Forum Discussion

skilmore's avatar
skilmore
Joining in
2 days ago

Recently upgraded to 1gbps, upload was good for a day, now only 25mbps with one upload channel

As per the title we were upgraded to a 1Gig connection last week and also given a new Hub 5 router. I switched it out on Thursday and day one everything was fine. I was getting ~950Mbps download, 105Mbps upload. Then early morning on day two the internet went off entirely a couple of times, and ever since coming back on whilst the download remains good, the upload has been cut to 20-25Mbps. 

Had a look at the router config and can see what must be the reason why, only one upload 3.0 channel. Max traffic rate for upload is set at 110000274 bps so that is correct.

There are a few critical errors on the log

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing

SYNC Timing Synchronization failure - Loss of Sync

Started Unicast Maintenance Ranging - No Response received - T3 time-out;

16 consecutive T3 timeouts while trying to range on upstream channel 3

I have turned it off/on again a few times, checked all the connections, still the same.

4 Replies

  • Nednats's avatar
    Nednats
    Settling in
    2 days ago

    I’ve been dealing with a very similar issue — high upstream power, frequent log errors, and upstream DOCSIS 3.1 not functioning properly. My upload dropped significantly too. VM support kept insisting it was my internal setup or the hub, it’s become clear this is likely signal or cabinet-side.  You’re not alone — here’s my thread if it helps for comparison Hub 5 stuck on DOCSIS 3.0 – Ranging Failures, High Upstream Power, DOCSIS 3.1 Not Engaging | Virgin Media Community - 5652510

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

    Try checking with Area faults on  0800 561 0061 or if you have a VM landline 150 as small local faults are not listed on the VM status page.

  • Client62's avatar
    Client62
    Alessandro Volta
    2 days ago

    It does look like a local fault for info ... 

    3.0 Upstream Power Levels of 35 to 49 dBmV are preferred, with QAM 64 Modulation mode across all four to six DOCSIS 3.0 channels.  Seeing QAM 32/16/QPSK is a current service noise fault.  Seeing less than four DOCSIS 3.0 channels is usually a signal level fault.

  • gitty's avatar
    gitty
    Joining in
    2 days ago

    Have you tried removing the cable, too see if there has been damage to it?