Numerous Uncorrectables

It's really not that many, but it depends on the total uptime of the modem since it was last re-booted. The signal stats are good.

Are you actually experiencing any connectivity issues, or are you just focusing on those bit errors ?

EG,

Aren't any uncorrectables a problem?  I have been researching and it seems they are.  In answer to you question, I have latency issues which is why I started looking at the modem logs.

Uptimewise, I hard reset this modem a couple of days ago in a effort to eliminate the latency issues so these uncorrectables are all recent.  

https://arris.secure.force.com/consumers/articles/General_FAQs/SB8200-Cable-Signal-Levels/?l=en_US&fs=RelatedArticle

https://www.dslreports.com/forum/r30372719-Signals-What-a-difference-a-new-drop-line-can-make

Arris just told me that the upstream power is too low and that there should be 8 channels instead of 5.  Upstream power should be It should be minumum 45 dBmv and max 61 but is is 37.

https://arris.secure.force.com/consumers/articles/General_FAQs/SB8200-Cable-Signal-Levels/?l=en_US&fs=RelatedArticle

Any additional help or insight would be appreciated.

@user_cd429e 

You wrote: "Aren't any uncorrectables a problem?"

Not if they are a small amount over an appreciable period of time.

Just to clear things up about Arris's assertions;

Arris is wrong ! They have been passing the buck and have been conning people with that statement lately !!  They are probably trying to cover up for their liabilities about the lawsuits against them because of their use of the horrible Puma 6 chipsets... Only the Comcast plant / engineering specs matter;

Specification Min Max
Downstream Power Level 
Cable Modems -10dBmV +10dBmV
Gateways and EMTAs -7dBmV +7dBmV
Downstream Signal to Noise Ratio 35dB -
Upstream Power Level +35dBmV +50dBmV
Upstream Signal to Noise Ratio 31dB -
Upstream Receive Power -2dBmV 
+2dBmV

They are also wrong about the number of upstream channels as Comcast currently offers only up to five channels no matter what the modem is capable of.

Moving on. You stated that you are having a problem with "intermittent latency". That could be being caused by an RF signal impairment / line impairment of some type, or by an intermittent capacity / traffic congestion problem on your local cable segment / local node. If it is the latter, there is not much that you can do about it other than to complain to them persistently about it.

That said. I'll ask for more info which can help to reveal signal problems. Are there any RF error log enties being shown in the 8200 cable modem ? If so, please post them in their entirety.

Is there a router / WiFi connection in the mix here ?

Hello EG,

This is an SB8200 which does not appear to use the PUMA chipset.  https://www.mbreviews.com/arris-sb8200-review/

I do have a WRT1900AC Linksys router with 4 hardwired connections and wifi. The hardwired connections distribute to SB3005 switches and then to devices on the hard wired network.  WiFi is used for mobile devices.  

All testing is done on a PC that is on the LAN - RJ45 connection.  I have monitored the Internet bandwidth usage via my router login and see nothing pulling high BW.  For instance my main PC, where I do this testing, typically is using between .02Mbps and .08Mbps total BW.  

When seeing latency issues I use Ping Plotter program to monitor the latency.  

Here is the log from this morning.  I see no entry updates since the service call yesterday when the line technicians disconnected my line for testing.

What I have in mind from here is:

Xfinity has escalated and a higher level technician will be calling me next week.  

I will once again hard reset my modem, mainly to clear the logs and current results.  

I will connect a laptop directly to modem's RJ45 (not through my router network) and check the modem logs.  

I have ordered a high quality splitter and 75 ohm termination cap and may install these to see if my upstream power levels increase,

@user_cd429e 

It doesn't seem that you understand. It doesn't matter whether or not your particular modem uses it (the Puma 6). They are saying that as a a boilerplate response to help them to get away with murder (so to speak) legally. It's being used as a universal excuse so that they don't have to address their problem. They are passing the blame for their deficiencies on to the ISP's instead. You don't need to raise the upstream power. There is nothing wrong with it. The Comcast system automatically controls it to a level that it needs to clearly hear the modem at their headend. I hope that that was clearer for you. 

That said.

The signal stats are o/k (as stated), but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) /  an upstream channel-return path impairment somewhere.

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !

EG, I just factory reset my modem to get a better picture of things as they stand now.  Interestingly I now have no uncorrectables.  I will check it again later and each day.  Any thoughts on this change and on how current the modem logs are when they are viewed?  All that Xfinity did was verify the nodes near me and test my line which they said was good.  Otherwise they removed the splitter which had a very loose terminator on the unused output.

The bit error counter and the error log entries get reset to zero every time the device gets reset or re-booted. That stuff is cumulative and starts re-counting and re-recording from that point on until the next reset.

Ok so a modem restart would clear the buffers?

Yup

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Update, I installed a splitter today (Extreme 2 Way HD Digital 1Ghz High Performance Coax Cable Splitter BDS102H).  I hard reset the modem and then checked the logs.  The results are that the Upstream Bonded Channels Power increased from 37 dBmv to 40 dBmv and that the Downstream Bonded Channel power changed from an average of 4.6 dBmv to and average of 1.7 dBmv.  See below... 

Before adding splitter:

Having trouble posting

Update, I installed a splitter today (Extreme 2 Way HD Digital 1Ghz High Performance Coax Cable Splitter BDS102H).  I hard reset the modem and then checked the logs.  The results are that the Upstream Bonded Channels Power increased from 37 dBmv to 40 dBmv and that the Downstream Bonded Channel power changed from an average of 4.6 dBmv to and average of 1.7 dBmv.  See below... 

Before adding splitter:

For what ? You don't need that splitter. The stats were already in spec. It wasn't broke. You didn't need to fix it. Besides, a splitter should not be used as an attenuator. It could make things worse. "Attenuator Pads" are made specifically for that purpose.