Question Trouble pinpointing possible issue with my internet

[Zaeke]

Hello, looking for some assistance in figuring out what could be causing some internet issues as i'm not a big networking guy.

Roughly a week ago, I noticed a severe drop in download speeds (from roughly 800mbps to 30mbps) as well as extremely varied packet latency (jumping between 20ms to 170ms all over the place) and started doing some troubleshooting. I did the usual of checking the PC connections, power cycling the modem, re-seating the connectors on the modem, and changing IPs/using a VPN to check for throttling. Of all the steps, power cycling seemed to recover some download speed but would quickly dip back to around 30mbps after 10-20 minutes. I called my ISP(Cox) to try and see if it was on their end potentially, and was told that my modem was throwing errors and that they'd send a new one.

While i've been waiting on that new modem, I did a bit of digging into both the modem's control panel, as well as the coax lines, at the behest of a friend that knows a little bit about networking. I discovered two potential problems; the modem is showing a lot of Uncorrectable Codewords in its CM Error Codeword table as well as showing some very confusing data under its Downstream Channel Value table. The second potential problem is that the coax line runs outside to a splitter (more than likely to provide a coax out port to the upper floors of our house) and it's exposed to a lot of sea air and looks fairly crusted. Below are the tables for those that can better help me interpret this.

Downstream	Channel Bonding Value
Index	21	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	22	23	24	25	26	27	28	29	30	31	32	160	159	160
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Not locked	Locked	Locked	Locked	Not locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Frequency	237 MHz	117 MHz	123 MHz	129 MHz	135 MHz	141 MHz	147 MHz	153 MHz	159 MHz	165 MHz	171 MHz	177 MHz	183 MHz	189 MHz	195 MHz	201 MHz	207 MHz	213 MHz	219 MHz	225 MHz	231 MHz	243 MHz	249 MHz	255 MHz	735 MHz	741 MHz	747 MHz	753 MHz	759 MHz	765 MHz	771 MHz	777 MHz	918 MHz	300000000	918000000
SNR	38.8 dB	0.0 dB	30.7 dB	33.3 dB	33.8 dB	34.0 dB	32.6 dB	32.7 dB	35.5 dB	35.2 dB	35.8 dB	0.0 dB	0.0 dB	0.0 dB	33.4 dB	0.0 dB	35.5 dB	36.9 dB	37.7 dB	37.9 dB	38.5 dB	38.7 dB	38.9 dB	39.2 dB	41.3 dB	41.6 dB	42.1 dB	41.5 dB	41.9 dB	40.8 dB	42.2 dB	42.3 dB	41.8 dB	40.5 dB	41.8 dB
Power Level	-14.0 dBmV	-18.4 dBmV	-17.9 dBmV	-17.5 dBmV	-17.1 dBmV	-17.1 dBmV	-17.5 dBmV	-17.7 dBmV	-16.8 dBmV	-16.4 dBmV	-16.6 dBmV	-16.6 dBmV	-17.2 dBmV	-16.8 dBmV	-15.8 dBmV	-15.3 dBmV	-15.5 dBmV	-14.9 dBmV	-14.8 dBmV	-14.7 dBmV	-14.3 dBmV	-14.1 dBmV	-14.0 dBmV	-13.3 dBmV	-6.7 dBmV	-6.8 dBmV	-6.5 dBmV	-6.4 dBmV	-6.1 dBmV	-6.4 dBmV	-6.5 dBmV	-6.1 dBmV	-4.2 dBmV	-11.4 dBmV	-4.2 dBmV
Modulation	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	Unknown	256 QAM	256 QAM	256 QAM	Unknown	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	256 QAM	OFDM	OFDM	OFDM

Upstream	Channel Bonding Value
Index	1	2	3	4	5
Lock Status	Locked	Locked	Locked	Locked	Locked
Frequency	17 MHz	23 MHz	30 MHz	36 MHz	36 MHz
Symbol Rate	5120	5120	5120	5120	0
Power Level	54.5 dBmV	54.5 dBmV	54.5 dBmV	54.0 dBmV	48.0 dBmV
Modulation	QAM	QAM	QAM	QAM	OFDMA
Channel Type	ATDMA	ATDMA	ATDMA	ATDMA	TDMA

CM Error Codewords
Index	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34
Unerrored Codewords	1972479251	2431437560	3063165197	3373375786	3374150541	3300587745	3326035817	3114249000	3020065804	3199949306	3171533606	0	3166815406	3045590408	3211027557	0	3366325277	3379482952	3379417352	3268271843	3061524235	3382717320	3382751716	3383096845	3383146262	3383150816	3383153370	3383160725	3383165227	3383166349	3383168212	3383172088	2101973990	1972479251
Correctable Codewords	1451921227	602293515	251834055	2813908	3050364	2042664	3272381	31232213	1342312	1620779	1523833	0	670441	561525	498908	0	369798	321577	299296	241593	182756	124929	133435	30807	300	282	277	242	231	218	215	284	2029660604	1451921227
Uncorrectable Codewords	9076	243631633	54874447	3508315	3522370	3038371	3461326	3763517	3035532	3518963	3070905	0	1627686	1440926	1324243	0	1077284	1007733	927575	734210	497447	287997	250828	13596	1	0	0	0	0	0	0	272	18989	9076

I've been power cycling the modem every 24 hours and checking these charts every 24 hour period and its been consistently like this for at least 3 days.

My question is what is the most probable cause? A bad modem, corroded cabling, or a fault directly with the ISP? And, what steps should I take to resolve these issues?

Thank you for taking the time to look at this, i'd appreciate any help in getting some answers.

 

[bill001g]

Signal levels are not in the recommended range. Upstream is likely the largest issue but the downstream channels are not the best and they have inconsistent values which sometime causes more issues.

This is generally some kind of cabling issue. Can be as simple as a small bit of water in some connection. It is likely outside your house but you can check the wires inside before you call the ISP

 

[dwd999]

My question is what is the most probable cause? A bad modem, corroded cabling, or a fault directly with the ISP? And, what steps should I take to resolve these issues?

Thank you for taking the time to look at this, i'd appreciate any help in getting some answers.

Don't allow Cox to be so lazy. Insist that they send a service person to your house.