Connectivity instability, low speed, Power and SNR look out of spec

Question

Hi there,

First, I have had reliable fast internet for years from xfinity. Prior to 2-3 weeks ago I was consistently able to get ~900Mb down and ~41Mb up on most speed tests. It was awesome!

The last few weeks I am running into issues with dropped connections at the WAN, and much slower bandwidth.

Equipment / config:

Netgear CM1150v (Firmware v04.02.02)

Coax connection, 1 splitter as the line enters the house. 2-way, -3.5dB

CAT 6e on all wired connections on equipment. Cable Modem to Router to Wired devices.

802.11ax on PC/iPad wireless connections

Details:

Wired Speedtest down: ~250Mb

Wired Speedtest up: ~39Mb

Ping / Packet Loss (looks ok)

Ping statistics for 172.217.14.206: (Google.com)
Packets: Sent = 114, Received = 114, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 9ms, Maximum = 44ms, Average = 16ms

Here are the cable modem details after factory reset and 1 hour of uptime. This is where I believe the issues are.

Downstream Power / SNR not great.

Upstream Power is low.

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	627000000 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	QAM256	33	627000000 Hz	11.3 dBmV	35.8 dB	2240	0
2	Locked	QAM256	13	495000000 Hz	13.5 dBmV	37.2 dB	63	0
3	Locked	QAM256	14	507000000 Hz	13.4 dBmV	37.1 dB	116	0
4	Locked	QAM256	15	513000000 Hz	13.3 dBmV	36.9 dB	168	0
5	Locked	QAM256	16	519000000 Hz	13.1 dBmV	37 dB	139	0
6	Locked	QAM256	17	525000000 Hz	13 dBmV	36.9 dB	179	0
7	Locked	QAM256	18	531000000 Hz	12.8 dBmV	36.8 dB	277	0
8	Locked	QAM256	19	543000000 Hz	12.6 dBmV	36.7 dB	305	0
9	Locked	QAM256	20	549000000 Hz	12.4 dBmV	36.6 dB	368	0
10	Locked	QAM256	21	555000000 Hz	12.6 dBmV	36.6 dB	464	0
11	Locked	QAM256	22	561000000 Hz	12.7 dBmV	36.7 dB	500	0
12	Locked	QAM256	23	567000000 Hz	12.4 dBmV	36.6 dB	611	0
13	Locked	QAM256	24	573000000 Hz	12.4 dBmV	36.6 dB	778	437
14	Locked	QAM256	25	579000000 Hz	12.5 dBmV	36.6 dB	796	445
15	Locked	QAM256	26	585000000 Hz	12.2 dBmV	36.4 dB	1013	464
16	Locked	QAM256	27	591000000 Hz	11.8 dBmV	36.3 dB	1193	196
17	Locked	QAM256	28	597000000 Hz	11.9 dBmV	36.3 dB	1268	467
18	Locked	QAM256	29	603000000 Hz	12.1 dBmV	36.3 dB	1320	448
19	Locked	QAM256	30	609000000 Hz	11.7 dBmV	36.2 dB	1547	447
20	Locked	QAM256	31	615000000 Hz	11.5 dBmV	36.1 dB	1467	462
21	Locked	QAM256	32	621000000 Hz	11.4 dBmV	35.9 dB	1853	468
22	Locked	QAM256	34	633000000 Hz	10.9 dBmV	35.6 dB	3180	480
23	Locked	QAM256	35	639000000 Hz	10.6 dBmV	35.6 dB	3180	486
24	Locked	QAM256	36	645000000 Hz	10.6 dBmV	35.6 dB	2931	485
25	Locked	QAM256	37	651000000 Hz	10.7 dBmV	35.5 dB	3274	493
26	Locked	QAM256	38	657000000 Hz	10.5 dBmV	35.4 dB	4327	1157
27	Locked	QAM256	39	663000000 Hz	10.5 dBmV	35.4 dB	3982	1139
28	Locked	QAM256	40	669000000 Hz	10.4 dBmV	35.3 dB	4542	1140
29	Locked	QAM256	41	675000000 Hz	10.4 dBmV	35.1 dB	3919	1147
30	Locked	QAM256	42	681000000 Hz	10.2 dBmV	35.3 dB	4642	1219
31	Locked	QAM256	43	687000000 Hz	10.4 dBmV	35.3 dB	4484	1104
32	Locked	QAM256	44	693000000 Hz	10.3 dBmV	35.2 dB	4338	1097

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	1	5120 Ksym/sec	17300000 Hz	26.3 dBmV
2	Locked	ATDMA	2	5120 Ksym/sec	23700000 Hz	27.3 dBmV
3	Locked	ATDMA	3	5120 Ksym/sec	30100000 Hz	27.3 dBmV
4	Locked	ATDMA	4	5120 Ksym/sec	36500000 Hz	27.8 dBmV
5	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
6	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
7	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
8	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV

Downstream OFDM Channels

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	159	722000000 Hz	9.6 dBmV	35.2 dB	1246 ~ 2849	146581876	37864453	2285
2	Not Locked	0	0	0 Hz	0 dBmV	0.0 dB	0 ~ 4095	0	0	0

Upstream OFDMA Channels

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power
1	Not Locked	0	0	0 Hz	0 dBmV
2	Not Locked	0	0	0 Hz	0 dBmV

Time	Priority	Description
Thu Nov 12 07:33:23 2020	Notice (6)	CM-STATUS message sent. Event Type Code: 5; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;
Thu Nov 12 07:33:15 2020	Warning (5)	REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;
Thu Nov 12 07:33:11 2020	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;
Thu Nov 12 07:33:10 2020	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;
Thu Nov 12 07:32:59 2020	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
Thu Nov 12 07:32:43 2020	Warning (5)	DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;
Thu Nov 12 07:32:33 2020	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;
Thu Nov 12 07:32:06 2020	Warning (5)	MDD message timeout;CM-MAC=28:80:88:d1:6d:60;CMTS-MAC=00:42:5a:1d:8f:24;CM-QOS=1.1;CM-VER=3.1;

All help and advice appreciated. Thx!

Your Home Network

Level50Jerk

Connectivity instability, low speed, Power and SNR look out of spec

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