Intermittent Connectivity with T3, T4 Timeouts and no block sync​​ conditions

Please redact all of the CM MAC and the CMTS MAC addresses in your error log entries for your privacy. They are considered to be personal information. The posting of personally identifiable information is a violation of their forum guidelines. The forum bot will not allow your post to be seen publically. It flagged your post as "Private".

OK so even though the signal status values looked OK at that snapshot in time, the error log entries confirm 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 values 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 (The Digital Care Team) who are available to these boards. They will be able to poll the CMTS (Cable Modem Termination System) to check for any real-time degradation and / or error reports, see your node / cable plant, and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll the CMTS for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

@EG Thank you very much!

Just for good measure, here is the most recent status on my channels and event log:

Ok, I have a technician coming this Thursday.  Xfinity Support sent a configuration signal to my modem and found packet loss and areas of signal that are null when they should be polling.

Please post back here about how things turn out after the tech visit.

Current channel status for today.  A single T3 timeout is only listed in the event log right now (I power cycled the modem yesterday) but the number of uncorrectables is more than corrected so the issue remains despite the robot phone call I got from Comcast today saying that my issue is fixed and that I probably don't need a tech to come out which is the opposite of what I want.

I've also discovered that, according to an FAQ about signal levels for my modem on Arris' website, the acceptable upstream power levels when using ATDMA and a symbol rate of 5120 Ksym/sec are 45 dBmV to 51 dBmV.  I've never seen my power levels be 45 or more but the closest I've seen it be is 44.8, which was 8 days ago.  Right now, everything is sitting at 43.  I don't know if this a great cause for concern but the FAQ does suggest that I have my provider adjust the signal level to the acceptable range.

The link for the FAQ site for my modem is this.

*EDIT

According to new information I found, I should disregard what Arris says as the equipment Comcast uses makes sure my power is at optimal levels.

@EG Two techs came out today, one who was a supervisor who left me their card.  They replaced the coaxial cable running from the modem to the box and said that the cable running to the pole is good.  They found that the upstream power coming from my modem was 3 dB more than what was being read with the meter or at the box, I don't remember exactly, but they made it so the upstream power coming out matched my modem's.  They were not exactly sure if it was really my modem causing this power issue.  They also replaced the coaxial cable running from my modem to the box so no more additional splices on my line.

They also said that there was a team at the CMTS doing some testing and they would test the node in my area for any issues.

So far, everything has been fine.

@user_7c0e97 

Here's how to send them a DM......;

To send a direct message (private message);

Click "Sign In" if necessary.
 
Click the "Direct Message" icon  in the upper right corner or https://forums.xfinity.com/direct-messaging 
 
Click the "New message" (pencil and paper) icon.
 
The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there.
 
As you are typing a drop-down list appears. Select "Xfinity Support" from that list.
 
An "Xfinity Support" graphic replaces the "To:" line.
 
Type your message in the text area near the bottom of the window.
 
Press Enter to send it.

[Permission from and credit given to BruceW].

Around 7:20pm yesterday, talking to XfinityEthan about the promotional offer for my plan, my internet went off and my modem reset.  If this was due to maintenance work at the CMTS or the node in my area or the same issue that has been plaguing me, I don't know.

Here is my current channels status and event log:

Hello,

I too have been dealing with numerous T3 timeouts/intermittent connectivity issues here in the Indianapolis area for the past several months. I've reached out to Xfinity countless times, and have yet to receive a resolution. I was told my hardware was to blame, even though the issue started with my Netgear Nighthawk AC1900, but continued when I upgraded to a combination of the Arris Surfboard SB8200 and TP-Link Deco AX3000, and then continued further when I replaced my modem with the Arris Surfboard S33 at the recommendation of Xfinity (as I later upgraded to the 1Gbps download plan).

A technician has come out twice and has confirmed everything looks good in my home, as well as outside of my home, regarding coax. 

The last visit the technician told me monitoring would be set up to check the node near my home. I never heard back about this. 

I am reaching out to Xfinity via this forum in hopes of finally getting a resolution. I have been customer for roughly 6 years and will be switching to T-Mobile if this is not resolved when the tech visits for the 3rd time tomorrow. 

@XfinityEthan is there an update on the node issue?

So far I'm still getting uncorrectables and T3 Timeouts but thankfully the issue seems to be nowhere near how it was before.  As for the uncorrectables and T3s, I do not know if this is normal for almost 2 days of uptime for my modem (I power cycled it on the 13th) @EG .

My channels and event log for today:

Well what timing, my internet just went off at 3:02pm and is still off.  I'm on my phone.

Seems I spoke too soon.  Just had a T4 timeout and the modem reset.  I see I also had a T2 timeout.

Dang, it just went off again.