Network issue - logs provided

Question

Hello everyone,I’ve been a happy VM customer for around six years. I run the Gig1 service using a Hub 5 (normally in modem mode) with a Deco XE75 mesh system. It has been great for the last 18 months with virtually zero downtime.On Friday afternoon we temporarily switched off the electrics for some bathroom work. This may be unrelated, but roughly two hours later our broadband went down and has been mostly unusable since. We appear to be the only property on the street affected.The connection occasionally comes back for a few minutes, but then drops again. For the most part it has been completely unreliable, to the extent that my wife can’t rely on it for work.I’ve spoken to VM support three times and have an engineer booked for Wednesday. I reset the Hub 5 back into router mode so VM could view the logs. The Hub status consistently reports “Partial Service – DS Only”.After looking through the Hub logs in detail (with some help from ChatGPT), it appears the problem may require a network engineer, not just a standard home visit. The DOCSIS 3.1 downstream channel seems to be failing to lock, with extremely low PLC power, 0 dB MER, and very high uncorrectable error counts.Before the engineer arrives, I’d be grateful if anyone could look at the logs (posted below) and advise what the values mean and whether a standard engineer visit is indeed appropriate.Any guidance would be hugely appreciated.Thanks very much in advance.3.0 Downstream Channels (Error Counts)ChannelStatusRxMER (dB)Pre RS ErrorsPost RS Errors1 to 32All Locked39 to 41003.1 Downstream Channels (OFDMA)Channel DetailsChannelWidth (MHz)FFT TypeActive SubcarriersModulationFirst Active Subcarrier (Hz)159944K1840QAM40961108Channel PerformanceChannel IDStatusRxMER (dB)PLC Power (dBmV)Corrected ErrorsUncorrectable Errors159Locked0-27.94,045,7981,237,666,7093.0 Upstream ChannelsPower and ModulationChannelFrequency (Hz)Power (dBmV)Symbol Rate (ksps)ModulationChannel ID04960000042.85120QAM64114310000042.35120QAM64223660000041.35120QAM64333010000041.35120QAM64442360000040.85120QAM645Timeout SummaryChannelTypeT1T2T3T40ATDMA00001ATDMA00302ATDMA00003ATDMA00004ATDMA00003.1 Upstream ChannelsBasic DetailsChannelWidth (MHz)Power (dBmV)FFT TypeModulation61037.52KQAM256Channel PerformanceChannelTypeActive SubcarriersFirst Active Subcarrier (Hz)T3 TimeoutsT4 Timeouts6OFDMA2007400000000&nbsp;

Roger_Gooner · Answer

A network engineer doesn't do home visits, and bearing in mind that the problem could easily be the result of excess attenuation in the home or an issue in the cabinet, then a tech is the right person to be called out. Occasionally the drop cable is faulty. It's only if the problem is upstream of the cabinet (possible but unlikely as your DOCSIS 3.0 carriers are perfect) that networking need get involved.

Don't let the tech go until you've checked the PLC power level again, should be between about −10 dBmV and +10 dBmV and not the high −20s.

Client62 · Answer

Here is the issue, the 3.1 Downstream channel power has dropped very low to -27.9 dBmV ( preferred range is about -7 to + 7 dBmV) and the result is many millions of Uncorrectable Errors.

This is such a severe loss of signal I'd suggest a fault on the VM Network or at a local Street Cabinet. Given the 3.0 channel stats look ok, I'd expect folks local to you to be suffering the same service issue.

Check for known faults in your street. Try both methods:

Call the local fault line: 0800 561 0061 – this is an automated number.

https://www.virginmedia.com/help/check/status/identification/identify

As ever with VM Faults, someone has to be the first to report it !

3.1 Channel Performance

Channel ID	Status	RxMER (dB)	PLC Power (dBmV)	Corrected Errors	Uncorrectable Errors
159	Locked	0	-27.9	4,045,798	1,237,666,709

troutiesam · Answer

Thanks for your thoughts.&nbsp; Strange as all neighbours suggesting their VM provided broadband is fine.&nbsp; Further, there are no faults identified on either the website or via the telephone number you provided. Very strange!

Client62 · Answer

-27.9 dBmV&nbsp;&nbsp; is so low I am quite amazed there is a channel at all.

troutiesam · Answer

I tried calling VM again to ask for this to be escalated to the networks team.&nbsp; I've now got two appointments booked (I think).&nbsp; The second is a cabinet check.&nbsp; I guess it might help if I show the engineer who turns up at the house this thread.&nbsp;

Channel	Width (MHz)	Power (dBmV)	FFT Type	Modulation
6	10	37.5	2K	QAM256

Channel	Type	Active Subcarriers	First Active Subcarrier (Hz)	T3 Timeouts	T4 Timeouts
6	OFDMA	200	74000000	0	0

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Network issue - logs provided

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Channel	Frequency (Hz)	Power (dBmV)	Symbol Rate (ksps)	Modulation	Channel ID
0	49600000	42.8	5120	QAM64	1
1	43100000	42.3	5120	QAM64	2
2	36600000	41.3	5120	QAM64	3
3	30100000	41.3	5120	QAM64	4
4	23600000	40.8	5120	QAM64	5

Channel	Type	T1	T2	T3	T4
0	ATDMA	0	0	0	0
1	ATDMA	0	0	3	0
2	ATDMA	0	0	0	0
3	ATDMA	0	0	0	0
4	ATDMA	0	0	0	0