Hub 5 stuck on DOCSIS 3.0 – Ranging Failures, High Upstream Power, DOCSIS 3.1 Not Engaging

That’s a great question and honestly, it’s a bit confusing by design.

Just because your Hub shows DOCSIS 3.1 channels available or “locked” in the status page doesn’t necessarily mean your connection is actively using DOCSIS 3.1.

Here’s a quick breakdown:

• DOCSIS 3.1 channels can appear listed or even "locked", but your modem may still be operating in DOCSIS 3.0 mode if there's an issue with signal quality, provisioning, or upstream compatibility.
• In the status page, the “Cable Modem Status” or “Primary Downstream Channel” line will often say "DOCSIS 3.0" even when 3.1 is present that’s because it’s falling back to using 3.0 for actual data transport.
• You can sometimes tell from the logs errors like RNG-RSP, T3 timeouts, or No Unicast Maintenance opportunities suggest that DOCSIS 3.1 tried to engage but failed.
• The Configuration tab will often show “DOCSIS Mode: 3.1” regardless — that just means the modem supports DOCSIS 3.1, not that it’s currently using it.

The only definitive way to know if your line is actively running in DOCSIS 3.1 is:

1. If the modem status shows “DOCSIS 3.1” as the operational mode after startup, and
2. If you're using an OFDM (3.1) downstream and OFDMA (3.1) upstream profile, without it reverting.

In my case, it keeps reverting to 3.0 due to upstream power levels and ranging errors.

Hope that helps clarify!

Yes. I have even had support run a line check and been told nothing is wrong. I explained the error logs but get ignored. 52 dBmV upstream is out of spec.

While I agree that upstream power at 52 dBmV could point to physical issues, such as tap alignment or a failing amplifier in the cabinet, it's equally possible that this is a provisioning or CMTS configuration issue further upstream.

Given that DOCSIS 3.1 channels are present but not being utilised, and the Hub consistently falls back to DOCSIS 3.0 even after reprovisioning, it suggests a potential misconfiguration involving the upstream OFDMA profile, signal windows, or modem registration.

I'm happy to accept a technician visit, but the focus must be on signal alignment and CMTS-side provisioning, not simply replacing hardware or checking internal connections again.

Throughout this process, Virgin Media support has repeatedly blamed internal issues including unsupported claims that my local network setup was to blame, or that the Hub should be replaced, despite clear diagnostics pointing to a line or network-level fault. These repeated misdirections have delayed proper investigation.

I have now requested that this be escalated beyond Tier 1 and treated as a potential cabinet-side or provisioning issue, not an in-home or equipment fault.

DOCSIS Status Summary:

• DOCSIS mode: 3.1 (configuration tab shows DOCSIS 3.1)
• Cable modem status: Online – DOCSIS 3.0
• Downstream channels: 31 DOCSIS 3.0 channels locked (QAM256, SNR 40–41 dB)
• Upstream channels: 5 DOCSIS 3.0 (QAM64, Power 51.5–52.3 dBmV), 1 DOCSIS 3.1 (OFDMA at 47.5 dBmV)

DOCSIS 3.1 Channel Info:

• Downstream 3.1 Channel 37: Locked, 94 MHz width, QAM4096, RxMER 39 dB
• Upstream 3.1 Channel 10: 10.4 MHz width, QAM256, FFT 2K, OFDMA, 208 subcarriers

Example Logs:

• RNG-RSP power errors: “Commanded Power in Excess of 6 dB Below DRW”
• Repeated: T3/T4 timeouts, DHCP warnings, No Maintenance Broadcasts

3.0 Downstream channels

DOCSIS 3.0 Downstream Channels

DOCSIS 3.1 Downstream (OFDM)

DOCSIS 3.0 Upstream Channels

DOCSIS 3.1 Upstream (OFDMA)

Sure — here’s a representative sample from the modem logs on July 11, which I included in my complaint to VM. These aren’t isolated entries — this type of error pattern repeats frequently:

14:24:55 – RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value

14:24:36 – No Ranging Response received - T3 time-out

14:24:26 – No Maintenance Broadcasts for Ranging opportunities received - T2 time-out

14:24:06 – Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out

These are all upstream provisioning or signal faults — not typical user-side problems. They also correlate with performance drops.

For further context, here’s my ThinkBroadband BQM graph for the same date — you can clearly see the packet loss and jitter spikes that align with the logs:

Sorry for just posting log extracts — I didn’t want to overload the post with pages of logs.

Hi Nednats 👋 Thank you for your posts and welcome to the Virgin Media Community 🙂

We're sorry to hear about the issues you've been having 😔 How have things been since you posted?

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Please pop back to us at your earliest convenience.

Regards,
Daniel