[SOLVED] Periodic Drops in Internet Connection

[TheBigFunk]

Router: Netgear Nighthawk r7000
Modem: Motorola 24x8, Model MB7621
ISP/Connection Type: Xfinity broadband (175mbps).
Devices Connected: We have 12 items in total connected to our router. 3 on the 2.4GHz . 7 on 5GHz. And 2 that are wired. I've attempted to plug directly into the router with the same issue. 5 computers are connected to our router. (2 work, 3 personal).

Anytime the internet goes down, we remain connected to our Wifi/Router, but receive a 'Connection Refused' message when we try to navigate the web. Our work laptops, which connect to our router/modem, but use a VPN, have been completely unaffected during these periodic drops.

I don't have any switches, and have swapped out the Coaxial cable, plugged directly into the Modem, and still receive the same issue. The times that it drops are seemingly random throughout the day, and can be for under a minute, or up to 30 minutes. Looking at the Error log on our Router I'm seeing a lot of T3 and T4 Errors. Posted the log below. I've checked - and our router also has the most recent Firmware installed.

I've been talking to Xfinity customer service, but they keep pushing their rentable router as a potential solution, and there is a tech coming out this upcoming weekend - but I just want to know, what would cause these issues?

Error Log:

Time	Priority	Description
Wed Apr 21 12:50:53 2021	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Thu Apr 22 00:57:11 2021	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Thu Apr 22 00:57:21 2021	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Wed May 26 00:19:46 2021	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Wed Jun 16 06:44:47 2021	Critical (3)	Resetting the cable modem due to docsDevResetNow
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Wed Jun 16 06:44:13 2021	Critical (3)	Resetting the cable modem due to docsDevResetNow
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Fri Jun 18 17:51:18 2021	Critical (3)	Resetting the cable modem due to docsDevResetNow
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Sat Jun 19 09:53:38 2021	Critical (3)	Resetting the cable modem due to docsDevResetNow
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Sun Jun 20 13:09:33 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:10:34 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:10:34 2021	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:10:55 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:10:55 2021	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:15 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:15 2021	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:35 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:35 2021	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:55 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:55 2021	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 20 13:11:57 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Sun Jun 20 13:14:44 2021	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Tue Jun 22 19:23:27 2021	Critical (3)	Resetting the cable modem due to docsDevResetNow
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Wed Jun 23 02:12:12 2021	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.1;CM-VER=3.0;
Wed Jun 23 18:08:31 2021	Critical (3)	Resetting the cable modem due to docsDevResetNow
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=00:40:36:70:e1:99;CMTS-MAC=00🇨🇨fc:60:37:21;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6

Downstream Bonded Channels:

[TD] Channel[/TD]
[TD]Lock Status[/TD]
[TD]Modulation[/TD]
[TD]Channel ID[/TD]
[TD]Freq. (MHz)[/TD]
[TD]Pwr (dBmV)[/TD]
[TD]SNR (dB)[/TD]
[TD]Corrected[/TD]
[TD]Uncorrected[/TD]​

[TD]1[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]17[/TD]
[TD]525.0[/TD]
[TD]2.5[/TD]
[TD]36.9[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]2[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]21[/TD]
[TD]549.0[/TD]
[TD]3.0[/TD]
[TD]37.0[/TD]
[TD]2[/TD]
[TD]0[/TD]​

[TD]3[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]22[/TD]
[TD]555.0[/TD]
[TD]3.0[/TD]
[TD]37.0[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]4[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]23[/TD]
[TD]561.0[/TD]
[TD]3.2[/TD]
[TD]37.0[/TD]
[TD]3[/TD]
[TD]0[/TD]​

[TD]5[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]24[/TD]
[TD]567.0[/TD]
[TD]3.4[/TD]
[TD]37.0[/TD]
[TD]5[/TD]
[TD]0[/TD]​

[TD]6[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]1[/TD]
[TD]411.0[/TD]
[TD]0.1[/TD]
[TD]36.9[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]7[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]2[/TD]
[TD]417.0[/TD]
[TD]0.3[/TD]
[TD]36.9[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]8[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]3[/TD]
[TD]423.0[/TD]
[TD]0.6[/TD]
[TD]37.0[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]9[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]4[/TD]
[TD]435.0[/TD]
[TD]1.4[/TD]
[TD]37.1[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]10[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]5[/TD]
[TD]447.0[/TD]
[TD]1.6[/TD]
[TD]37.1[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]11[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]6[/TD]
[TD]453.0[/TD]
[TD]1.6[/TD]
[TD]37.1[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]12[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]7[/TD]
[TD]459.0[/TD]
[TD]1.6[/TD]
[TD]37.0[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]13[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]8[/TD]
[TD]465.0[/TD]
[TD]1.8[/TD]
[TD]37.1[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]14[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]9[/TD]
[TD]471.0[/TD]
[TD]2.1[/TD]
[TD]37.2[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]15[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]10[/TD]
[TD]477.0[/TD]
[TD]2.0[/TD]
[TD]37.2[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]16[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]11[/TD]
[TD]483.0[/TD]
[TD]1.9[/TD]
[TD]37.2[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]17[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]12[/TD]
[TD]489.0[/TD]
[TD]1.7[/TD]
[TD]37.8[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]18[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]13[/TD]
[TD]495.0[/TD]
[TD]1.7[/TD]
[TD]37.6[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]19[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]14[/TD]
[TD]507.0[/TD]
[TD]2.0[/TD]
[TD]37.7[/TD]
[TD]1[/TD]
[TD]0[/TD]​

[TD]20[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]15[/TD]
[TD]513.0[/TD]
[TD]1.9[/TD]
[TD]37.7[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]21[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]16[/TD]
[TD]519.0[/TD]
[TD]1.8[/TD]
[TD]36.8[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]22[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]18[/TD]
[TD]531.0[/TD]
[TD]2.4[/TD]
[TD]36.8[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]23[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]19[/TD]
[TD]537.0[/TD]
[TD]2.6[/TD]
[TD]35.2[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]24[/TD]
[TD]Locked[/TD]
[TD]QAM256[/TD]
[TD]20[/TD]
[TD]543.0[/TD]
[TD]2.5[/TD]
[TD]36.7[/TD]
[TD]0[/TD]
[TD]0[/TD]​

[TD]Total[/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD]11[/TD]
[TD]0[/TD]​

Upstream Bonded Channels:

[TD] Channel[/TD]
[TD]Lock Status[/TD]
[TD]Channel Type[/TD]
[TD]Channel ID[/TD]
[TD]Symb. Rate (Ksym/sec)[/TD]
[TD]Freq. (MHz)[/TD]
[TD]Pwr (dBmV)[/TD]​

[TD]1[/TD]
[TD]Locked[/TD]
[TD]ATDMA[/TD]
[TD]5[/TD]
[TD]2560[/TD]
[TD]40.4[/TD]
[TD]42.5[/TD]​

[TD]2[/TD]
[TD]Locked[/TD]
[TD]ATDMA[/TD]
[TD]1[/TD]
[TD]5120[/TD]
[TD]16.4[/TD]
[TD]45.4[/TD]​

[TD]3[/TD]
[TD]Locked[/TD]
[TD]ATDMA[/TD]
[TD]2[/TD]
[TD]5120[/TD]
[TD]22.8[/TD]
[TD]45.0[/TD]​

[TD]4[/TD]
[TD]Locked[/TD]
[TD]ATDMA[/TD]
[TD]3[/TD]
[TD]5120[/TD]
[TD]29.2[/TD]
[TD]44.3[/TD]​

[TD]5[/TD]
[TD]Locked[/TD]
[TD]ATDMA[/TD]
[TD]4[/TD]
[TD]5120[/TD]
[TD]35.6[/TD]
[TD]43.9[/TD]​

[TD]6[/TD]
[TD]Not Locked[/TD]
[TD]Unknown[/TD]
[TD]0[/TD]
[TD]0[/TD]
[TD]0[/TD]
[TD]0.0[/TD]​

[TD]7[/TD]
[TD]Not Locked[/TD]
[TD]Unknown[/TD]
[TD]0[/TD]
[TD]0[/TD]
[TD]0[/TD]
[TD]0.0[/TD]​

[TD]8[/TD]
[TD]Not Locked[/TD]
[TD]Unknown[/TD]
[TD]0[/TD]
[TD]0[/TD]
[TD]0[/TD]
[TD]0.0[/TD]​

Thank you!

 

[bill001g]

That sure did not cut and paste well. Check the values with one of sites that has the recommended signals levels. It varies a bit based on the encoding. I think it is ok but it is extremely hard to tell.

SYNC errors are almost always the ISP equipment problem. The reset message is the ISP equipment telling your modem to reboot/train.

My guess is this is not a problem with your modem but it might be.

Call the ISP they can see these messages and they should also be able to see messages from their equipment that may tell more about why for example it sends you a reset.

 

[TheBigFunk]

That sure did not cut and paste well. Check the values with one of sites that has the recommended signals levels. It varies a bit based on the encoding. I think it is ok but it is extremely hard to tell.

SYNC errors are almost always the ISP equipment problem. The reset message is the ISP equipment telling your modem to reboot/train.

My guess is this is not a problem with your modem but it might be.

Call the ISP they can see these messages and they should also be able to see messages from their equipment that may tell more about why for example it sends you a reset.

v


Oh boy - sorry about that, didn't catch that those didn't paste over well.

I'll check the recommended signal levels.


Here's the Downstream:

Channel	Lock Status	Modulation	Channel ID	Freq. (MHz)	Pwr (dBmV)	SNR (dB)	Corrected	Uncorrected
1	Locked	QAM256	17	525.0	2.5	37.3	1	0
2	Locked	QAM256	21	549.0	2.9	37.4	4	0
3	Locked	QAM256	22	555.0	3.0	37.4	2	0
4	Locked	QAM256	23	561.0	3.2	37.4	4	0
5	Locked	QAM256	24	567.0	3.4	37.4	6	0
6	Locked	QAM256	1	411.0	-0.2	37.2	0	0
7	Locked	QAM256	2	417.0	0.0	37.3	0	0
8	Locked	QAM256	3	423.0	0.5	37.5	0	0
9	Locked	QAM256	4	435.0	1.4	37.7	0	0
10	Locked	QAM256	5	447.0	1.6	37.6	0	0
11	Locked	QAM256	6	453.0	1.5	37.6	0	0
12	Locked	QAM256	7	459.0	1.6	37.6	0	0
13	Locked	QAM256	8	465.0	1.8	37.6	0	0
14	Locked	QAM256	9	471.0	2.1	37.7	0	0
15	Locked	QAM256	10	477.0	2.1	37.7	0	0
16	Locked	QAM256	11	483.0	2.0	37.7	0	0
17	Locked	QAM256	12	489.0	1.8	38.3	0	0
18	Locked	QAM256	13	495.0	1.8	38.2	0	0
19	Locked	QAM256	14	507.0	2.1	38.3	1	0
20	Locked	QAM256	15	513.0	2.1	38.1	0	0
21	Locked	QAM256	16	519.0	1.9	37.2	0	0
22	Locked	QAM256	18	531.0	2.4	37.1	0	0
23	Locked	QAM256	19	537.0	2.7	36.2	0	0
24	Locked	QAM256	20	543.0	2.6	37.3	1	0
Total							19	0

Upstream:

Channel	Lock Status	Channel Type	Channel ID	Symb. Rate (Ksym/sec)	Freq. (MHz)	Pwr (dBmV)
1	Locked	ATDMA	5	2560	40.4	42.5
2	Locked	ATDMA	1	5120	16.4	45.4
3	Locked	ATDMA	2	5120	22.8	45.0
4	Locked	ATDMA	3	5120	29.2	44.3
5	Locked	ATDMA	4	5120	35.6	43.9
6	Not Locked	Unknown	0	0	0	0.0
7	Not Locked	Unknown	0	0	0	0.0
8	Not Locked	Unknown	0	0	0	0.0

 

[bill001g]

That is a lot better. Those numbers are very good. You also see almost no error packet then again it depends on how log it was since it reset.

This almost has to be a ISP issue.

 

[TheBigFunk]

That is a lot better. Those numbers are very good. You also see almost no error packet then again it depends on how log it was since it reset.

This almost has to be a ISP issue.

Thank you for taking a look at those numbers!