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carlosp_uk's avatar
carlosp_uk
Tuning in
2 years ago

Struggling with frequent SYNC loss and customer support making me jump through hoops

Hi

My setup is that I use a VM Hub 3 in Modem Mode, with my own wireless router connected to it that provides our main home network.  We have had no issues for more than 2 years, and the more advanced setup suits us because our home network is quite complicated with wireless speakers, IOT devices, home assistant setup and so on.

In the last few weeks we've started to get frequent WAN drop-outs that seem to occur several times each day for up to 30 seconds at a time.  Internal wifi was fine, I checked our router logs and ultimately traced it to the VM Hub itself.

Via the Hub's network tools / logs, I have uncovered what appears to be a frequent loss of synchronisation - I'll post the full output (log, downstream, upstream, etc.) but we get this 5-6 times per day:

 

criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

From my perspective, this absolutely correlates with what's been going on.  We've had a lot of building work around here recently, plus lorries are always reversing into the grey on-street cabinets so it wouldn't surprise me if there is an issue with line noise or connectivity.

From my perspective, that should be enough to get a technician to visit and examine the street cabling, fibre box etc.

But, on the phone, customer support are now insisting that I re-enable Router mode on the hub, turn off our own router completely, and run a 48 hour 'experiment' to rule out what I presume is issues with our router, etc.  This is pretty disruptive.

It also feels a little pointless. Why am I having to jump through these hoops, have I missed something here or are the critical log entries in the Hub not sufficient evidence that we need somebody to check the on-street connection to the cabinet?  Is there no other way?

I actually work in an I.T. company but of course I also acknowledge I'm no expert in DOCSIS, fibre, etc. so I don't want to sound arrogant - hence the community post to canvas opinion on this!

13 Replies

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  • carlosp_uk's avatar
    carlosp_uk
    Tuning in
    2 years ago

    Downstream bonded channels

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

    1138750000336256 qam1
    21467500002.936256 qam2
    31547500003.237256 qam3
    41627500002.938256 qam4
    51707500003.238256 qam5
    6178750000338256 qam6
    71867500003.238256 qam7
    81947500002.938256 qam8
    92027500002.938256 qam9
    102107500002.738256 qam10
    112187500002.536256 qam11
    122267500002.737256 qam12
    132347500002.538256 qam13
    142427500002.238256 qam14
    152507500002.538256 qam15
    162587500001.938256 qam16
    172667500001.738256 qam17
    182747500001.938256 qam18
    192827500001.738256 qam19
    202907500001.538256 qam20
    212987500002.438256 qam21
    22306750000238256 qam22
    23314750000238256 qam23
    243227500002.538256 qam24



    Downstream bonded channels

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

    1Locked36.64286842522302
    2Locked36.64173574116440
    3Locked37.623641659039
    4Locked38.917472678802
    5Locked38.6169367110
    6Locked38.62090127046
    7Locked38.61201367367
    8Locked38.9119867603
    9Locked38.984166535
    10Locked38.921256226373
    11Locked36.6215921714578
    12Locked37.6155066957
    13Locked38.6556134727
    14Locked38.934646375
    15Locked38.994305443
    16Locked38.645354490
    17Locked38.668006579
    18Locked38.925424670
    19Locked38.622463471
    20Locked38.920165091
    21Locked38.917693692
    22Locked38.921992771
    23Locked38.920064084
    24Locked38.616363260
  • carlosp_uk's avatar
    carlosp_uk
    Tuning in
    2 years ago

    Upstream bonded channels

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

    13940000037512064 qam4
    24620000037.5512064 qam3
    36030000037.5512064 qam1
    42360000036.8512064 qam10



    Upstream bonded channels

    Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

    1ATDMA0000
    2ATDMA0000
    3ATDMA0000
    4ATDMA0000
  • carlosp_uk's avatar
    carlosp_uk
    Tuning in
    2 years ago

    Network Log

    Time Priority Description

    05/03/2024 13:14:50noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 12:40:56Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 12:26:11noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 12:25:34Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 12:25:25Warning!LAN login FAILED : Incorrect Username / Password / ConnectionType;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 12:16:17Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 12:16:16criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 11:51:20Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 11:13:50noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 11:13:47Warning!LAN login FAILED : Incorrect Username / Password / ConnectionType;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 10:56:32Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 10:56:25criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 10:55:48Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 10:55:17criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 10:54:42Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 10:54:41criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 08:33:37Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 08:33:36criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 07:44:56Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
    05/03/2024 07:44:55criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
  • Adduxi's avatar
    Adduxi
    Very Insightful Person
    2 years ago

    Unfortunately VM will insist on the Hub being in Router mode for their troubleshooting.  You will need to do a 60 second pinhole reset and then check the logs and PostRS errors.  Ideally they should remain at zero.  Rising PostRS errors usually are a noise ingress problem.  SYNC errors relate to mostly Upstream problems but you don’t seem to have any T3 errors.

    • carlosp_uk's avatar
      carlosp_uk
      Tuning in
      2 years ago
      Adduxi wrote:

      You will need to do a 60 second pinhole reset and then check the logs and PostRS errors.


      They only had me do a 15 second reset, which kicked the hub out of Modem Mode and seems to have reset the firmware.  Logs have survived though.

      Have I missed out on some additional benefit of the longer reset?

  • Client62's avatar
    Client62
    Alessandro Volta
    2 years ago

    The 60 second RESET is required to trigger a complete return to the shipping condition, 
    if the old logs are still present that full reset did not happen.

    VM may not care how you switch to Router mode ( by reset or by the menu ).
    In Modem mode VM can not remote access the state of the Hub.

  • carlosp_uk's avatar
    carlosp_uk
    Tuning in
    2 years ago

    Thanks all.

    Today’s update: 

    I’ve been running the hub in Router Mode as requested for 24 hours. One more day to go before a follow up with support. 

    As predicted, it has made no difference, we are still getting WAN disconnection and the same SYNC errors are still accumulating in the hub’s log. Each loss of Internet connectivity coincides directly with the log messages. 

    I can only hope this is enough to persuade the phone support team tomorrow to send out an engineer. This is a miserable experience - I wish they had just believed me in the first place. 

  • Adduxi's avatar
    Adduxi
    Very Insightful Person
    2 years ago

    In the meantime setup a BQM ( if you haven't already?) and this will monitor your circuit.   www.thinkbroadband.com/ping

    Post a link to the live shared graph for comments.  It's also evidence for any discussions with VM btw.  

    • carlosp_uk's avatar
      carlosp_uk
      Tuning in
      2 years ago

      Good suggestion - I already set up my own external monitoring script. I might do this one too. 

  • Adduxi's avatar
    Adduxi
    Very Insightful Person
    2 years ago

    That's not a great start for a BQM.  Should get a better picture after 24 Hours.

  • carlosp_uk's avatar
    carlosp_uk
    Tuning in
    2 years ago

    Nearly at the end of the 48 hour 'test' and we had another 2 days of frequent loss of Internet connectivity, between 20-30 times per day.

     

    My Broadband Ping - My VM Internet Connection

     

    All it has done is seem to confirm what I knew already - the problem is not on our side of the Hub. 

    I really hope I can get the phone support person to agree to send out an engineer now, we can't go on like this!

    • Daniel_Et's avatar
      Daniel_Et
      Icon for Forum Team rankForum Team
      2 years ago

      Hi carlosp_uk 👋 Thank you for your posts and welcome to the Virgin Media Community 😀

      We're sorry to hear about the problem you've been experiencing 😔

      In order to discuss this with you further, we'll send you a private message on here. Look out for the envelope in the top right-hand corner.

       

      If you're on a portable device with a smaller screen, click on the icon in the top right-hand corner and select "messages" from the additional menu options.

      Thank you for your support Adduxi and Client62 👍

      Regards,
      Daniel