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Multiple disconnections per day, t3 time-out and high number of uncorrectables

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Regular Visitor

Multiple disconnections per day, t3 time-out and high number of uncorrectables

I started to have multiple disconnections per day. At that point, the modem can't be accessed via http://192.68.100.1 anymore and I have to reboot to regain Internet connectivity. 

Looking at the modem after the reboot, I am seeing a lot of uncorrectables. Logs also show a fair amount of T3 time-out. This is still happening even after a tech came by and removed/added some filters to adjust the signal at the box outside the house. 

 

Any ideas?

 

Here the data from the modem about 30min after a reboot

 

Downstream Bonded Channels
Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
20LockedQAM256525000000 Hz8.7 dBmV37.4 dB6491845
17LockedQAM256507000000 Hz9.4 dBmV37.6 dB21852
18LockedQAM256513000000 Hz9.3 dBmV37.6 dB17897019
19LockedQAM256519000000 Hz9.0 dBmV37.5 dB17487064
21LockedQAM256531000000 Hz8.9 dBmV37.4 dB17687017
22LockedQAM256537000000 Hz9.1 dBmV37.5 dB17407053
23LockedQAM256543000000 Hz8.7 dBmV37.4 dB18067006
24LockedQAM256549000000 Hz8.5 dBmV37.5 dB18406952
25LockedQAM256555000000 Hz8.4 dBmV37.3 dB17617001
26LockedQAM256561000000 Hz8.7 dBmV37.2 dB17727030
27LockedQAM256567000000 Hz8.2 dBmV37.2 dB17827005
28LockedQAM256573000000 Hz7.8 dBmV37.0 dB17657008
29LockedQAM256579000000 Hz7.8 dBmV37.1 dB17317046
30LockedQAM256585000000 Hz8.1 dBmV37.1 dB17576979
31LockedQAM256591000000 Hz7.7 dBmV36.9 dB16927056
32LockedQAM256597000000 Hz7.2 dBmV36.9 dB17207023
33LockedQAM256603000000 Hz7.4 dBmV36.8 dB17317016
34LockedQAM256609000000 Hz7.5 dBmV36.9 dB18397440
35LockedQAM256615000000 Hz7.3 dBmV36.8 dB17377487
36LockedQAM256621000000 Hz6.7 dBmV36.8 dB17837476
37LockedQAM256627000000 Hz6.6 dBmV36.6 dB18337383
38LockedQAM256633000000 Hz6.8 dBmV36.6 dB18617407
39LockedQAM256639000000 Hz6.8 dBmV36.5 dB18367402
40LockedQAM256645000000 Hz6.3 dBmV36.5 dB17947445
41LockedQAM256651000000 Hz6.3 dBmV36.4 dB18477392
42LockedQAM256657000000 Hz6.4 dBmV36.6 dB18507403
43LockedQAM256663000000 Hz6.4 dBmV36.4 dB18157403
44LockedQAM256669000000 Hz5.8 dBmV36.1 dB17447473
45LockedQAM256675000000 Hz5.8 dBmV35.8 dB18647369
46LockedQAM256681000000 Hz6.2 dBmV36.4 dB18087384
47LockedQAM256687000000 Hz6.3 dBmV36.4 dB17997458
48LockedOther850000000 Hz1.7 dBmV32.5 dB136300444896


 

 
Upstream Bonded Channels
ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream30300000 Hz6400000 Hz37.0 dBmV
25LockedSC-QAM Upstream41200000 Hz1600000 Hz36.0 dBmV
32LockedSC-QAM Upstream23700000 Hz6400000 Hz37.0 dBmV
44LockedSC-QAM Upstream36700000 Hz6400000 Hz36.0 dBmV
51LockedSC-QAM Upstream17300000 Hz6400000 Hz38.0 dBmV
Highlighted
Expert

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

The stats are o/k. Please post again after 24 hours. Do no re-boot the modem. Post the error log entries as well.



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Regular Visitor

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

Here are the numbers after ~28hrs

 

Downstream Bonded Channels
Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
20LockedQAM256525000000 Hz9.4 dBmV37.5 dB2742780637
17LockedQAM256507000000 Hz10.0 dBmV37.7 dB66288229367
18LockedQAM256513000000 Hz9.9 dBmV37.7 dB71256247857
19LockedQAM256519000000 Hz9.6 dBmV37.6 dB70649244526
21LockedQAM256531000000 Hz9.6 dBmV37.5 dB71211247884
22LockedQAM256537000000 Hz9.7 dBmV37.7 dB71083246788
23LockedQAM256543000000 Hz9.3 dBmV37.5 dB71639251133
24LockedQAM256549000000 Hz9.1 dBmV37.5 dB70913248105
25LockedQAM256555000000 Hz9.0 dBmV37.3 dB70639246228
26LockedQAM256561000000 Hz9.4 dBmV37.4 dB71708249860
27LockedQAM256567000000 Hz8.9 dBmV37.2 dB70989248728
28LockedQAM256573000000 Hz8.5 dBmV37.1 dB70213249172
29LockedQAM256579000000 Hz8.5 dBmV37.2 dB70197248276
30LockedQAM256585000000 Hz8.7 dBmV37.1 dB69925248977
31LockedQAM256591000000 Hz8.4 dBmV37.0 dB69966251317
32LockedQAM256597000000 Hz7.9 dBmV37.0 dB69972250791
33LockedQAM256603000000 Hz8.1 dBmV37.0 dB69073247475
34LockedQAM256609000000 Hz8.2 dBmV37.0 dB70211249676
35LockedQAM256615000000 Hz8.0 dBmV36.8 dB69785249188
36LockedQAM256621000000 Hz7.5 dBmV36.8 dB69761250581
37LockedQAM256627000000 Hz7.3 dBmV36.7 dB69323248695
38LockedQAM256633000000 Hz7.6 dBmV36.8 dB68822250871
39LockedQAM256639000000 Hz7.5 dBmV36.7 dB69103249556
40LockedQAM256645000000 Hz7.1 dBmV36.6 dB69387252355
41LockedQAM256651000000 Hz7.0 dBmV36.6 dB69798252234
42LockedQAM256657000000 Hz7.2 dBmV36.8 dB69395251032
43LockedQAM256663000000 Hz7.2 dBmV36.5 dB69369252787
44LockedQAM256669000000 Hz6.6 dBmV36.3 dB68878250662
45LockedQAM256675000000 Hz6.6 dBmV35.9 dB69856253404
46LockedQAM256681000000 Hz6.9 dBmV36.5 dB69064248796
47LockedQAM256687000000 Hz7.0 dBmV36.4 dB69081249686
48LockedOther850000000 Hz2.6 dBmV32.2 dB80515710549542


 

 
Upstream Bonded Channels
ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream30300000 Hz6400000 Hz37.0 dBmV
25LockedSC-QAM Upstream41200000 Hz1600000 Hz36.0 dBmV
32LockedSC-QAM Upstream23700000 Hz6400000 Hz37.0 dBmV
44LockedSC-QAM Upstream36700000 Hz6400000 Hz36.0 dBmV
51LockedSC-QAM Upstream17300000 Hz6400000 Hz38.0 dBmV

 

 

Logs show the same 2 lines over and over (Modem MAC redactesd)

 

Date Time Event ID Event Level Description
10/13/2020 21:07740101006"CM-STATUS message sent. Event Type Code: 24; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1 2 3.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:01:5c:67:0a:61;CM-QOS=1.1;CM-VER=3.1;"
10/13/2020 21:07740101006"CM-STATUS message sent. Event Type Code: 16; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:01:5c:67:0a:61;CM-QOS=1.1;CM-VER=3.1;"

 

 

 

 

Highlighted
Regular Visitor

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

Note that I also have been getting a bunch of these in the recent past. Just not this time around.

 

10/11/2020 08:34

82000200

3

"No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:01:5c:67:0a:61;CM-QOS=1.1;CM-VER=3.1;"

10/11/2020 08:34

84000500

3

"SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=

xx:xx:xx:xx:xx:xx;CMTS-MAC=00:01:5c:67:0a:61;CM-QOS=1.1;CM-VER=3.1;"

Highlighted
Expert

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

The stats are o/k but there is a good amount of uncorrectable bit errors. And the error log entries confirm 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 can check the CMTS (Cable Modem Termination System) for any real time degradation and / or error reports, see your node / cable plant and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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Highlighted
Official Employee

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

Hi there, baolongnt. Thanks for reaching out to us here in the community! We appreciate you posting your modem reports as well. It's frustrating to find out you're experiencing these disconnects! I know you mentioned you've had a technician out, do you know if we have an amplifier installed at your premise?


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Regular Visitor

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

I know you mentioned you've had a technician out, do you know if we have an amplifier installed at your premise?

 

No amplifier. The tech came and unplugged all unused cables and removed some filters. Another tech came this morning and double checked all the outside wiring. Also, this time the tech came inside and checked wiring all the way to the modem. He did not find anything that would cause these issues. He replaced connectors to secure connections. Finally, he said something about creating a case to have things checked further upstream.

 

This afternoon the issue happened again. Same type of disconnect. High number of uncorrectables and same messages in the logs.

 

Highlighted
Official Employee

Re: Multiple disconnections per day, t3 time-out and high number of uncorrectables

Oh no! That's a bummer it's still happening. It sounds like the tech may have opened a maintenance request, which I can definitely check for. If you don't mind, please go ahead and send me a PM with your first and last name. We will continue from there. Thank you!

 

To send a private message, please click my name "ComcastMorgan" then select "Send a Message" on the right side.  


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Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. 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!