Internet goes out several times a day. Upstream channels not locked when it happens.

Hi,

I got xfinity last Thursday, and it goes down several times a day for a few minutes. I think it's related to upstream power levels, because when it's down, those are high and some upstream channels show as not locked. I've tried a lot of things (please don't tell me to reboot the modem again), and to simplify the situation as much as possible I bypassed everything and just have the comcast-provided coax cable that came with the modem plugged directly into the coax line coming in from the street. All connections are as firm as I can get them. On the other side of the modem I have an ethernet cable plugged directly into a laptop.

I set up a script to ping the modem (10.0.0.1), the WAN gateway, and comcast.net every minute. 10.0.0.1 is always reachable. When the internet is down I get 100% packet loss to the WAN gateway and comcast.net.

When it's down, I get stats like this:

XFINITY Network

Internet:Active

Local time:2021-07-11 17:34:43

System Uptime:0 days 10h: 4m: 31s

WAN IP Address (IPv4):

WAN Default Gateway Address (IPv4):73.222.152.1

WAN IP Address (IPv6):

WAN Default Gateway Address (IPv6):

Delegated prefix (IPv6):

Primary DNS Server (IPv4):75.75.75.75

Secondary DNS Server (IPv4):75.75.76.76

Primary DNS Server (IPv6):2001:558:feed::1

Secondary DNS Server (IPv6):2001:558:feed::2

WAN Link Local Address (IPv6):

DHCP Client (IPv4):Enabled

DHCP Client (IPv6):Enabled

DHCP Lease Expire Time (IPv4):2d:19h:34m

DHCP Lease Expire Time (IPv6):0d:0h:0m

WAN MAC:

eMTA MAC:[Edited: "Personal Information"]

CM MAC:[Edited: "Personal Information"]

Initialization Procedure

Initialize Hardware:Complete

Acquire Downstream Channel:Complete

Upstream Ranging:Complete

DHCP bound:Complete

Set Time-of-Day:Complete

Configuration File Download:Complete

Registration:Complete

Cable Modem

HW Version:2.0

Vendor:Technicolor

BOOT Version:S1TC-3.63.20.104

Core Version:1.0

Model:CGM4331COM

Product Type:XB7

Flash Part:8192 MB

Download Version:Prod_20.2_d31 & Prod_20.2

Serial Number:304930041131106155

Downstream	Channel Bonding Value
Index	20	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	21	22	23	24	25	26	27	28	29	30	31	32	33	34	48
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Frequency	513 MHz	405 MHz	411 MHz	417 MHz	423 MHz	429 MHz	435 MHz	441 MHz	453 MHz	459 MHz	465 MHz	471 MHz	477 MHz	483 MHz	489 MHz	495 MHz	507 MHz	519 MHz	525 MHz	531 MHz	543 MHz	549 MHz	555 MHz	561 MHz	567 MHz	573 MHz	579 MHz	585 MHz	591 MHz	597 MHz	603 MHz	688000000
SNR	42.9 dB	42.8 dB	42.9 dB	42.8 dB	42.7 dB	42.7 dB	42.8 dB	42.9 dB	42.6 dB	42.8 dB	42.8 dB	42.7 dB	42.7 dB	42.7 dB	42.7 dB	42.8 dB	42.8 dB	42.7 dB	42.5 dB	42.4 dB	42.6 dB	42.6 dB	42.4 dB	42.3 dB	42.2 dB	42.1 dB	42.2 dB	42.3 dB	42.3 dB	42.2 dB	42.0 dB	NA
Power Level	-1.1 dBmV	-2.0 dBmV	-1.9 dBmV	-1.9 dBmV	-2.0 dBmV	-2.0 dBmV	-1.9 dBmV	-1.8 dBmV	-1.6 dBmV	-1.5 dBmV	-1.3 dBmV	-1.2 dBmV	-1.1 dBmV	-1.3 dBmV	-1.4 dBmV	-1.4 dBmV	-1.1 dBmV	-1.4 dBmV	-1.9 dBmV	-2.2 dBmV	-1.8 dBmV	-1.6 dBmV	-1.9 dBmV	-2.5 dBmV	-2.5 dBmV	-2.4 dBmV	-1.8 dBmV	-1.4 dBmV	-1.4 dBmV	-1.7 dBmV	-2.2 dBmV	NA
Modulation	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	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

Upstream	Channel Bonding Value
Index	1	2	3	4	5
Lock Status	Locked	Not Locked	Not Locked	Not Locked	Not Locked
Frequency	17 MHz	23 MHz	30 MHz	36 MHz	41 MHz
Symbol Rate	5120	5120	5120	5120	1280
Power Level	47.3 dBmV	55.0 dBmV	52.0 dBmV	50.5 dBmV	46.8 dBmV
Modulation	QAM	QAM	QAM	QAM	QAM
Channel Type	ATDMA	ATDMA	ATDMA	ATDMA	ATDMA

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
Unerrored Codewords	374523439	1644568466	1644574649	1644580660	1644588215	1644595217	1644600486	1644604749	1644618418	1644624136	1644634516	1644642405	1644649278	1644655384	1644665902	1644676100	1644697523	1644706397	1644718534	1644721043	1644731820	1644738709	1644750822	1644759386	1644770055	1644782761	1644793221	1644799400	1644805264	1644808021	1644816008	374523439
Correctable Codewords	336423118	2314	2406	2208	2456	2107	2252	2657	1692	1698	1482	1473	1507	1483	1625	2114	1734	1130	902	1462	981	947	818	958	976	1027	966	1054	848	1033	932	336423118
Uncorrectable Codewords	2238	1360	1449	1441	1377	1426	2137	2412	1729	1746	1824	1874	1738	1946	2318	3295	2570	1286	1233	1232	1069	1220	1315	1363	1485	1540	1590	1510	1650	1539	1601	2238

When it's up I get stats like this:

XFINITY Network

Internet:Active

Local time:2021-07-11 17:44:38

System Uptime:0 days 10h: 14m: 26s

WAN IP Address (IPv4):

WAN Default Gateway Address (IPv4):73.222.152.1

WAN IP Address (IPv6):

WAN Default Gateway Address (IPv6):

Delegated prefix (IPv6):

Primary DNS Server (IPv4):75.75.75.75

Secondary DNS Server (IPv4):75.75.76.76

Primary DNS Server (IPv6):2001:558:feed::1

Secondary DNS Server (IPv6):2001:558:feed::2

WAN Link Local Address (IPv6):

DHCP Client (IPv4):Enabled

DHCP Client (IPv6):Enabled

DHCP Lease Expire Time (IPv4):2d:19h:24m

DHCP Lease Expire Time (IPv6):0d:0h:0m

WAN MAC:

eMTA MAC:[Edited: "Personal Information"]

CM MAC:[Edited: "Personal Information"]

Initialization Procedure

Initialize Hardware:Complete

Acquire Downstream Channel:Complete

Upstream Ranging:Complete

DHCP bound:Complete

Set Time-of-Day:Complete

Configuration File Download:Complete

Registration:Complete

Cable Modem

HW Version:2.0

Vendor:Technicolor

BOOT Version:S1TC-3.63.20.104

Core Version:1.0

Model:CGM4331COM

Product Type:XB7

Flash Part:8192 MB

Download Version:Prod_20.2_d31 & Prod_20.2

Serial Number:304930041131106155

Downstream	Channel Bonding Value
Index	20	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	21	22	23	24	25	26	27	28	29	30	31	32	33	34	48
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked
Frequency	513 MHz	405 MHz	411 MHz	417 MHz	423 MHz	429 MHz	435 MHz	441 MHz	453 MHz	459 MHz	465 MHz	471 MHz	477 MHz	483 MHz	489 MHz	495 MHz	507 MHz	519 MHz	525 MHz	531 MHz	543 MHz	549 MHz	555 MHz	561 MHz	567 MHz	573 MHz	579 MHz	585 MHz	591 MHz	597 MHz	603 MHz	688000000
SNR	43.2 dB	43.0 dB	43.2 dB	43.0 dB	43.0 dB	43.0 dB	43.0 dB	43.0 dB	43.0 dB	43.0 dB	43.1 dB	42.9 dB	43.0 dB	42.9 dB	42.9 dB	42.9 dB	42.9 dB	42.9 dB	42.7 dB	42.7 dB	42.7 dB	42.8 dB	42.7 dB	42.4 dB	42.4 dB	42.3 dB	42.5 dB	42.4 dB	42.4 dB	42.5 dB	42.2 dB	NA
Power Level	0.1 dBmV	0.7 dBmV	0.6 dBmV	0.6 dBmV	0.7 dBmV	0.7 dBmV	0.6 dBmV	0.6 dBmV	0.4 dBmV	0.3 dBmV	0.2 dBmV	0.1 dBmV	0.1 dBmV	0.2 dBmV	0.4 dBmV	0.5 dBmV	0.2 dBmV	0.4 dBmV	0.9 dBmV	-1.1 dBmV	0.6 dBmV	0.5 dBmV	0.8 dBmV	-1.4 dBmV	-1.4 dBmV	-1.4 dBmV	0.8 dBmV	0.5 dBmV	0.5 dBmV	0.8 dBmV	-1.4 dBmV	NA
Modulation	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	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

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	41 MHz
Symbol Rate	5120	5120	5120	5120	1280
Power Level	45.8 dBmV	46.8 dBmV	47.3 dBmV	47.8 dBmV	46.5 dBmV
Modulation	QAM	QAM	QAM	QAM	QAM
Channel Type	ATDMA	ATDMA	ATDMA	ATDMA	ATDMA

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
Unerrored Codewords	382252220	1665608171	1665619875	1665631672	1665645390	1665657712	1665668832	1665678617	1665698396	1665709868	1665725890	1665740097	1665753338	1665765177	1665781687	1665798153	1665825183	1665840581	1665856187	1665864678	1665881506	1665893953	1665911809	1665926085	1665942491	1665961227	1665978377	1665990914	1666002238	1666010144	1666021318	382252220
Correctable Codewords	342585645	3448	3576	3365	3546	3313	3380	3815	2715	2705	2463	2411	2365	2420	2446	3039	2451	1780	1565	2229	1621	1760	1506	1592	1696	1750	1677	1696	1483	1615	1512	342585645
Uncorrectable Codewords	3238	2228	2323	2221	2189	2156	2887	3222	2491	2570	2686	2771	2517	2723	3048	3980	3147	1807	1727	1774	1563	1706	1874	1960	2105	2219	2345	2240	2506	2317	2306	3238

Responses

EG

Expert

•

111.3K Messages

4 years ago

Yep. The upstream power is too high in the first C&P and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

I realize none of this may apply, but I'm going to include it anyway;

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.

Good luck !

0

Your Home Network

user_67421c

Internet goes out several times a day. Upstream channels not locked when it happens.

XFINITY Network

Initialization Procedure

Cable Modem

XFINITY Network

Initialization Procedure

Cable Modem

EG

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