Forum Discussion

Yorkshirelion's avatar
Yorkshirelion
Tuning in
5 hours ago

Packet loss issue?

Hi, I seem to be having packet loss issues at the moment, very evident when playing online games, or running any test I will see the packet loss noted at around 3%.

I ran my Hub stats into AI and got the following;

  1. Downstream Power Levels
  • Range: from +3.7 dBmV (channel 11) down to +0.7 dBmV (channels 28-30)
  • Ideal range for Virgin: -6 to +10 dBmV, recommended ±7 dBmV, best within ±5 dBmV

Your levels are technically within spec, but the spread is about 3 dB across the band and they tilt downwards with frequency (lower frequencies stronger, higher frequencies weaker).
The lowest channels are sitting at +0.7 to +0.9 dBmV – this is very close to the bottom edge of acceptable. Virgin’s own engineers often say anything under +1 dBmV starts to become marginal, especially if it drops further in hot weather or with temperature changes.2. Downstream SNR / RxMER

  • 3.0 channels: 36–38 dB → perfectly fine for QAM256 (needs >33-34 dB minimum)
  • 3.1 channel (OFDMA): the RxMER column shows “0” which is normal – it’s not reported the same way. The important figure is the PLC Power at +2.5 dBmV – healthy.

No noise issues visible here.3. Error counters – this is the key part3.0 channels (QAM256):

  • Almost completely clean – only a handful of Pre-RS errors on the very lowest frequency channels and zero Post-RS (uncorrectable) errors on any 3.0 channel.
  • This is excellent – basically no packet loss coming from the 3.0 part of the spectrum.

3.1 channel (channel 159 – the high-split OFDMA channel that carries most of your speed):

  • Corrected errors: 582,918,780
  • Uncorrectable errors: 0

That corrected number is huge – over half a billion FEC-corrected codewords.
But crucially zero uncorrectables.What this means: The 3.1 channel is having to work quite hard correcting errors (likely because some of your downstream power levels are on the low side and possibly some ingress/noise on the higher frequencies), but the modem is successfully correcting everything before it turns into actual packet loss.So right now you are not seeing packet loss that reaches your devices – the hub is fixing it all at the physical layer.

So it would seem that I am not getting any packet loss, however when you look at the thinkbroadband BQM you can see the packet loss.

What can I do about this?

Also my upload speed is currently around 22Mbps on the Gig1 plan.

packet loss

4 Replies

  • Harper_King's avatar
    Harper_King
    Joining in
    2 hours ago

    Your hub is correcting all errors on the 3.1 channel, so real packet loss isn’t reaching your devices. The ThinkBroadband BQM loss is likely in the ISP network. Check wired vs Wi-Fi, monitor peak times, and contact Virgin support about the high FEC corrections and low upstream speed.

  • Adduxi's avatar
    Adduxi
    Very Insightful Person
    4 hours ago

    What Hub are you using?  Post the power levels and network log for comment please.  Check your connections from the Hub to the outside,  they should be "finger" tight and no sign of corrosion.

    Run the full speed tests here  http://www.samknows.com/realspeed and post the results.  Preferably with a wired connection.

    • Yorkshirelion's avatar
      Yorkshirelion
      Tuning in
      3 hours ago

      I think I have possibly fixed the issue now, please tell me if I'm wrong.

      I went and had a look outside at the brown box, it is sealed but the equipment wasn't screwed in all the way etc and the box whilst sealed wouldn't take much to open.

      I disconnected the fibre connected, not the coax convertor just the fibre part and now it appears that I have fixed that issue but my upload is still capped at a very low speed possibly due to all the line errors I was having. Here are the stats now since I have reseated the fibre cable.

      Downstream Channel | Frequency (Hz) | Power (dBmV) | SNR (dB) | Modulation | Channel ID ---|---|---|---|---|--- 1 | 379000000 | 1.1 | 38 | QAM 256 | 31 2 | 139000000 | 2.8 | 37 | QAM 256 | 1 3 | 147000000 | 2.7 | 37 | QAM 256 | 2 4 | 155000000 | 2.8 | 38 | QAM 256 | 3 5 | 163000000 | 2.9 | 38 | QAM 256 | 4 6 | 171000000 | 2.9 | 38 | QAM 256 | 5 7 | 179000000 | 3.1 | 38 | QAM 256 | 6 8 | 187000000 | 3.3 | 38 | QAM 256 | 7 9 | 195000000 | 3.7 | 38 | QAM 256 | 8 10 | 203000000 | 3.8 | 38 | QAM 256 | 9 11 | 211000000 | 3.9 | 38 | QAM 256 | 10 12 | 219000000 | 3.7 | 38 | QAM 256 | 11 13 | 227000000 | 3.4 | 38 | QAM 256 | 12 14 | 235000000 | 3.2 | 38 | QAM 256 | 13 15 | 243000000 | 2.9 | 38 | QAM 256 | 14 16 | 251000000 | 2.5 | 38 | QAM 256 | 15 17 | 259000000 | 2.1 | 38 | QAM 256 | 16 18 | 267000000 | 1.8 | 38 | QAM 256 | 17 19 | 275000000 | 1.5 | 38 | QAM 256 | 18 20 | 283000000 | 1.4 | 38 | QAM 256 | 19 21 | 291000000 | 1.3 | 38 | QAM 256 | 20 22 | 299000000 | 1.2 | 38 | QAM 256 | 21 23 | 307000000 | 1.3 | 38 | QAM 256 | 22 24 | 315000000 | 1.5 | 38 | QAM 256 | 23 25 | 323000000 | 1.5 | 38 | QAM 256 | 24 26 | 331000000 | 1.3 | 38 | QAM 256 | 25 27 | 339ッチ000000 | 1.1 | 38 | QAM 256 | 26 28 | 347000000 | 1.1 | 38 | QAM 256 | 27 29 | 355000000 | 0.9 | 38 | QAM 256 | 28 30 | 363000000 | 0.9 | 37 | QAM 256 | 29 31 | 371000000 | 1.0 | 38 | QAM 256 | 30 32 | 387000000 | 1.0 | 38 | QAM 256 | 32 Downstream (Post RS Errors) Channel | Locked Status | RxMER (dB) | Pre RS Errors | Post RS Errors ---|---|---|---|--- 1 | Locked | 38 | 0 | 0 2 | Locked | 37 | 0 | 0 ... (and the rest exactly the same – all zeros in your case) 3.1 Downstream Channel Channel ID | Locked Status | PLC Power (dBmV) | Corrected | Uncorrectable ---|---|---|---|--- 159 | Locked | 2.8 | 14539533 | 0

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

        If you suspect the fibre to be in anyway compromised you should insist on a tech visit.  Fibre needs careful handling as any speck of dirt will affect the light levels.  As for the 3.1 correctable, that’s over 14 million is a short time. Mine, by comparison, is about 1.2 million over 2 months of uptime.  Something is amiss.