CM1150V and AX6000 RBR850 internet connectivity issues with Xfinity

Question

So frustrated with my new equipment and internet! Can anyone help? Dumped ATT, got Gig internet with Xfinity, and a CM1150V (for voip) with Orbi AX6000 RBR850 and RBS850 Satellite. Worked great for a week, then started dropping internet connectivity (across devices, including a computer with direct LAN to the RBRR850). I get weird behavior – for example, click to a website, get the frownie face (L website can’t be reached) then immediately loads. Commonly goes down completely overnight, and I have to reboot the modem. That fixes things a short while, then it starts again. Sometimes it works for up to three or four days; other times have to reboot multiple times daily. Had Xfinity techs out twice. First tech said everything should be good, but we took two steps to help: 1) he put a filter on a house downstream that he said was creating noise; and 2) changed it from a 3-way splitter (modem and two TV’s) to a 2-way, with the second splitter downstream for the second TV. Didn’t help. Second tech said lines are great to my modem – maybe try renting an Xfinity modem. (Would have done that out of the gate if I’d wanted to rent.)

When things work great, I can get 800-900 Mb even over wifi adjacent to the RBR850; 450 MB across the house through the satellite (on my phone). My hardwired computer is old, and tops out at about 250 Mb (which is fine – I figure that’s the computer). When it goes glitchy, I get long delays, then fast loading, then later slow speeds, then lose all connectivity.

CM1150V data seems good (SNR, power levels) with the possible exception of uncorrectibles on the OFDM download channel. When it goes completely down, event logs show the modem is not getting any response from Comcast, and it keeps rebooting. But a hard powercycle fixes it for a little while.

Here’s a screen shot of my channel data. (I can post the event logs if that is helpful.)

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

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	531000000 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	20	531000000 Hz	-3.2 dBmV	38.7 dB	0	0
2	Locked	QAM256	17	513000000 Hz	-2.9 dBmV	38.9 dB	0	0
3	Locked	QAM256	18	519000000 Hz	-2.9 dBmV	38.9 dB	0	0
4	Locked	QAM256	19	525000000 Hz	-3.1 dBmV	38.8 dB	0	0
5	Locked	QAM256	21	543000000 Hz	-3.3 dBmV	38.8 dB	0	0
6	Locked	QAM256	22	549000000 Hz	-3.3 dBmV	38.7 dB	0	0
7	Locked	QAM256	23	555000000 Hz	-3.8 dBmV	38.5 dB	0	0
8	Locked	QAM256	24	561000000 Hz	-3.9 dBmV	38.5 dB	0	0
9	Locked	QAM256	25	567000000 Hz	-3.9 dBmV	38.6 dB	0	0
10	Locked	QAM256	26	573000000 Hz	-4.1 dBmV	38.5 dB	0	0
11	Locked	QAM256	27	579000000 Hz	-4.4 dBmV	38.4 dB	0	0
12	Locked	QAM256	28	585000000 Hz	-4.3 dBmV	38.4 dB	0	0
13	Locked	QAM256	29	591000000 Hz	-4.1 dBmV	38.4 dB	0	0
14	Locked	QAM256	30	597000000 Hz	-3.7 dBmV	38.6 dB	0	0
15	Locked	QAM256	31	603000000 Hz	-3.4 dBmV	38.6 dB	0	0
16	Locked	QAM256	32	609000000 Hz	-3.2 dBmV	38.6 dB	0	0
17	Locked	QAM256	33	615000000 Hz	-3.2 dBmV	38.5 dB	0	0
18	Locked	QAM256	34	621000000 Hz	-3.2 dBmV	38.4 dB	0	0
19	Locked	QAM256	35	627000000 Hz	-3.2 dBmV	38.5 dB	0	0
20	Locked	QAM256	36	633000000 Hz	-3.1 dBmV	38.5 dB	0	0
21	Locked	QAM256	37	639000000 Hz	-3.1 dBmV	38.5 dB	0	0
22	Locked	QAM256	38	645000000 Hz	-3.1 dBmV	38.4 dB	0	0
23	Locked	QAM256	39	651000000 Hz	-3.1 dBmV	38.3 dB	0	0
24	Locked	QAM256	40	657000000 Hz	-3.3 dBmV	38.3 dB	0	0
25	Locked	QAM256	41	663000000 Hz	-3.4 dBmV	38.3 dB	0	0
26	Locked	QAM256	42	669000000 Hz	-3.2 dBmV	38.3 dB	0	0
27	Locked	QAM256	43	675000000 Hz	-2.9 dBmV	38.1 dB	0	0
28	Locked	QAM256	44	681000000 Hz	-2.8 dBmV	38.4 dB	0	0
29	Locked	QAM256	45	687000000 Hz	-2.6 dBmV	38.4 dB	0	0
30	Locked	QAM256	46	693000000 Hz	-2.6 dBmV	38.5 dB	0	0
31	Locked	QAM256	47	699000000 Hz	-2.5 dBmV	38.5 dB	0	0
32	Not Locked	Unknown	0	0 Hz	0.0 dBmV	0.0 dB	0	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	1	5120 Ksym/sec	17300000 Hz	46.5 dBmV
2	Locked	ATDMA	2	5120 Ksym/sec	23700000 Hz	46.5 dBmV
3	Locked	ATDMA	3	5120 Ksym/sec	30300000 Hz	46.5 dBmV
4	Locked	ATDMA	4	5120 Ksym/sec	36700000 Hz	46.5 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 ,2 ,3	48	850000000 Hz	-3.4 dBmV	37.5 dB	1108 ~ 2987	60113364	13561874	5017
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

Current System Time:Mon May 04 11:23:46 2020System Up Time:01:49:34

tgary · Answer

Not clear if the screen paste captured the uncorrectables on the OFDM downstream, but in a little under two hours up, it was&nbsp;13561874 correctable, and 5017 uncorrectable.&nbsp;

FURRYe38 · Answer

Have the ISP check the signal and line quality UP to the modem.
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.

tgary · Answer

FURRYe38&nbsp;wrote:Have the ISP check the signal and line quality UP to the modem.&nbsp;Be sure there are no coax cable line splitters in the between the modem and ISP service box.&nbsp;Be sure your using good quality RG6 coax cable up to the modem.Hi, and thank you. They did. The Xfinity tech checked the line from tap to modem, and said it was very strong.&nbsp; (There is a single splitter to pull off the TV line.)&nbsp; I figured my lines would be the first thing Xfinity would blame if they could.

FURRYe38 · Answer

I'd pull the splitter off and directly connect the modem to the line and see if the problem still happens.&nbsp;Also run some speed tests while the modem is connected with out the splitter and with a PC directly connected to the modem with out the RBR online.&nbsp;

tgary · Answer

FURRYe38&nbsp;wrote:I'd pull the splitter off and directly connect the modem to the line and see if the problem still happens.&nbsp;Also run some speed tests while the modem is connected with out the splitter and with a PC directly connected to the modem with out the RBR online.&nbsp;I can try removing the splitter, but doesn't that preclude getting TV service in addition to internet? (Is there something about the channel data that makes you suspect a line issue, even though the tech said the line to the modem was really strong?)&nbsp;&nbsp;&nbsp;I can do a speed test with a laptop or my desktop connected directly to the modem, but neither gets the top speeds I see through the router over wifi, I think because of the age of the PC's components.&nbsp; (They are maybe 5-7 years old.)&nbsp; But I can also do one directly at the RBR using the ORBI app.&nbsp; That's essentially the same thing, right?&nbsp; Doing that, the router is getting the 800-950 Mb levels posted above - until it isn't working, then it gets 0, 2, 6 Mb or whatever.&nbsp;

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CM1150V and AX6000 RBR850 internet connectivity issues with Xfinity

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