CM700 dropping internet, xfinity claims cable OK

My CM700 is dropping internet regularly and a reboot of the modem generally recovers from the problem the quickest. The following is a log snippet that is representative of the whole event log: T...

Hardware

Troubleshooting

FURRYe38

Guru - Experienced User

Jan 30, 2023

You have Criticals and Warnings that the ISP needs to review and resolve from there side.

Please post a copy and paste of the modems connection status and event log page.
https://kb.netgear.com/30007/How-do-I-obtain-the-cable-connection-information-from-a-NETGEAR-cable-modem-modem-router

Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended.
What is the brand and model of the host wifi router connected to the modem?

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure to power OFF the modem for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

yekiMikey

Aspirant

Jan 30, 2023

I am using a tp-link deco ac1200 router. Xfinity claims the cables on their side are OK.

<tabindex=-1>Startup Procedure</tabindex=-1>

Procedure	Status	Comment
Acquire Downstream Channel	411000000 Hz	Locked
Connectivity State	Ok	Operational
Boot State	Ok	Operational
Security	Enabled	BPI+
IP Provisioning Mode	Honor MDD	honorMdd(4)

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	UnCorrectables
1	Locked	QAM 256	1	387000000 Hz	3.0 dBmV	37.3 dB	0	0
2	Locked	QAM 256	2	393000000 Hz	3.0 dBmV	37.3 dB	0	0
3	Locked	QAM 256	3	399000000 Hz	3.0 dBmV	37.3 dB	0	0
4	Locked	QAM 256	4	405000000 Hz	3.0 dBmV	36.6 dB	0	0
5	Locked	QAM 256	5	411000000 Hz	3.2 dBmV	36.3 dB	0	0
6	Locked	QAM 256	6	417000000 Hz	3.2 dBmV	36.6 dB	0	0
7	Locked	QAM 256	7	423000000 Hz	3.0 dBmV	37.3 dB	0	0
8	Locked	QAM 256	8	429000000 Hz	3.0 dBmV	37.3 dB	0	0
9	Locked	QAM 256	9	435000000 Hz	3.0 dBmV	36.6 dB	0	0
10	Locked	QAM 256	10	441000000 Hz	3.0 dBmV	37.3 dB	0	0
11	Locked	QAM 256	11	447000000 Hz	3.0 dBmV	37.3 dB	0	0
12	Locked	QAM 256	12	453000000 Hz	3.0 dBmV	36.6 dB	0	1
13	Locked	QAM 256	13	459000000 Hz	3.2 dBmV	36.6 dB	0	0
14	Locked	QAM 256	14	465000000 Hz	3.0 dBmV	36.6 dB	23	0
15	Locked	QAM 256	15	471000000 Hz	3.2 dBmV	37.3 dB	0	0
16	Locked	QAM 256	16	477000000 Hz	3.4 dBmV	37.3 dB	7	0
17	Locked	QAM 256	17	483000000 Hz	3.5 dBmV	37.3 dB	0	0
18	Locked	QAM 256	18	489000000 Hz	3.7 dBmV	36.3 dB	4	0
19	Locked	QAM 256	19	495000000 Hz	3.7 dBmV	37.3 dB	7	0
20	Locked	QAM 256	20	507000000 Hz	4.0 dBmV	37.3 dB	0	0
21	Locked	QAM 256	21	513000000 Hz	3.9 dBmV	37.6 dB	0	0
22	Locked	QAM 256	22	519000000 Hz	4.0 dBmV	37.6 dB	0	0
23	Locked	QAM 256	23	525000000 Hz	4.1 dBmV	37.3 dB	0	0
24	Locked	QAM 256	24	531000000 Hz	4.5 dBmV	37.3 dB	16	0
25	Locked	QAM 256	25	537000000 Hz	4.4 dBmV	37.3 dB	7	0
26	Locked	QAM 256	26	543000000 Hz	4.4 dBmV	37.3 dB	1725	0
27	Locked	QAM 256	27	555000000 Hz	4.5 dBmV	36.9 dB	97	625
28	Locked	QAM 256	28	561000000 Hz	4.5 dBmV	36.9 dB	10	0
29	Locked	QAM 256	29	567000000 Hz	4.8 dBmV	37.3 dB	18	0
30	Locked	QAM 256	30	573000000 Hz	4.9 dBmV	37.6 dB	0	0
31	Locked	QAM 256	31	579000000 Hz	4.9 dBmV	37.6 dB	0	0
32	Locked	QAM 256	32	585000000 Hz	5.0 dBmV	37.9 dB	0	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	8	5120 Ksym/sec	16400000 Hz	44.5 dBmV
2	Locked	ATDMA	7	5120 Ksym/sec	22800000 Hz	44.8 dBmV
3	Locked	ATDMA	6	5120 Ksym/sec	29200000 Hz	44.8 dBmV
4	Locked	ATDMA	5	5120 Ksym/sec	35600000 Hz	44.5 dBmV
5	Locked	ATDMA	10	1280 Ksym/sec	39600000 Hz	41.5 dBmV
6	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
7	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
8	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV

yekiMikey
Aspirant
Jan 30, 2023
I also found my cm700 on the "bad modems" page, I'm wondering if it could be that...
FURRYe38
Guru - Experienced User
Jan 30, 2023
Well power levels are good. There a a few Correct and Un-correctables that could be/should be zeros, however don't think those would be a real cause.

Ya the CM700 is a Intel Puma based chipset modem and was on a list that came from DSLReports site.
You could try a different modem, the CM1000, 1100 and 1200 are Broadcom based modems are not effected by the Intel vulnerability. Might try a different modem to see if the problem follows.
- yekiMikey
  Aspirant
  Jan 30, 2023
  Sounds good, I will try that, thank you for the assistance!
  - FURRYe38
    Guru - Experienced User
    Jan 30, 2023
    👍

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CM700 dropping internet, xfinity claims cable OK