_Jim_'s profile

Contributor

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15 Messages

Sun, May 9, 2021 7:56 PM

Recent quality issues; contemplating switching out ARRIS SB6190 to a SB8200

Hello!

 

We’ve been using Comcast Internet at the same house since 2005, with very few problems over the years. We’ve always used our own cable modems and routers. There is a dedicated coax line entering the house into our “home office” where the modem/router live – we’ve only ever used that one outlet to connect the modem. Our current modem is an ARRIS SB6190, which has been in place since January of 2017. I do remember some Comcast folks coming out to run a new cable from the street box to our house, but that’s been at least ten years ago. I don’t remember if that was done to address a specific problem, but I don’t think so.

 

Over the last several months, we’ve experienced intermittent quality problems with the Internet – dropped connections, slow speeds, and significant packet loss when using game streaming services over UDP protocols. Sometimes these issues are chronic and occur for days at a time, and other times they are short-lived (hours). I have a permanent work-from-home IT job, and use computers with Ethernet connections in the home office (it’s only myself and my wife at this point). Whenever there are problems, I’ll open a browser to the Xfinity speed test site and run the test. Our current plan is a 200 Mbps down / 5 Mbps up, and when things are working normally, the Xfinity speed test shows ~ 230 Mbps down and 6 Mbps up, quite consistently. When there are problems, the download speeds will be much slower, usually under 100 Mbps. We’re having problems today, and the download speed just showed 39.3 Mbps. Earlier in the day it was 75 Mbps. The upload speed doesn’t seem to degrade/change much, and that is at 5.8 Mbps currently. I’ve been spending more time at a shared office space recently, where there is symmetrical 1 Gbps Comcast Business service, to avoid problems at the house. I’m getting spoiled by that stability at the shared space.

 

During the problematic times at the house, I’ll check the modem’s status and event log, and then restart it (via the link in the Comcast web site’s device page) as well as the router. When the cable modem is back up and there are still problems, there will be one or more downstream channels in a “Not Locked” condition, and several of the others which are “Locked” but have large numbers of “Corrected” and “Uncorrectables.” When things are normal, all of the downstream channels will be “Locked,” and have few “Corrected” and nearly zero “Uncorrectables.” I have screenshots of both of these statuses. In terms of the modem’s event log, when there are problems, there will be frequent/recent “RCS Partial Service” and “Started Unicast Maintenance Ranging - No Response received - T3 time-out” messages.

 

I’m also aware of the “Intel Puma 6 chipset” controversy, and have researched that a bit. The information I’ve read about it was a bit cringeworthy, not written by network professionals and/or not speaking English as a first language. Despite this and my inherent skepticism, I still believe there is a strong case since problems often go away after a restart of the modem. In recent days, though, those restarts are not bringing resolution.

 

I’m seeking advice on what to do next – I’ve long wanted to replace the modem with an SB8200 to get DOCSIS 3.1 and eliminate the Puma 6 chipset problem, and will be pulling the trigger on that shortly. However, I don’t expect that will bring lasting resolution, and need to know what to do when it doesn’t. Perhaps another physical inspection of the line would be in order.

 

Thanks for any help!

 

Jim

Responses

_Jim_

Contributor

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15 Messages

3 m ago

Here are the screenshots of the statuses "good" at the top, "bad" at the bottom:

https://imgur.com/a/DjSCjIK

(edited)

_Jim_

Contributor

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15 Messages

3 m ago

Here is the current speedtest:
_Jim_

Contributor

 • 

15 Messages

3 m ago

And status:

Status

The statuses listed show the connection state of the cable modem. They are used by your service provider to evaluate the operation of the cable modem.
Startup Procedure
Procedure 	Status 	Comment
Acquire Downstream Channel 		Locked
Connectivity State 	OK 	Operational
Boot State 	OK 	Operational
Configuration File 	OK 	
Security 	Enabled 	BPI+
DOCSIS Network Access Enabled 	Allowed 	

Downstream Bonded Channels
Channel 	Lock Status 	Modulation 	Channel ID 	Frequency 	Power 	SNR 	Corrected 	Uncorrectables
1	Locked 	256QAM	16	495.00 MHz	8.30 dBmV	33.60 dB	9112	0
2	Locked 	256QAM	17	501.00 MHz	8.20 dBmV	31.99 dB	52295	403
3	Locked 	256QAM	18	507.00 MHz	8.50 dBmV	33.38 dB	882	0
4	Locked 	256QAM	19	513.00 MHz	8.60 dBmV	34.93 dB	795	0
5	Locked 	256QAM	20	519.00 MHz	8.60 dBmV	37.36 dB	733	0
6	Locked 	256QAM	21	525.00 MHz	8.80 dBmV	31.34 dB	1041798	115
7	Locked 	256QAM	22	531.00 MHz	8.30 dBmV	27.52 dB	123216714	32072503
8	Locked 	256QAM	23	543.00 MHz	8.10 dBmV	37.36 dB	707	0
9	Locked 	256QAM	24	555.00 MHz	7.60 dBmV	26.87 dB	165135732	102583605
10	Locked 	256QAM	25	561.00 MHz	7.60 dBmV	28.46 dB	139874113	18618760
11	Locked 	256QAM	26	567.00 MHz	7.90 dBmV	30.37 dB	388501	10516
12	Locked 	256QAM	27	573.00 MHz	8.20 dBmV	33.49 dB	798	0
13	Locked 	256QAM	28	579.00 MHz	8.50 dBmV	36.39 dB	650	0
14	Locked 	256QAM	29	585.00 MHz	9.00 dBmV	36.61 dB	686	0
15	Locked 	256QAM	30	591.00 MHz	9.10 dBmV	33.96 dB	1974	12
16	Locked 	256QAM	31	597.00 MHz	9.10 dBmV	31.92 dB	2392	7553
17	Locked 	256QAM	32	603.00 MHz	8.90 dBmV	35.60 dB	1915	14
18	Locked 	256QAM	33	609.00 MHz	8.70 dBmV	37.94 dB	651	0
19	Locked 	256QAM	34	615.00 MHz	8.20 dBmV	38.61 dB	661	0
20	Locked 	256QAM	35	621.00 MHz	7.50 dBmV	36.61 dB	653	0
21	Locked 	256QAM	36	627.00 MHz	7.20 dBmV	33.60 dB	1639	0
22	Locked 	256QAM	37	633.00 MHz	7.30 dBmV	31.20 dB	178269305	64990656
23	Locked 	256QAM	38	639.00 MHz	7.50 dBmV	37.36 dB	690	0
24	Locked 	256QAM	39	645.00 MHz	7.70 dBmV	37.36 dB	658	0
25	Locked 	256QAM	40	651.00 MHz	8.00 dBmV	38.20 dB	693	0
26	Locked 	256QAM	41	657.00 MHz	8.50 dBmV	38.60 dB	660	0
27	Locked 	256QAM	42	663.00 MHz	8.70 dBmV	38.60 dB	644	0
28	Locked 	256QAM	43	669.00 MHz	8.70 dBmV	38.60 dB	629	0
29	Locked 	256QAM	44	675.00 MHz	8.70 dBmV	38.60 dB	627	0
30	Locked 	256QAM	45	681.00 MHz	8.70 dBmV	38.90 dB	606	0
31	Locked 	256QAM	46	687.00 MHz	8.70 dBmV	38.90 dB	633	0
32	Locked 	256QAM	47	693.00 MHz	8.20 dBmV	38.60 dB	649	0

>>
Upstream Bonded Channels
Channel 	Lock Status 	US Channel Type 	Channel ID 	Symbol Rate 	Frequency 	Power
1	Locked 	ATDMA	4	5120 kSym/s	36.50 MHz	45.75 dBmV
2	Locked 	ATDMA	5	1280 kSym/s	41.20 MHz	45.00 dBmV
3	Locked 	ATDMA	3	5120 kSym/s	30.10 MHz	46.50 dBmV
4	----	----	2	----	23.70 MHz	----
5	----	----	1	----	17.30 MHz	----


Current System Time: Sun May 09 15:04:28 2021

_Jim_

Contributor

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15 Messages

3 m ago

And event log:

Sun May 09 15:05:31 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:05:51 2021	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:05:57 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:06:15 2021	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:06:17 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:06:31 2021	5	Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:06:39 2021	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:06:43 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:03 2021	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:27 2021	5	Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:29 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:41 2021	5	Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:47 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:48 2021	5	Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:07:51 2021	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:08:03 2021	5	Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:08:11 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:08:15 2021	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:08:23 2021	5	RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;Sun May 09 15:08:28 2021	5	Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;

(edited)

_Jim_

Contributor

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15 Messages

3 m ago

Hi Gabe,

Thank you for the follow-up; indeed things are still working fine.

Our wireless needs are pretty light (a couple of phones and laptops)...important things like the TV gear and streaming devices are all using Ethernet. Also, we do the annual commitment thing every year, for a lower rate for sufficient speeds. Like everyone else, we'd like to pay less (Comcast has a monopoly in our area due to a lack of decent alternatives)...we don't feel like the rate is unreasonable, though. For good service, we're willing to pay for it...and the service has been good.

My "hobby" is currently cloud game streaming services (Shadow, Stadia, xCloud, GeForce NOW, etc.), as I believe that's the future of gaming. These services are sensitive to network quality. Obviously, congestion and other issues along the path are a factor, and people generally don't seem to understand that the current technology is far from "perfect." However, when exacerbating issues are introduced "locally" (such as my potentially bad old SB6190 modem)...that's particularly frustrating to me, because those sorts of problems are opaque to normal folks, and they tend to blame the game service providers for problems that are usually outside of the provider's control.

As an example, here is what a "good" session for Shadow looks like (and what I'm experiencing today):

When there were quality problems, it looked like this:

Now, whether the bulk of my quality problems were caused by the SB6190 modem...who knows. But again, so far so good with the SB8200!

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