aoberdeck's profile

Regular Visitor

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4 Messages

Tue, Dec 8, 2020 4:00 PM

Packet Loss and Low Upstream Power Levels

I'm experiencing upstream packet loss anywhere from 8%-15% during working hours.  Is this just network congestion due to working and schooling from home?  It obviously makes video and VoIP extremely challenging.  It seems to work fine from 6:00 pm until 8:30 am, and fine on weekends.

 

I've had two technicians out to check the connection.  They replaced some cables and removed a splitter, but the problem persists.

 

The modem (SB8200) shows low upstream power levels, which I've pasted below. 

 

I'd appreciate any help or guidance.

 

aoberdeck_0-1607473601436.png

 

Responses

Regular Visitor

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4 Messages

6 m ago

Here are the power levels:

 

Downstream Bonded Channels
Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
33LockedQAM256663000000 Hz5.9 dBmV40.4 dB40
5LockedQAM256483000000 Hz2.4 dBmV39.7 dB40
6LockedQAM256489000000 Hz2.0 dBmV39.7 dB120
7LockedQAM256495000000 Hz1.8 dBmV39.7 dB10
8LockedQAM256507000000 Hz3.8 dBmV40.4 dB00
9LockedQAM256513000000 Hz4.1 dBmV40.6 dB10
10LockedQAM256519000000 Hz3.2 dBmV40.1 dB00
11LockedQAM256525000000 Hz2.0 dBmV39.6 dB20
12LockedQAM256531000000 Hz0.9 dBmV39.2 dB20
13LockedQAM256543000000 Hz1.6 dBmV39.7 dB10
14LockedQAM256549000000 Hz2.2 dBmV39.8 dB10
15LockedQAM256555000000 Hz2.3 dBmV39.7 dB30
16LockedQAM256561000000 Hz2.4 dBmV39.8 dB10
17LockedQAM256567000000 Hz2.2 dBmV39.7 dB00
18LockedQAM256573000000 Hz2.1 dBmV39.6 dB30
19LockedQAM256579000000 Hz2.2 dBmV39.7 dB20
20LockedQAM256585000000 Hz2.4 dBmV39.8 dB40
21LockedQAM256591000000 Hz2.3 dBmV39.7 dB10
22LockedQAM256597000000 Hz2.0 dBmV39.6 dB10
23LockedQAM256603000000 Hz1.7 dBmV38.7 dB60
24LockedQAM256609000000 Hz1.4 dBmV38.8 dB30
25LockedQAM256615000000 Hz1.4 dBmV39.3 dB00
26LockedQAM256621000000 Hz1.8 dBmV39.5 dB00
27LockedQAM256627000000 Hz2.0 dBmV39.6 dB00
28LockedQAM256633000000 Hz2.1 dBmV39.2 dB50
29LockedQAM256639000000 Hz2.8 dBmV39.6 dB50
30LockedQAM256645000000 Hz3.7 dBmV40.0 dB40
31LockedQAM256651000000 Hz5.5 dBmV40.5 dB20
32LockedQAM256657000000 Hz6.1 dBmV40.6 dB50
34LockedQAM256669000000 Hz5.0 dBmV40.2 dB140
35LockedQAM256675000000 Hz4.5 dBmV39.5 dB1018459
36LockedQAM256681000000 Hz3.8 dBmV39.9 dB386395
159LockedOther722000000 Hz2.5 dBmV36.2 dB309260
Upstream Bonded Channels
ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
12LockedSC-QAM Upstream22800000 Hz6400000 Hz36.0 dBmV
21LockedSC-QAM Upstream16400000 Hz6400000 Hz36.0 dBmV
33LockedSC-QAM Upstream29200000 Hz6400000 Hz37.0 dBmV
44LockedSC-QAM Upstream35600000 Hz6400000 Hz36.0 dBmV
55LockedSC-QAM Upstream40400000 Hz3200000 Hz34.0 dBmV

Current System Time: Tue Dec 8 15:53:15 2020

EG

Expert

 • 

87.1K Messages

6 m ago

The signal stats are in spec. Are there any error log entries being shown anywhere ? If so, please post them as well.

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Regular Visitor

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4 Messages

6 m ago

Here's what I see in the Event Log:

 

Date Time Event ID Event Level Description

12/07/2020 16:0524366940615"Dynamic Range Window violation"
12/07/2020 16:05820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=6c:63:9c:b3:b7:69;CMTS-MAC=dc:eb:94:b4:57:96;CM-QOS=1.1;CM-VER=3.1;"
12/07/2020 16:0524366940615"Dynamic Range Window violation"
12/07/2020 16:05820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=6c:63:9c:b3:b7:69;CMTS-MAC=dc:eb:94:b4:57:96;CM-QOS=1.1;CM-VER=3.1;"
12/07/2020 16:0524366940615"Dynamic Range Window violation"
12/07/2020 16:05820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=6c:63:9c:b3:b7:69;CMTS-MAC=dc:eb:94:b4:57:96;CM-QOS=1.1;CM-VER=3.1;"
12/07/2020 16:0524366940615"Dynamic Range Window violation"
12/07/2020 16:05820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=6c:63:9c:b3:b7:69;CMTS-MAC=dc:eb:94:b4:57:96;CM-QOS=1.1;CM-VER=3.1;"
01/01/1970 00:0024366940666"Honoring MDD; IP provisioning mode = IPv6"
01/01/1970 00:00840001003"SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=6c:63:9c:b3:b7:69;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
12/07/2020 16:0524366940443"Resetting the cable modem due to docsDevResetNow"
EG

Expert

 • 

87.1K Messages

6 m ago

The signal stats are o/k but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) somewhere.

 

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

 

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!tick

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