High Uncorrectable CM Error Codewords on Index 15, 16, and 17

[MrMinto]

Hello. For the last few weeks I've had a frequent packet loss, but only when gaming. I use Nvidia's Geforce NOW service, so it's basically some pretty hefty streaming. I haven't noticed any problems with Youtube or in day-to-day usage for work. I've had a tech come by twice to diagnose the problem, but it still persists.

On a whim, I decided to look into the modem's settings and logs and found the following.

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
1833858080	2356727543	2356733952	2356739876	2356743696	2356749523	2356755548	2356761194	2356766866	2356770283	2356773646	2356778670	2356759516	2356790373	2324515497	2203368013	2356182954	2356811883	2356815626	2356821646	2356826946	2356832476	2356838105	2356841563	2356845423	2356849799	2356855469	2356862331	2356866732	2356871123	2356873404	2356872286	1833858080
1762049352	0	0	0	0	0	0	0	0	0	0	0	0	0	27625326	60283957	615900	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1762049352
35	0	0	0	0	0	0	0	0	0	0	0	0	0	4656957	81839268	7580	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	35

Does anyone have any advice on how I can further diagnose this problem?

**Labels Added**

[-G-]

@MrMinto   From what you posted, there is a problem with a few of the DOCSIS 3.0 channels... but I don't think that those channels are actually being used.  I can't really say more because you did not post your downstream and upstream signal tables, and that is the information that we really need to assess the health of your modem's connection.

You also have a few uncorrectables on your downstream DOCSIS 3.1 channel, which is what should be carrying most (if not all) of your traffic.  However, this is a tiny number and really nothing to be concerned about, and the huge number of correctables on that channel is actually normal and totally fine.

[MrMinto]

Thanks for taking a look! I'm trying to figure out my packet loss issues are related to my internet, or if it's on Nvidia's side, so anything helps. All of this is a total mystery to me, but if it's OK I'd like to post the downstream/upstream signal tables.
DOWNSTREAM

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33

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693 MHz

279 MHz

849 MHz

855 MHz

861 MHz

579 MHz

585 MHz

591 MHz

597 MHz

603 MHz

609 MHz

615 MHz

621 MHz

633 MHz

639 MHz

645 MHz

651 MHz

657 MHz

663 MHz

669 MHz

675 MHz

681 MHz

687 MHz

699 MHz

705 MHz

711 MHz

717 MHz

723 MHz

825 MHz

831 MHz

837 MHz

843 MHz

350000000

42.8 dB

41.3 dB

42.1 dB

42.2 dB

42.5 dB

42.6 dB

42.6 dB

42.5 dB

42.5 dB

42.8 dB

42.6 dB

42.5 dB

42.3 dB

41.8 dB

29.5 dB

40.0 dB

40.8 dB

42.4 dB

42.2 dB

42.4 dB

42.3 dB

42.7 dB

42.8 dB

42.6 dB

42.7 dB

42.8 dB

42.9 dB

42.8 dB

42.2 dB

42.3 dB

42.1 dB

41.9 dB

41.3 dB

10.7 dBmV

6.6 dBmV

9.3 dBmV

9.6 dBmV

10.0 dBmV

9.5 dBmV

9.3 dBmV

9.3 dBmV

9.7 dBmV

10.4 dBmV

10.1 dBmV

9.5 dBmV

9.5 dBmV

9.5 dBmV

9.3 dBmV

9.0 dBmV

9.2 dBmV

9.7 dBmV

9.6 dBmV

9.5 dBmV

9.9 dBmV

10.6 dBmV

11.0 dBmV

10.1 dBmV

10.1 dBmV

10.3 dBmV

10.9 dBmV

10.6 dBmV

10.0 dBmV

10.1 dBmV

9.7 dBmV

9.0 dBmV

7.4 dBmV

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

UPSTREAM

1	2	3	4	5
Locked	Locked	Locked	Locked	Locked
21 MHz	25 MHz	32 MHz	38 MHz	4 MHz
2560	5120	5120	5120	0
37.3 dBmV	37.0 dBmV	38.3 dBmV	39.0 dBmV	36.0 dBmV
QAM	QAM	QAM	QAM	OFDMA
TDMA_AND_ATDMA	ATDMA	ATDMA	ATDMA	TDMA

And CM Error Codewords again for good measure.

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
2381439871	3230067167	3230072502	3230080682	3230084790	3230089518	3230095299	3230099438	3230104234	3230107015	3230110533	3230114667	3230096329	3230125658	3193565996	3050152141	3228685747	3230149739	3230153153	3230158983	3230163822	3230169453	3230175223	3230177582	3230182652	3230188806	3230194928	3230199677	3230203174	3230208170	3230209770	3230210834	2381439871
2271538911	0	0	0	0	0	0	0	0	0	0	0	0	0	31504169	75600133	1400920	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2271538911
35	0	0	0	0	0	0	0	0	0	0	0	0	0	5061781	92963188	56431	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	35

Thanks again!

[-G-]

@MrMinto  There are a few things that I see.  First, the power level on all the downstream channels is too high; it should average out at 0 dBmV across all channels.  Also, the power levels on the upstream side are too low; they should be in the low 40's.  Both can be fixed by adding an attenuator to the line, and your field tech(s) should have done this.  (Either that or the power levels were fine when the techs came by but Maintenance bumped them up when they tried to fix other problems in the area.)

The signal-to-noise ratio on your 639 MHz channel is also really bad, so there is definitely some interference/noise ingress that Rogers needs to address.

[-G-]

@MrMinto If you happen to have a two-way coax splitter (from a previous installation?) and a terminating cap (ships with your modem) on hand, you can craft your own attenuator: Connect the incoming Rogers coax feed to the splitter's input and connect one of the outputs to the line leading to your modem.  Connect the terminating cap to the other output on the splitter.

[MrMinto]

I do and the tech did install a splitter. I ended up moving my modem, and didn't reattach it in the same way, so that's on me. I'll do that shortly and report back.

[MrMinto]

For clarity, I did as described above with the splitter.

Downstream

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693 MHz

279 MHz

849 MHz

855 MHz

861 MHz

579 MHz

585 MHz

591 MHz

597 MHz

603 MHz

609 MHz

615 MHz

621 MHz

633 MHz

639 MHz

645 MHz

651 MHz

657 MHz

663 MHz

669 MHz

675 MHz

681 MHz

687 MHz

699 MHz

705 MHz

711 MHz

717 MHz

723 MHz

825 MHz

831 MHz

837 MHz

843 MHz

350000000

42.8 dB

41.6 dB

42.3 dB

42.2 dB

42.0 dB

42.8 dB

42.7 dB

42.6 dB

42.7 dB

42.7 dB

42.7 dB

42.5 dB

41.4 dB

38.2 dB

29.1 dB

28.1 dB

30.1 dB

42.3 dB

42.3 dB

42.4 dB

41.4 dB

42.5 dB

42.7 dB

42.8 dB

42.8 dB

42.8 dB

42.9 dB

42.7 dB

42.2 dB

42.2 dB

42.3 dB

42.1 dB

41.7 dB

7.1 dBmV

3.5 dBmV

5.7 dBmV

5.4 dBmV

5.2 dBmV

5.9 dBmV

5.9 dBmV

6.0 dBmV

6.3 dBmV

6.3 dBmV

6.2 dBmV

6.1 dBmV

5.9 dBmV

5.8 dBmV

5.7 dBmV

5.6 dBmV

5.6 dBmV

5.9 dBmV

5.8 dBmV

5.9 dBmV

6.3 dBmV

6.5 dBmV

6.8 dBmV

6.9 dBmV

6.7 dBmV

6.8 dBmV

6.8 dBmV

6.5 dBmV

5.9 dBmV

6.2 dBmV

6.0 dBmV

5.5 dBmV

4.0 dBmV

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

Upstream

1	2	3	4	5
Locked	Locked	Locked	Locked	Locked
21 MHz	25 MHz	32 MHz	38 MHz	4 MHz
2560	5120	5120	5120	0
39.3 dBmV	40.8 dBmV	42.3 dBmV	42.3 dBmV	39.2 dBmV
QAM	QAM	QAM	QAM	OFDMA
TDMA_AND_ATDMA	ATDMA	ATDMA	ATDMA	TDMA

CM Error Codewords

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
6379952	7703250	7707753	7712382	7716734	7721058	7725874	7730997	7735639	7740305	7742863	7747142	7751404	7756624	7647726	7410347	7770522	7775610	7780402	7784878	7788864	7794187	7798758	7803508	7808084	7813049	7817582	7822801	7827860	7832675	7834516	7836318	6379952
5718894	0	0	0	0	0	0	0	0	0	0	0	0	0	106859	260317	538	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	5718894
0	0	0	0	0	0	0	0	0	0	0	0	0	0	6680	95242	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

[-G-]

@MrMinto That's better.  Your signal levels are back within norms.

You said that you moved your modem.  There's nothing wrong with that ... but where is it currently connected in your home and what splitters, couples, wall plates, etc are on the signal path from the point that the Rogers line enters your home to the patch cable connecting to your modem?

The one other thing that you could try is to connect your gateway at the point of entry, with the attenuator/splitter in place to drop the signal levels.  If you still have problems with channels at or around 639 MHz, at least that will confirm that the interference is not coming from within your own home.

I would still contact Rogers (or send a private message to @CommunityHelps ) and have them run some tests on your line remotely.  I don't think that there is anything that you yourself can do about the bad SNR on that one channel or the uncorrectable errors on the D3.0 channels.

[MrMinto]

I'm not particularly familiar with the terminology, but here's how things are connected.

1. The line from outside the house goes to an external cable box. This cable used to be on a splitter, going to a downstairs coax and an upstairs coax, but since switching to Ignite, the splitter was removed and coupled to the upstairs coax.
2. The upstairs coax goes through my room wall (metal cover plate).
3. Upstairs coax goes into a splitter. A output connection has a cap on it. The other has the coax cable connected to the router.

[-G- · Accepted solution]

@MrMinto  Did you contact Tech Support (or @CommunityHelps ) to get some additional tests run on your line?  Has anything changed, for better or worse, since your last post?

Based on your description above, I would install the splitter/attenuator between the incoming coax feed at the point-of-entry and the coax line going to the wall place upstairs.  I would then connect a coax patch cable from the upstairs wall plate to the modem.

Anywhere that you have a coupler joining two coax segments together, whether it's a splitter, coax wall plate or an F81 barrel connector, that's a place where you could get noise ingress, so be sure to keep any devices that transmit in the HF, VHF and/or UHF bands away from there.

I'm at a loss for anything else to suggest.

[MrMinto]

Hi. Thank you for following up here, and yes, I contacted CommunityHelps, and they were able to do some tests and determine that the problem likely originates outside of the Roger's Network; so, at GFN's servers, or more likely, in the equipment between mine and theirs. Understandably, not much they can do as the tests on my line and equipment all came back optimal.

GFN has had me do a number of tests as well, but they've all been inconclusive, and neither I nor the Rogers tech were able to actually ping/trace-route their servers. So that portion of the route remains a mystery.

Thanks again for pointing me in the right direction. While I wasn't able to figure out the problem, I can mostly mitigate it by restarting a given game (and in doing so presumably rerouting the signal), and while a bit more time consuming, gets me to minimally disruptive packet/frame loss.