CAX30s Xfinity 1G speed issues

Aspirant

Dec 07, 2023

This is on a cat 8 ethernet wired. Firmware version 1.4.12.2. I had upgraded firmware to the latest when i first got the CAX30 but the speeds were terrible so I came back down to 1.4.12.2 and hadn't had any issues until today

Time	Priority	Description
2023-12-07 18:14:56	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2023-12-07 17:43:57	Error (4)	SW upgrade Failed before download -TFTP Max Retry Exceeded
2023-12-07 17:43:27	Notice (6)	SW Download INIT - Via Config file d11_m_cax30_extremepro_c01.cm
2023-12-07 17:43:16	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile:
1970-01-01 00:00:41	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
1970-01-01 00:00:35	Critical (3)	No Ranging Response received - T3 time-out;CM-
1970-01-01 00:00:29	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2023-12-07 17:41:28	Critical (3)	Resetting the cable modem due to docsDevResetNow
1970-01-01 00:00:30	Critical (3)	No Ranging Response received - T3 time-out
1970-01-01 00:00:24	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
1970-01-01 00:00:29	Critical (3)	No Ranging Response received - T3 time-out;CM-
1970-01-01 00:00:24	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2023-12-07 16:23:15	Critical (3)	Resetting the cable modem due to docsDevResetNow

Frequency start Value

This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.

Starting Frequency

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

Procedure	Status	Comment
Acquire Downstream Channel	705000000 Hz	Locked
Connectivity State	OK	Registration Complete
Boot State	OK	Operational
Security	Enabled	BPI+
IP Provisioning Mode	Honor MDD	IPv6 only

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

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectabables
1	Locked	256 QAM	37	705000000 Hz	-4.-8 dBmV	38.0 dB	183616	172984
2	Locked	256 QAM	10	531000000 Hz	-3.-3 dBmV	41.4 dB	0	0
3	Locked	256 QAM	11	537000000 Hz	-3.-4 dBmV	41.5 dB	0	0
4	Locked	256 QAM	12	543000000 Hz	-2.-5 dBmV	42.0 dB	0	0
5	Locked	256 QAM	13	549000000 Hz	-2.-8 dBmV	42.0 dB	0	0
6	Locked	256 QAM	14	555000000 Hz	-3.-1 dBmV	42.1 dB	0	0
7	Locked	256 QAM	15	561000000 Hz	-2.-2 dBmV	42.5 dB	0	0
8	Locked	256 QAM	16	579000000 Hz	-2.-4 dBmV	42.7 dB	0	0
9	Locked	256 QAM	17	585000000 Hz	-2.-3 dBmV	42.7 dB	0	0
10	Locked	256 QAM	18	591000000 Hz	-3.-6 dBmV	42.1 dB	0	0
11	Locked	256 QAM	19	597000000 Hz	-3.-8 dBmV	42.1 dB	0	0
12	Locked	256 QAM	20	603000000 Hz	-3.-9 dBmV	41.8 dB	0	0
13	Locked	256 QAM	21	609000000 Hz	-4.-8 dBmV	41.4 dB	0	0
14	Locked	256 QAM	22	615000000 Hz	-4.-7 dBmV	41.2 dB	0	0
15	Locked	256 QAM	23	621000000 Hz	-3.-6 dBmV	41.3 dB	0	0
16	Locked	256 QAM	24	627000000 Hz	-4.0 dBmV	40.8 dB	0	0
17	Locked	256 QAM	25	633000000 Hz	-4.-4 dBmV	40.5 dB	0	0
18	Locked	256 QAM	26	639000000 Hz	-3.-8 dBmV	40.3 dB	0	0
19	Locked	256 QAM	27	645000000 Hz	-3.-7 dBmV	39.9 dB	0	0
20	Locked	256 QAM	28	651000000 Hz	-3.-7 dBmV	39.9 dB	0	0
21	Locked	256 QAM	29	657000000 Hz	-3.0 dBmV	39.9 dB	0	0
22	Locked	256 QAM	30	663000000 Hz	-3.0 dBmV	39.8 dB	0	0
23	Locked	256 QAM	31	669000000 Hz	-3.-6 dBmV	39.6 dB	0	0
24	Locked	256 QAM	32	675000000 Hz	-3.-5 dBmV	39.4 dB	0	0
25	Locked	256 QAM	33	681000000 Hz	-3.-8 dBmV	39.6 dB	0	0
26	Locked	256 QAM	34	687000000 Hz	-4.-9 dBmV	39.3 dB	0	0
27	Locked	256 QAM	35	693000000 Hz	-5.-1 dBmV	39.2 dB	0	0
28	Locked	256 QAM	36	699000000 Hz	-4.-6 dBmV	39.1 dB	0	0
29	Locked	256 QAM	38	711000000 Hz	-4.-9 dBmV	38.9 dB	46474	49181
30	Locked	256 QAM	39	717000000 Hz	-4.-6 dBmV	39.0 dB	0	0
31	Locked	256 QAM	40	723000000 Hz	-4.-7 dBmV	39.0 dB	0	0
32	Not Locked	Unknown	0	0 Hz	0.0 dBmV	0.0 dB	0	0

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

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	1	5120 Ksym/sec	35600000 Hz	55.3 dBmV
2	Locked	ATDMA	2	5120 Ksym/sec	29200000 Hz	54.5 dBmV
3	Locked	ATDMA	3	5120 Ksym/sec	22800000 Hz	53.0 dBmV
4	Locked	ATDMA	4	5120 Ksym/sec	16400000 Hz	51.8 dBmV
5	Locked	ATDMA	5	5120 Ksym/sec	39600000 Hz	52.8 dBmV
6	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV
7	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV
8	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV

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

Channel	Channel ID	Indicator	Subcarrier Zero Frequency	Active Subcarrier Number Range	Total Codewords	Uncorrectable Codewords
1	41	Non-Primary	671.6 MHz	1108 ~ 2987	10975123	0
2	0	Other	0 MHz	0 ~ 0	0	0

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

Channel	UpstreamIsMuted	Ranging Status	Subcarrier Zero Frequency	Active Subcarrier Number Range	Symbols Per Frame	Tx Power
1		Other	0 MHz	0 ~ 0	0	0 dBmV
2		Other	0 MHz	0 ~ 0	0	0 dBmV

FURRYe38

Guru - Experienced User

Dec 07, 2023

Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.

Power is on the low side but with specs:

https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router

There's lots of uncorrecables and correctables on one channel that should be zeros like the other channels.

I'd re-update FW back to suggested. Then have the ISP take a look at what has been put forth here.

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
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
https://highspeed.tips/docsis-events/

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