SB6121 issues with heavy uploading

[cbfiddle]

I recently started using a cloud backup service. The initial upload takes weeks, probably, and originally used the full 6MB upload capacity. I started having problems where the internet connection dropped, which were solved by power cycling the modem. The backup service support person suggested dialing back the program to use 1MB upload, and since then the internet connection has not dropped. As I am supposed to get 6MB, this seems like a problem.

The upstream power levels I get are 38–42 dBmV, which is low. (Downstream S/N are 36–37 dB.)

The error log shows messages like this:

MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=94:cc:b9:d0:42:8d;CMTS-MAC=00:9e:1e:58:cd:d2;CM-QOS=1.1;CM-VER=3.0;

Seems like there is one of these for each power reset message.

Suggestions?

[mrumppe]

Due to when the 6121 was released it's getting a bit long in the tooth / EOL\EOS potentially as well.

If you can login and grab a snapshot of the power/snr levels from the modem admin page that would be helpful to see if there's a potential line issue or a splitter gone wrong.  

[cbfiddle]

I think I already provided that information...

[ComcastJoeTru]

Hello cbfiddle. I can assist with troubleshooting your upload performance issues. I'd like to start with performing a diagnostics test against your modem. Please send me a private message and include your full name, service address, and account number so I can access your account.

[EG]

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@cbfiddle wrote:

The upstream power levels I get are 38–42 dBmV, which is low.  

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FWIW, no they are not low. They are o/k.

[ArrisTuska]

Comcast should be helping you on the RF issues..

Upstream Rx Power     
-0.5     0.0     0.0     0.5
Upstream SNR Ch     
34.3     36.5     37.8     37.5

Upstream ICFR     
1.5     1.61     1.68     2.44
Upstream Ripples     
2     4     4     4

Down FEC Corrected     
1.0E-5     1.0E-5     1.0E-5     9.9E-6
Down FEC Uncorrectable     
4.3E-7     4.4E-7     4.6E-7     4.4E-7
Up FEC Corrected     
1.2E-4     1.2E-4     1.2E-4     1.2E-4
Up FEC Uncorrectable     
3.3E-6     3.3E-6     3.3E-6     3.3E-6

[ComcastJoeTru]

I agree @ArrisTuska. I am waiting on the private message to be able to access the account, per our security policy. 

[cbfiddle]

Three days ago, a Comcast tech came out and replaced a cable.

The modem worked fine for two days after that, but froze 3 times yesterday. When frozen, even the modem admin page does not respond. I have attached the modem status information.

[ComcastJoeTru]

@cbfiddle, We apologize you are still experiencing issues. Can you please retest today and provide new speed test results? I also responded to your private message. 

[cbfiddle]

I also observe that the hangs almost always occur when I am web browsing (and the cloud backup is uploading). Makes me think there is some sort of conflict between the two activities.

Speed test 82.58 / 6.22, second time 80.78/5.94

Channel ID	13	14	15	16
Frequency	585000000 Hz	591000000 Hz	597000000 Hz	603000000 Hz
Signal to Noise Ratio	37 dB	37 dB	37 dB	37 dB
Downstream Modulation	QAM256	QAM256	QAM256	QAM256
Power Level The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading	4 dBmV	3 dBmV	4 dBmV	4 dBmV

Upstream	Bonding Channel Value
Channel ID	1	2	3	4
Frequency	35700000 Hz	29200000 Hz	22700000 Hz	16200000 Hz
Ranging Service ID	13	13	13	13
Symbol Rate	5.120 Msym/sec	5.120 Msym/sec	5.120 Msym/sec	5.120 Msym/sec
Power Level	34 dBmV	34 dBmV	32 dBmV	31 dBmV
Upstream Modulation	[2] QPSK [1] 16QAM [3] 64QAM	[2] QPSK [1] 16QAM [3] 64QAM	[2] QPSK [1] 16QAM [3] 64QAM	[2] QPSK [1] 16QAM [3] 64QAM
Ranging Status	Success	Success	Success	Success

Signal Stats (Codewords)	Bonding Channel Value
Channel ID	13	14	15	16
Total Unerrored Codewords	1087678836	1085704669	1085704848	1085704677
Total Correctable Codewords	31	21	19	16
Total Uncorrectable Codewords	740	579	548	551

[ComcastJoeTru]

Hi cbfiddle. I would like to poll out CMTS again for the historical signal plots. Due to our security policy so that I can access your account, please send me a private message and include your full name, service address, and account number so I can assist you. 

[jweaver0312]

Old thread being locked.