Intermittent connectivity issues with extremely high uncorrectable errors

[johnmfield]

I have been having intermittent connectivity issues ever since moving into my house two months ago. The previous owners used Fios, and I don't know whether they had any issues.

After moving in, the comcast tech connected by personally owned modem, an Arris TM722, connected to two eero pro routers. I had used that modem and routers at my previous residence without issue. However, after moving in, I began having intermittent connectivity issues where the internet would drop several times per day. It would come back on its own after a few minutes, or slightly faster if I reset the modem.

Since the modem was a few years old and couldn't actually support the speeds I was paying for, I upgraded to a brand new Netgear CM500V. The connectivity issues initially seemed better, but ultimately did not improve and the internet continued to drop several times per day. At this point a comcast tech came to look again. It seemed that some of the connections may have been lose. He checked the lines and the one splitter and claimed everything looked ok. He also set up an Xfinity Gateway device (Technicolor CGM4331COM) so that I could troubleshoot on my own, since the issue is intermittent and didn't present while he was here.

The issue continued with the Xfinity Gateway. I then went back to my CM500V but connected the device as close as possible to the point at which the cable enters my home. There is one splitter in the line and all connections have been tightened with a 7/16" wrench. I have also swapped all cables. None of this fixed the issue.

I spoke with Xfinity last week, but was told that I should contact Netgear and they couldn't help further. They said that in order for someone to come out, I needed to connect the xfinity gateway. I have now done so and am currently paying to rent the gateway. The issue has remained and I am seeing upwards of 22 million uncorrectable errors over the last 6 days on each channel. The uncorrectables were not nearly as high with the Netgear (maybe a few thousand per day), but were still there.

Based on all of this troubleshooting, I assume that the issue lies outside of my house. Unless there are other steps I haven't yet tried, I would like someone from xfinity to come and determine the true root cause of the issue. Below are the codeword errors seen over the last 6 days 6 hours. Every time I call xfinity they tell me they see no issues from their end. But as this is not a repeatable issue, this needs to be elevated beyond phone support.

 

[johnmfield]

Not sure if I need someone to approve the picture, but pasting the full stats in addition. Again, this is over 6 days 6 hours with the Technicolor gateway connected through a single splitter, with just a few feet of cable from the drop point.

Index	37	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	38	39	40	159
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Frequency	673 MHz	505 MHz	511 MHz	517 MHz	523 MHz	529 MHz	535 MHz	541 MHz	547 MHz	553 MHz	559 MHz	565 MHz	571 MHz	577 MHz	583 MHz	589 MHz	595 MHz	601 MHz	607 MHz	613 MHz	619 MHz	625 MHz	631 MHz	637 MHz	643 MHz	649 MHz	655 MHz	661 MHz	667 MHz	679 MHz	685 MHz	691 MHz	701 MHz	640350000
SNR	41.2 dB	41.6 dB	41.5 dB	41.6 dB	41.6 dB	41.7 dB	41.6 dB	41.6 dB	41.5 dB	41.7 dB	41.7 dB	41.9 dB	41.8 dB	42.0 dB	41.9 dB	41.6 dB	41.8 dB	42.0 dB	41.7 dB	41.6 dB	41.6 dB	41.6 dB	41.5 dB	41.4 dB	41.4 dB	41.5 dB	41.5 dB	41.5 dB	41.6 dB	41.5 dB	41.6 dB	41.8 dB	42.0 dB	NA
Power Level	1.2 dBmV	0.8 dBmV	0.6 dBmV	0.7 dBmV	0.8 dBmV	0.8 dBmV	0.8 dBmV	0.8 dBmV	0.5 dBmV	0.5 dBmV	0.6 dBmV	0.6 dBmV	0.5 dBmV	0.8 dBmV	0.8 dBmV	0.6 dBmV	0.7 dBmV	0.9 dBmV	0.6 dBmV	0.6 dBmV	0.7 dBmV	0.6 dBmV	0.4 dBmV	0.2 dBmV	0.2 dBmV	0.5 dBmV	0.6 dBmV	0.9 dBmV	1.0 dBmV	1.4 dBmV	1.8 dBmV	2.0 dBmV	3.3 dBmV	NA
Modulation	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	OFDM	OFDM
Upstream	Channel Bonding Value
Index	1	2	3	4
Lock Status	Locked	Locked	Locked	Locked
Frequency	36 MHz	30 MHz	23 MHz	17 MHz
Symbol Rate	5120	5120	5120	5120
Power Level	42.8 dBmV	43.8 dBmV	43.3 dBmV	43.8 dBmV
Modulation	QAM	QAM	QAM	QAM
Channel Type	ATDMA	ATDMA	ATDMA	ATDMA
CM Error Codewords
Index	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33
Unerrored Codewords	3802682388	3145774771	3145500530	3145818555	3145798606	3145726593	3145696266	3145546907	3145582391	3145556776	3145087615	3145193476	3145377682	3145287916	3145184505	3145200805	3144731360	3144731954	3145107228	3144484580	3144739274	3144813962	3144767605	3144607266	3144196509	3144480378	3144527469	3144381873	3144314409	3134380256	3144170520	3144150242	3802682388
Correctable Codewords	28310370	5171482	5159968	5208335	5226473	5246463	5265387	5278987	5305230	5331463	5327593	5360601	5406436	5423411	5445900	5483078	5468904	5494935	5554852	5550794	5603367	5647236	5683645	5713709	5724638	5774936	5798021	5816973	5842289	5749891	5914493	5957809	28310370
Uncorrectable Codewords	19182460	21645712	21629570	21825404	21911675	21962777	22022221	22038345	22105723	22172526	22097503	22191340	22323602	22367336	22386989	22463140	22327165	22409623	22594342	22441922	22624475	22726326	22781858	22814408	22733343	22915606	22990326	23005853	23044530	22399341	23176455	23229262	19182460

[EG]

The stats are good but there is a large number of uncorrectable errors.

Are there any error / event log entries being shown ? If so, please post them as well.

[johnmfield]

@EG, thanks for the reply.

I have since disconnected it, but here's a set of typical logs for the CM500V.

Where do I see the equivalent logs for the xfinity gateway? When I look at the Event Logs under troubleshooting at 10.0.0.1, I see a lot of Harverster messages - "Harvester StartRadioTrafficHarvesting" and "Harvester StartAssociatedDeviceHarvesting". Which I think is normal after a reboot, right? I don't see any T3 or T4 critical errors on the Event Log, which is where I assumed I would see them.

On the Firewall Logs, I see a number of FW.IPv6 FORWARD drops, FW.WANNATTACK DROPs, and FW.IPv6 INPUT drops. INPUT drops are fewer than 6 Attempts, FORWARD drops are up to 3000 attempts, and WANATTACK drops are fewer than 25 drops. 19 total entries over the last week. I can try and post the full list if helpful.

I don't have any logs from the Arris TM722, but I could hook it up for a bit if it would be useful.

[EG]

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@johnmfield wrote:

@EG, thanks for the reply.

I don't have any logs from the Arris TM722, but I could hook it up for a bit if it would be useful.

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If you could, please do so. 

O/k we've seen many posts here recently indicating that they have now blocked the end user from accessing the error log entries in the Comcast supplied gateway devices. A BIG mistake in my opinion......