VM issues on Lines and dropped connections
I have an issue with my internet the but stays connected but it loses connection for a few min's randomly though out the day from VM Services, I had the issue with there Business BB but they could not find the issue, using AI to examine the logs i have pulled together the below
đź“Ą DOCSIS 3.0 Downstream Channels
Metric | Value Range | Interpretation |
|---|---|---|
Power (dBmV) | 14.6 – 16.2 | Excellent. Ideal range is -10 to +10, but modern modems tolerate up to +15 |
SNR (dB) | 40 – 41 | Very good. Anything above 38 dB supports 256-QAM reliably |
Modulation | QAM 256 | High-efficiency modulation, standard for DOCSIS 3.0 |
RxMER (dB) | 40 – 41 | Consistent with SNR; confirms clean signal |
Pre RS Errors | Thousands per channel | Indicates noise or interference before error correction |
Post RS Errors | Hundreds to thousands per channel | These are uncorrectable—signal degradation is present |
🧠Conclusion: Your downstream signal is strong, but the Post RS errors suggest persistent low-level noise. It’s not catastrophic, but it’s not ideal either—especially for latency-sensitive applications.
📡 DOCSIS 3.1 Downstream Channel
Metric | Value | Interpretation |
|---|---|---|
Channel Width | 94 MHz | Wide OFDM channel—great for throughput |
FFT Type | 4K | 4096-point FFT—standard for DOCSIS 3.1 |
Modulation | QAM 4096 | Extremely high-order modulation—requires pristine signal |
RxMER | 42 dB | Excellent—supports 4096-QAM |
PLC Power | 14.8 dBmV | Within spec; PLC (Physical Link Channel) is healthy |
Corrected Errors | 3.53 billion | Indicates heavy reliance on FEC (Forward Error Correction) |
Uncorrectable Errors | 14,552 | These are concerning—data lost despite correction attempts |
🧠Conclusion: DOCSIS 3.1 is working, but the error volume is high. The modem is correcting billions of codewords, which suggests borderline signal quality. The presence of uncorrectable errors means some data is being dropped.
🔍 What’s Causing This?
- Ingress noise: Likely culprit for both RS and OFDM errors.
- Impedance mismatch or microreflections: Could explain why errors persist despite good power/SNR.
- Upstream instability: May be feeding back into downstream performance via profile shifts or CMTS compensation.
🛠️ What You Can Do
- Inspect coax path: Look for loose connectors, splitters, or damaged cable runs.
- Check grounding: Improper grounding can introduce noise.
- Log RxMER over time: Use SNMP or curl to track fluctuations.
- Contact ISP: Share these stats—especially the uncorrectable errors and upstream timeouts.
- Request line sweep or spectrum analysis: Engineers can identify ingress sources or impedance faults.
Would you like help building a curl-based polling tool to track RxMER and error counters in real time? Or maybe a script to visualize error trends across channels and correlate with timeouts?
apart from a engineer site visit booked any thing else I can look at.?
