS during which I experience connectivity issues

I have setup a BQM monitor which you can view here:

https://www.thinkbroadband.com/broadband/monitoring/quality/share/62a4438e332c5fd56fb143755ade18bfe0891a04

Can anyone offer any suggestions? I have seen others advise that they have required an engineer to attend to resolve.

Thanks, Mick.

Here are some of the logs which I have taken from my router:

Time	Priority	Description
05/03/23 02:43	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:43	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:43	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:33	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:33	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:33	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:29	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:27	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:27	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:23	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:23	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:02	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:02	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:01	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:01	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

Channel	Locked Status	RxMER (dB)	Pre RS Errors	Post RS Errors
1	Locked	37.6	2717442	768435
2	Locked	37.6	1502216	540990
3	Locked	37.3	132211834	909944
4	Locked	37.6	1483745	587299
5	Locked	37.6	556698	263258
6	Locked	37.3	152970	66988
7	Locked	37.6	306351	226813
8	Locked	37.6	686845	361003
9	Locked	37.6	371668	143904
10	Locked	37.6	255890	102713
11	Locked	37.3	457657	166126
12	Locked	37.6	275228	76103
13	Locked	37.6	248479	65887
14	Locked	37.6	149334	29063
15	Locked	37.3	110943	28226
16	Locked	37.3	142647	33820
17	Locked	37.3	121920	25651
18	Locked	37.3	232881	55624
19	Locked	37.3	199072	35997
20	Locked	36.6	263681	46208
21	Locked	36.6	180473	30054
22	Locked	36.6	94994	13245
23	Locked	36.6	88676	11007
24	Locked	36.3	56778	5090

[TheWhiteZombie]

Hi, I have seen others post similar issues previously so hopefully someone may be able to help. I have a SuperHub 3 and I am experiencing intermittent internet connectivity issues where I see high latency and network dropouts which affects all devices on my home network, it affects both wired and wireless connections.

It seems to happen a couple of times per hour on average and is very noticeable when streaming or playing an online game.

Here are some things I have tried for troubleshooting:

• Changed to a new ethernet cable on my main PC
• Rebooted the router
• Checked to ensure the coax cables are as tight as can be by hand
• Checked the outside cabling with no visual issues
• Run continuous pings to Google and Virgin DNS servers and when I experience the intermittent issues it coincides with ping dropouts. Note - pinging local router is fine.

I have also setup a BQM which can be viewed here:

https://www.thinkbroadband.com/broadband/monitoring/quality/share/62a4438e332c5fd56fb143755ade18bfe0...

From reading some previous forum posts it seems an engineer has had to attend to resolve. Just wondering if anyone can help me out, or if theres any more troubleshooting I can do from my side?

Thanks, Mick

Here are some logs from my SuperHub3 :

Time	Priority	Description
05/03/23 04:46	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 04:46	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 03:30	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 03:30	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 03:30	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:43	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:43	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:43	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:37	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:33	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:33	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:33	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:29	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:27	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:27	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:23	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:23	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:02	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:02	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:01	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/03/23 02:01	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

Channel	Locked Status	RxMER (dB)	Pre RS Errors	Post RS Errors
1	Locked	37.6	2718080	770287
2	Locked	37.6	1502719	542842
3	Locked	37.6	132212600	911571
4	Locked	37.6	1484562	588594
5	Locked	37.3	557469	263889
6	Locked	37.3	153406	67163
7	Locked	37.6	306750	227577
8	Locked	37.3	687523	361988
9	Locked	37.3	372251	144310
10	Locked	37.3	256408	102989
11	Locked	37.6	458279	166513
12	Locked	37.6	275804	76315
13	Locked	37.3	249000	66058
14	Locked	37.6	149720	29195
15	Locked	37.3	111217	28344
16	Locked	37.3	143014	33907
17	Locked	37.6	122246	25744
18	Locked	37.3	233330	55782
19	Locked	37.3	199530	36106
20	Locked	36.6	264215	46355
21	Locked	36.6	180931	30149
22	Locked	36.6	95296	13293
23	Locked	36.3	88970	11043
24	Locked	36.6	56998	5102

[Anonymous]

High Post RS error counts and erratic BQM. 

Check for local faults on 0800 561 0061. 

Also post your upstream and downstream power levels. 

[TheWhiteZombie]

Thanks @Cardiffman281, please see the data from the upstream and downstream tabs on the Router status window:

Downstream bonded channels
Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
1 139000000 2 37 256 qam 1
2 147000000 1.5 37 256 qam 2
3 155000000 0.7 37 256 qam 3
4 163000000 0.7 37 256 qam 4
5 171000000 0.2 37 256 qam 5
6 179000000 0.2 37 256 qam 6
7 187000000 0.2 37 256 qam 7
8 195000000 0 37 256 qam 8
9 203000000 0 37 256 qam 9
10 211000000 0 37 256 qam 10
11 219000000 0 37 256 qam 11
12 227000000 -0.5 37 256 qam 12
13 235000000 -0.5 37 256 qam 13
14 243000000 -1.2 37 256 qam 14
15 251000000 -2.4 37 256 qam 15
16 259000000 -3.2 37 256 qam 16
17 267000000 -1.7 37 256 qam 17
18 275000000 -1.4 37 256 qam 18
19 283000000 -1 37 256 qam 19
20 291000000 -1.2 36 256 qam 20
21 299000000 -0.7 36 256 qam 21
22 307000000 -1.2 36 256 qam 22
23 315000000 -1.2 36 256 qam 23
24 323000000 -1.5 36 256 qam 24


Downstream bonded channels
Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
1 Locked 37.6 3070729 864319
2 Locked 37.6 1556280 625297
3 Locked 37.6 132282643 1005826
4 Locked 37.3 1544853 664549
5 Locked 37.3 611631 308986
6 Locked 37.3 181581 82264
7 Locked 37.6 337532 265171
8 Locked 37.6 737964 410141
9 Locked 37.6 414422 172282
10 Locked 37.3 291551 123673
11 Locked 37.6 503877 196005
12 Locked 37.3 314924 96319
13 Locked 37.6 284114 82758
14 Locked 37.6 178903 39096
15 Locked 37.3 133277 35453
16 Locked 37.3 167725 42800
17 Locked 37.3 145885 33390
18 Locked 37.3 266082 69181
19 Locked 37.3 230541 47422
20 Locked 36.3 301952 60935
21 Locked 36.6 214570 39641
22 Locked 36.6 118665 17147
23 Locked 36.3 111531 14832
24 Locked 36.3 72895 6737

Upstream bonded channels
Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 23600000 50.3 5120 64 qam 11
2 49599981 51 5120 64 qam 7
3 30100000 50.5 5120 64 qam 10
4 36600000 51 5120 64 qam 9
5 43099961 51 5120 64 qam 8
Upstream bonded channels
Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
1 ATDMA 0 0 1 0
2 ATDMA 0 0 0 0
3 ATDMA 0 0 0 0
4 ATDMA 0 0 2 0
5 ATDMA 0 0 0 0

[Anonymous]

Thanks. Downstream power levels have a wider range than usual and upstream power levels are too high. 

If there are no local faults on 0800 561 0061 then call it in as a fault. 

Good luck. 

[TheWhiteZombie]

Thanks @Cardiffman281, yeaah I tried calling the number which advised there were no faults in the area.

I will give the VM Customer Service number a call, but I've heard its nightmare trying to arrange an engineer, I will see what they say.

If theres anyone else from the VM Support team that can also help me out it would be greatly appreciated. Thanks, Mick.

[jbrennand]

Thats poor. We need the upstream pages too - but do this first...
__________________

Switch the Hub off and unplug it from the mains supply for five minutes. Whilst it's off, do a quick check that all of your coax and ethernet cable connections are in nice and "finger" tight - at the Hub and wall box and also at any connectors etc. Ensure there are no “unterminated cable loose ends. Disconnect all the connections and reconnect to be sure. Also check that the internal wiring is ok with no kinking or chaffing, check that all looks good with the outside cabling and wall box (no “staples, etc.,) piercing the cables. Then switch the Hub back on and leave ~5 minutes

When all done, check back in the settings and ensure that the RS error counts and T3 errors have all reset to 0. Then check every hour or so to see if they start reappearing - they shouldn't. If they do (particularly the postRS and T3 ones) you have a problem (noise) that only a Tech visit will sort.

[TheWhiteZombie]

Thanks John, apologies but I have double posted, I couldnt see that my first post had actually went live but you can find it over here:

https://community.virginmedia.com/t5/Networking-and-WiFi/Intermittent-Network-Dropouts-SYNC-Timing-S...

I am hoping a moderator can delete this particular post.

I will check the things you mention, thanks

[jbrennand]

Have merged the posts. If errors increasing call it in.

Are you in normal router mode or modem mode? If modem only, what router are you using ?

What devices have you got plugged into the Hub or Router on ethernet cables?

[TheWhiteZombie]

Thanks John, so I have my SH3 configured in a normal router mode but I have disabled the Wifi SSIDs, and I am using a 3rd party Asus RT AC68U.

I did have it initially configured in modem mode but without over complicating this particular post, it wasnt the best setup for me, mainly due to the way I wanted to allocate IP addresses and also helps me for troubleshooting connectivity issues either from the SH3 or Asus router.

My main home PC I have ethernet connected to the SH3 and all other devices are connected via WiFi to the Asus router.

I have had it setup this way for around 2.5 years and has been fine so far.

RE your earlier post, so I have confirmed from a cabling perspective that all cables are fine, tightened, no breaks in the cables I can see.

I did the full hard reboot at around 15:45 today and can confirm the stats on the router have successfully reset to 0.

I am running my continuous pings to local router, Google DNS and Virign DNS from my main PC and I have not yet seen any failed packets.

I have also not seen any Post RS Errors showing in the stats, and my Network Log has not registered any entries since 12:43 today.

I did call Virgin Support and have to say I got fantastic service from them, so credit where credit is due. They have arranged an engineer to attend on Tuesday but I will see how things go for tonight and tomorrow.

I will follow this post up with the stats from my router as its shows currently.