Forum Discussion

klynchk's avatar
klynchk
Up to speed
30 days ago

[Hub 5] Recurring T3 Timeouts causing intermittent connection drops - Log attached

I am experiencing intermittent connection drops multiple times a week. I have extracted the router log from my Hub 5 and can see consistent critical T3 timeout errors.

This suggests a fault with the signal levels or connection stability to the CMTS.

Can the VM team please investigate the line quality for T3 timeout issues?

Device Details:

  • Equipment: Virgin Media Hub 5
  • Cable MAC: 9C:24:72:XX:XX:XX (The full, non-anonymised version is best for staff).

Log Snippet showing T3 Errors:

2025-11-05 02:04:13,critical,Cable Modem Reboot because of - unknown 2025-11-04 07:33:10,critical,Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=9c:24:72:XX:XX:XX;CMTS-MAC=18:59:f5:25:f4:ec;CM-QOS=1.1;CM-VER=3.1; 2025-10-29 18:49:49,critical,Started Unicast Maintenance Ranging - No Respo

Full log with anonymised MAC address

10 Replies

  • This post has my screenshots of the broadband quality monitor

    https://community.virginmedia.com/discussions/Wireless/hub-5-recurring-t3-timeouts-causing-intermittent-connection-drops---log-attached/5681001/replies/5681625

    • Kath_P's avatar
      Kath_P
      Icon for Forum Team rankForum Team

      Hi klynchk, 

      Thanks for coming back to us on this. Checking things here, we can see some of your levels are out of the optimal range, as mentioned by newapollo. We won't be able to fix this remotely so I would like to arrange for an engineer to come to take a look at this for you. 

      I just need to confirm the address to ensure we are booking the visit on the correct account. I have sent you a direct message to allow us to do this with you in a private space. Just click on the little ✉ at the top right-hand side of the page to access your inbox. 😊

      Thanks, 

    • newapollo's avatar
      newapollo
      Very Insightful Person

      As indicated in my previous reply, the forum team won't have the necessary permissions to look at the networks logs you've posted due to the link going to an external site (google sheets)

      You should have  ideally copy pasted those logs into this thread - the forum team would then have been able to see that your downstream levels are far too high.

      3.0 Downstream channels
       
      Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
      1 306000000 15.1 42 QAM 256 22
      2 138000000 12.8 41 QAM 256 1
      3 146000000 12.9 41 QAM 256 2
      4 154000000 13 41 QAM 256 3
      5 162000000 13 41 QAM 256 4
      6 170000000 12.8 41 QAM 256 5
      7 178000000 13.2 42 QAM 256 6
      8 186000000 13.5 42 QAM 256 7
      9 194000000 14.3 42 QAM 256 8
      10 202000000 14.3 42 QAM 256 9
      11 210000000 14.7 42 QAM 256 10
      12 218000000 14.5 42 QAM 256 11
      13 226000000 14.7 42 QAM 256 12
      14 234000000 14.7 42 QAM 256 13
      15 242000000 14.7 42 QAM 256 14
      16 250000000 14.6 42 QAM 256 15
      17 258000000 14.6 42 QAM 256 16
      18 266000000 14.6 42 QAM 256 17
      19 274000000 14.8 42 QAM 256 18
      20 282000000 15 42 QAM 256 19
      21 290000000 15.2 42 QAM 256 20
      22 298000000 15.2 42 QAM 256 21
      23 314000000 15 42 QAM 256 23
      24 322000000 15 42 QAM 256 24
      25 330000000 15 42 QAM 256 25
      26 338000000 15.1 43 QAM 256 26
      27 346000000 14.9 43 QAM 256 27
      28 354000000 15 43 QAM 256 28
      29 362000000 14.8 42 QAM 256 29
      30 370000000 15.3 43 QAM 256 30
      31 378000000 15.2 43 QAM 256 31
      32 386000000 15.4 42 QAM 256 32
       
      3.0 Downstream channels
       
      Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
      1 Locked 42 135 0
      2 Locked 41 184 0
      3 Locked 41 189 0
      4 Locked 41 169 0
      5 Locked 41 151 0
      6 Locked 41 127 0
      7 Locked 42 105 0
      8 Locked 42 113 0
      9 Locked 42 79 0
      10 Locked 42 93 0
      11 Locked 42 87 0
      12 Locked 42 84 0
      13 Locked 42 69 0
      14 Locked 42 99 0
      15 Locked 42 92 0
      16 Locked 42 84 0
      17 Locked 42 90 0
      18 Locked 42 85 0
      19 Locked 42 88 0
      20 Locked 42 101 0
      21 Locked 42 90 0
      22 Locked 42 83 0
      23 Locked 42 92 0
      24 Locked 42 143 0
      25 Locked 42 177 0
      26 Locked 43 118 0
      27 Locked 43 131 0
      28 Locked 43 158 0
      29 Locked 42 172 0
      30 Locked 43 189 0
      31 Locked 43 144 0
      32 Locked 42 259 0
       
      3.1 Downstream channels
       
      Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)
      159 92 4K 1800 QAM 4096 1128
       
      3.1 Downstream channels
       
      Channel ID Locked Status RxMER Data (dB) PLC Power (dBmV) Corrected errors (Active Profile) Uncorrectable errors (Active Profile)
      159 Locked 0 15.9 1008174781 0

       

      3.0 Upstream channels

           
            
      ChannelFrequency (Hz)Power (dBmV)Symbol Rate (ksps)ModulationChannel ID
      04960000039.85120QAM 649
      14310000039.35120QAM 6410
      23660000039.35120QAM 6411
      33010000039.35120QAM 6412
      42360000038.55120QAM 6413
            

      3.0 Upstream channels

           
            
      ChannelChannel TypeT1 TimeoutsT2 TimeoutsT3 Timeouts

      T4 Timeouts

      0ATDMA0030
      1ATDMA0010
      2ATDMA0000
      3ATDMA0000
      4ATDMA0010
            

      3.1 Upstream channels

           
            
      ChannelChannel Width (MHz)Power (dBmV)FFT TypeModulation 
      141033.72KQAM 256 
            

      3.1 Upstream channels

           
            
      ChannelChannel TypeNumber of Active SubcarriersFirst Active Subcarrier (Hz)T3 Timeouts

      T4 Timeouts

      14OFDMA2007400000000

       

  • I can't attach a PDF either

    Mod Edit : Personal information removed

     

    • newapollo's avatar
      newapollo
      Very Insightful Person

      The forum team won't have the necessary permissions to look at the networks logs you've posted due to the link going to an external site (google sheets)

      It would actually be more useful for them, and the forum gurus, if you copy pasted the information from the Downstream and Upstream logs.

      You should also set up a quality monitor (BQM) on /thinkbroadband.com/broadband/monitoring/quality 

      • klynchk's avatar
        klynchk
        Up to speed

        Interesting my reply with requested info does not post - the logs you mentioned are in that spreadsheet

  • I didn't notice any issues - I have a think broadband monitor configured - do the dropped packets point to my issue?

    Yesterday 10 Nov

    Sun 09 Nov

     

    Sat 08 Nov


    Fri 07 Nov


    Thu 06 Nov

     

  • Hey klynchk, thank you for reaching out and we are so sorry to hear about your connection issues.

    We've taken a look and currently they are looking okay, how has it been over the weekend?