T3 Timeouts - Loss of internet access

2022-01-31, 10:51:37	Notice (6)	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=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
2022-01-31, 10:51:33	Notice (6)	CM-STATUS message sent. Event Type Code: 23; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
2022-01-31, 10:51:33	Notice (6)	CM-STATUS message sent. Event Type Code: 22; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
2022-01-31, 10:50:40	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
2022-01-31, 10:49:19	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
2022-01-31, 10:49:18	Warning (5)	MDD message timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
2022-01-31, 10:49:15	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR / MER	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	QAM256	8	399000000 Hz	7.7 dBmV	39.4 dB	3412311420	47	57
2	Locked	QAM256	4	375000000 Hz	7.1 dBmV	39.4 dB	3406753976	16	60
3	Locked	QAM256	5	381000000 Hz	7.3 dBmV	39.4 dB	1879888590	365	1040
4	Locked	QAM256	6	387000000 Hz	7.5 dBmV	39.6 dB	1879886402	282	1045
5	Locked	QAM256	7	393000000 Hz	7.8 dBmV	39.6 dB	1879902492	294	1043
6	Locked	QAM256	9	405000000 Hz	8.0 dBmV	39.5 dB	1879905718	238	1061
7	Locked	QAM256	10	411000000 Hz	8.1 dBmV	39.5 dB	1879901017	246	1049
8	Locked	QAM256	11	417000000 Hz	8.3 dBmV	39.7 dB	1879907475	251	1042
9	Locked	QAM256	12	423000000 Hz	8.1 dBmV	39.7 dB	1879919501	221	1010
10	Locked	QAM256	13	429000000 Hz	8.3 dBmV	39.6 dB	1879925062	206	1025
11	Locked	QAM256	14	435000000 Hz	8.3 dBmV	39.4 dB	1879919555	193	1047
12	Locked	QAM256	15	441000000 Hz	8.5 dBmV	39.5 dB	1879930419	209	1086
13	Locked	QAM256	16	447000000 Hz	8.6 dBmV	39.6 dB	1879925475	246	1081
14	Locked	QAM256	17	453000000 Hz	8.6 dBmV	39.7 dB	1879929896	227	1067
15	Locked	QAM256	18	459000000 Hz	8.4 dBmV	39.4 dB	1879939685	225	1061
16	Locked	QAM256	19	465000000 Hz	8.2 dBmV	39.4 dB	1879943018	240	1041
17	Locked	QAM256	20	471000000 Hz	8.0 dBmV	39.2 dB	1879956631	238	1055
18	Locked	QAM256	21	477000000 Hz	8.0 dBmV	39.3 dB	1879957859	237	1059
19	Locked	QAM256	22	483000000 Hz	7.8 dBmV	39.2 dB	1879958548	241	1071
20	Locked	QAM256	23	489000000 Hz	7.7 dBmV	39.3 dB	1879959197	231	1061
21	Locked	QAM256	24	495000000 Hz	7.6 dBmV	39.1 dB	1879963531	255	1041
22	Locked	QAM256	25	501000000 Hz	7.6 dBmV	39.1 dB	1879967803	226	1049
23	Locked	QAM256	26	507000000 Hz	7.9 dBmV	38.9 dB	1879975166	227	1040
24	Locked	QAM256	27	513000000 Hz	8.1 dBmV	39.1 dB	1879975737	231	1066
25	Locked	QAM256	28	519000000 Hz	8.2 dBmV	39.0 dB	1879978014	222	1105
26	Locked	QAM256	29	525000000 Hz	8.2 dBmV	38.9 dB	1879978593	252	1078
27	Locked	QAM256	30	531000000 Hz	8.3 dBmV	38.9 dB	1879978108	292	1085
28	Locked	QAM256	31	537000000 Hz	8.3 dBmV	38.7 dB	1879981836	273	1070
29	Locked	QAM256	32	543000000 Hz	8.2 dBmV	38.5 dB	1879980364	274	1072
30	Locked	QAM256	33	549000000 Hz	8.4 dBmV	38.6 dB	1879997244	274	1056
31	Locked	QAM256	34	555000000 Hz	8.4 dBmV	38.3 dB	1879982068	288	1057
32	Not Locked	Unknown	0	0 Hz	0.0 dBmV	0.0 dB	0	0	0

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power
1	Locked	ATDMA	1	16400000 Hz	44.5 dBmV
2	Locked	ATDMA	2	22800000 Hz	44.5 dBmV
3	Locked	ATDMA	3	29200000 Hz	45.3 dBmV
4	Locked	ATDMA	4	35600000 Hz	44.5 dBmV
5	Not Locked	Unknown	0	0 Hz	0.0 dBmV
6	Not Locked	Unknown	0	0 Hz	0.0 dBmV
7	Not Locked	Unknown	0	0 Hz	0.0 dBmV
8	Not Locked	Unknown	0	0 Hz	0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power	SNR / MER	Active Subcarrier Number Range	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	0, 1, 2, 3	48	685000000 Hz	8.5 dBmV	35.0 dB	1108 ~ 2987	4260430156	4257260179	101
2	Not Locked	0	0	0 Hz	7.0 dBmV	0.0 dB	0 ~ 4095	0	0	0

Experiencing ongoing T3 issues, resulting in loss of service and being dropped from conference calls. Any help in determining the cause would be appreciated.

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Responses

EG

Expert

•

110.2K Messages

3 years ago

Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is noise ingress into the line(s) / an upstream channel-return path impairment 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 (Cable Modem Termination System) to check 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 !

3

AntKnee00

New Poster

•

17 Messages

@EG .. Thank you for the analysis! It's greatly appreciated. This has been an ongoing issue, with the local power company out last night to confirm nothing on their end. They did confirm AC current on the coax cable going into the house. Not sure if that is causing the issue and if it is.. Where to go from here.

3 years ago

0

XfinityThomasB

Official Employee

•

1.9K Messages

Please know that our team is always here standing by ready to rock and roll to help. I know that dealing with connection hiccups can be extremely frustrating and our team is committed to providing you top notch support at all times 24/7.

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer. tick

3 years ago

0

EG

Expert

•

110.2K Messages

@XfinityThomasB

So have you polled their connection as I requested in the escalation to the team ?

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? Please mark an Accepted Answer! tick

3 years ago

0

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AntKnee00

T3 Timeouts - Loss of internet access

EG

AntKnee00

XfinityThomasB

EG

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