Intermittent connectivity and speed problems for last two weeks - T3 timeouts

[Oscar8281]

I'll go from 350mbps down and 12mbps up to completely nothing or speeds that are extraordinarily slow.  These interruptions are happening several times a day even with minimal household usage.  Please see the router stats and event logs below - I'm using an Arris SB6190 and Google Wifi mesh with three spots.  Any help would be appreciated.

Time	Priority	Description
Sat Jun 27 18:54:12 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Sat Jun 27 21:51:06 2020	5	RCS Partial Service;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 28 13:51:15 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 08:47:20 2020	3	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 08:58:24 2020	5	RCS Partial Service;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 11:23:35 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 11:35:13 2020	5	RCS Partial Service;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 11:35:13 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 11:52:59 2020	5	RCS Partial Service;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 14:32:46 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Mon Jun 29 21:19:34 2020	5	RCS Partial Service;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 08:33:15 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 11:05:26 2020	6	TLV-11 - unrecognized OID;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 11:29:44 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 11:30:28 2020	3	Ranging Request Retries exhausted;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 11:30:28 2020	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 11:30:52 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 13:13:36 2020	5	RCS Partial Service;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 13:19:42 2020	6	TLV-11 - unrecognized OID;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 30 13:47:07 2020	3	No Ranging Response received - T3 time-out;CM-MAC=5c:e3:0e:39:a0:65;CMTS-MAC=00:01:5c:96:30:6b;CM-QOS=1.1;CM-VER=3.0;

Downstream Bonded Channels
Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Corrected	Uncorrectables
1	Locked	256QAM	5	453.00 MHz	5.10 dBmV	38.61 dB	0	0
2	Locked	256QAM	6	459.00 MHz	4.80 dBmV	38.98 dB	0	0
3	Locked	256QAM	7	465.00 MHz	4.90 dBmV	38.61 dB	10	0
4	Locked	256QAM	8	471.00 MHz	4.70 dBmV	38.61 dB	14	0
5	Locked	256QAM	9	477.00 MHz	4.20 dBmV	38.61 dB	0	0
6	Locked	256QAM	10	483.00 MHz	3.70 dBmV	38.61 dB	0	0
7	Locked	256QAM	11	489.00 MHz	3.40 dBmV	38.61 dB	16	0
8	Locked	256QAM	12	495.00 MHz	3.70 dBmV	38.61 dB	14	0
9	Locked	256QAM	13	519.00 MHz	3.50 dBmV	38.98 dB	25	0
10	Locked	256QAM	14	525.00 MHz	3.00 dBmV	38.98 dB	15	0
11	Locked	256QAM	15	531.00 MHz	2.70 dBmV	38.61 dB	8	0
12	Locked	256QAM	16	537.00 MHz	2.60 dBmV	37.64 dB	5	0
13	Locked	256QAM	17	543.00 MHz	2.90 dBmV	38.61 dB	7	0
14	Locked	256QAM	18	549.00 MHz	2.60 dBmV	37.64 dB	0	0
15	Locked	256QAM	19	555.00 MHz	2.60 dBmV	38.61 dB	0	0
16	Locked	256QAM	20	561.00 MHz	3.00 dBmV	38.98 dB	14	0
17	Locked	256QAM	21	567.00 MHz	2.60 dBmV	37.64 dB	10	0
18	Locked	256QAM	22	573.00 MHz	2.90 dBmV	38.98 dB	22	0
19	Locked	256QAM	23	579.00 MHz	1.50 dBmV	38.61 dB	11	0
20	Locked	256QAM	24	585.00 MHz	2.10 dBmV	38.61 dB	0	0
21	Locked	256QAM	25	591.00 MHz	2.20 dBmV	38.61 dB	0	0
22	Locked	256QAM	26	597.00 MHz	1.90 dBmV	38.61 dB	0	0
23	Locked	256QAM	27	603.00 MHz	2.10 dBmV	37.64 dB	0	0
24	Locked	256QAM	28	609.00 MHz	2.20 dBmV	38.61 dB	0	0
25	Locked	256QAM	29	615.00 MHz	2.20 dBmV	38.20 dB	0	0
26	Locked	256QAM	30	621.00 MHz	1.90 dBmV	37.90 dB	0	0
27	Locked	256QAM	31	627.00 MHz	1.20 dBmV	38.20 dB	0	0
28	Locked	256QAM	32	633.00 MHz	1.50 dBmV	37.90 dB	0	0
29	Locked	256QAM	34	639.00 MHz	1.80 dBmV	38.20 dB	0	0
30	Locked	256QAM	35	645.00 MHz	1.20 dBmV	38.20 dB	0	0
31	Locked	256QAM	36	651.00 MHz	1.50 dBmV	38.20 dB	13	0
32	Locked	256QAM	37	657.00 MHz	1.60 dBmV	38.20 dB	19	0

Upstream Bonded Channels
Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	4	5120 kSym/s	23.70 MHz	39.75 dBmV
2	Locked	ATDMA	6	5120 kSym/s	36.50 MHz	40.75 dBmV
3	Locked	ATDMA	5	5120 kSym/s	30.10 MHz	40.25 dBmV

[EG]

For a test, does a computer hardwired directly to the 6190 modem have the same problem ? 

[Oscar8281]

I honestly don't know.  The modem and router reside in a place where I can't sit and do work waiting for the phenomenon to occur.  The drop-line from the street should be good, a tech replaced it 1.5 years ago because a squirrel chewed through it.  No splitters, only one in-line connector because previous home owner didn't have a single piece of coax long enough to reach.

[EG]

Please try that test.

[Oscar8281]

Tested.  When connected via ethernet directly to modem I get 25 down and 2 up.

[Oscar8281]

Just ran the test again and got 339 down and 12 up.  Its all over the place.

[EG]

O/k thanks. That points to it being a problem with the Comcast system / connection quality.

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 !

[ComcastAmir]

Hi Oscar8281, let's hunt down the root cause of the problem so that we can get your signals and speeds back up to par. To get started could you please send me a private message with your full name and street address by clicking on my name (ComcastAmir) and then click "Send a message"?

[Oscar8281]

Thanks.  I sent you a message.

[Oscar8281]

Just wanted to check in - I haven't heard anything.  Thank you.

[Oscar8281]

Still no resolution from Xfinity.  Here are the latest values from my modem:

Downstream Bonded Channels
Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Corrected	Uncorrectables
1	Locked	256QAM	5	453.00 MHz	5.30 dBmV	38.98 dB	1387	2580
2	Locked	256QAM	1	429.00 MHz	5.90 dBmV	38.98 dB	1676	4549
3	Locked	256QAM	2	435.00 MHz	5.80 dBmV	38.98 dB	1803	3331
4	Locked	256QAM	3	441.00 MHz	5.80 dBmV	38.61 dB	1559	4628
5	Locked	256QAM	4	447.00 MHz	5.40 dBmV	38.98 dB	1141	565
6	Locked	256QAM	6	459.00 MHz	4.80 dBmV	38.61 dB	1011	564
7	Locked	256QAM	7	465.00 MHz	5.00 dBmV	38.98 dB	1639	2475
8	Locked	256QAM	8	471.00 MHz	4.90 dBmV	38.61 dB	1095	1439
9	Locked	256QAM	9	477.00 MHz	4.60 dBmV	38.61 dB	1074	1339
10	Locked	256QAM	10	483.00 MHz	4.00 dBmV	38.98 dB	1180	1178
11	Locked	256QAM	11	489.00 MHz	3.30 dBmV	38.61 dB	1205	1305
12	Locked	256QAM	12	495.00 MHz	3.70 dBmV	38.98 dB	885	398
13	Locked	256QAM	13	519.00 MHz	3.30 dBmV	38.61 dB	945	1019
14	Locked	256QAM	14	525.00 MHz	3.10 dBmV	38.61 dB	779	1196
15	Locked	256QAM	15	531.00 MHz	2.60 dBmV	38.61 dB	960	1193
16	Locked	256QAM	16	537.00 MHz	2.20 dBmV	37.64 dB	854	146
17	Locked	256QAM	17	543.00 MHz	2.50 dBmV	38.61 dB	887	1109
18	Locked	256QAM	18	549.00 MHz	2.30 dBmV	37.64 dB	637	71
19	Locked	256QAM	19	555.00 MHz	2.60 dBmV	38.98 dB	749	1233
20	Locked	256QAM	20	561.00 MHz	2.80 dBmV	38.61 dB	1087	1931
21	Locked	256QAM	21	567.00 MHz	2.50 dBmV	38.61 dB	652	1197
22	Locked	256QAM	22	573.00 MHz	3.00 dBmV	38.61 dB	559	215
23	Locked	256QAM	23	579.00 MHz	1.30 dBmV	38.61 dB	651	77
24	Locked	256QAM	24	585.00 MHz	1.80 dBmV	38.61 dB	553	144
25	Locked	256QAM	25	591.00 MHz	2.00 dBmV	38.20 dB	587	1196
26	Locked	256QAM	26	597.00 MHz	1.80 dBmV	38.20 dB	537	1935
27	Locked	256QAM	27	603.00 MHz	2.30 dBmV	38.60 dB	618	1878
28	Locked	256QAM	28	609.00 MHz	1.70 dBmV	38.60 dB	665	1734
29	Locked	256QAM	29	615.00 MHz	2.00 dBmV	38.20 dB	619	2249
30	Locked	256QAM	30	621.00 MHz	1.70 dBmV	38.20 dB	474	1109
31	Locked	256QAM	31	627.00 MHz	0.80 dBmV	38.20 dB	681	1083
32	Locked	256QAM	32	633.00 MHz	1.20 dBmV	38.20 dB	573	360

Upstream Bonded Channels
Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	4	5120 kSym/s	23.70 MHz	42.75 dBmV
2	Locked	ATDMA	6	5120 kSym/s	36.50 MHz	42.50 dBmV
3	Locked	ATDMA	5	5120 kSym/s	30.10 MHz	43.50 dBmV

[Oscar8281]

I replied to Amir with all of the information that was requested.  I haven't received a response from Amir or from Xfinity customer support after chatting with an agent online.  This lack of customer support is unacceptable.  

[EG]

---

@Oscar8281 wrote:

I replied to Amir with all of the information that was requested.  I haven't received a response from Amir or from Xfinity customer support after chatting with an agent online.  This lack of customer support is unacceptable.  

---

I'll re-escalate this.

[Oscar8281]

The Comcast employee is suggesting that the problem is that my modem isn't getting enough airflow.  When I challenged that notion and asked what the SNR data was, his response was:

"It's minor noise in the line coming from the node, it looks like about 10 homes are impacted by this currently but with my experience with this issue it wouldn't be enough noise to cause timeouts like you're seeing. What I can do is send another signal to the modem to clear up the problem and if the issue persist then we can schedule a tech to come out to take a look on site. How does that sound?"

If 10 homes are being affected by the same noise coming from a node, that seems to rule out a problem with my modem.  It sounds more like Comcast is avoiding addressing the node issue on their end.  Thoughts?

[ComcastAmir]

I understand where you're coming from and I apologize for being so vague in my response. You have noise in the line which on my end it is showing the noise is impacting 10 homes. I do not believe the noise is causing your timeout problem because the SNR is still within spec. Think of it like a car, you may be low on gasoline but being low won't cause your car not to start or perform differently. Now if you were out of gas then that would cause the car to stall or not start. So yes you would need this issue repaired but this problem would not cause your poor speeds or disconnects. 

I sent a signal to your equipment try clear up any data blockages or noise in the line. Please test your connection for the next hour and let me know if anything changes on your end. If so we can get a tech back out to take a look.