Visitor
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4 Messages
Intermittent Service Drops Related to T3/T4 Time-outs
On a daily basis, I have been experiencing multiple drops in service ranging in severity from a few minutes (until modem reset) to greater than an hour. I utilize my own modem and router for my service. The modems in-use are identified in my discussion below. I have brought this issue to Comcast's attention via a tech visit on May 19th; however, the issue has persisted following the visit.
I have taken many steps to troubleshoot the issue on my end (including all those listed by Comcast in their Troubleshooting Tips) with none providing a permanent resolution. A general synopsis of the troubleshooting steps taken include:
- Removed all unnecessary splitters within my home. All equipment (modem, main cable box, and one satellite box) now have a dedicated line from the one and only splitter located at the drop line connection to the house. The Comcast tech also replaced this splitter during his visit to be safe.
- All coax cable runs and F-connectors within my home have been replaced and verified to be in good condition by the Comcast tech.
- Three different modems have been activated and used over the last few months (Arris S33, Motorola MB8611, and Arris SB6190). This was done to verify (1) there was not a fault with the modem and (2) there was not a discrepancy in service between the DOCSIS 3.1 and DOCSIS 3.0 standard at my location. Each modem was factory reset after the issues persisted. The factory resets did not improve the drop outs.
- The Comcast tech verified the signal to my home at the drop location was above average (as my drop is run to my house off an amp located off the pole across the street). He did not, however, acknowledge that my issue was identified as being intermittent and thus potentially unidentifiable during the time of his visit.
Over the time the issues have been occurring, I have also captured various snapshots of my modem performance via channel status and event logs to provide a clearer picture of my issue. As mentioned, the information was captured for three different modem models. This information relative to representative drop out occurrences is provided (with MAC addressed removed) in the links below:
- Arris S33 Channel Status & Event Log
- Motorola MB8611 Channel Status & Event Log
- Arris SB6190 Channel Status & Event Log
From my interpretation of the modem information, the downstream SNR and power levels are well within spec. The upstream power levels are also within spec. However, the number of uncorrectables that are correlated to the T3 and T4 time-outs are unacceptable. The event logs seem to indicate that there is an intermittent issue with upstream communication.
Taking into account this information and all the troubleshooting steps I have taken, I believe there to be either (1) a potential issue with the drop line providing service to my house or (2) an issue on Comcast's end related to the firmware/configuration provided to each modem. I am no expert, though, and I am open to exploring options that achieve an expedient solution to my issue. If someone could please provide me with a clear path forward taking into account this information, it would be greatly appreciated. Thanks.
Accepted Solution
PostByCoast
Visitor
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4 Messages
2 years ago
For the sake of public transparency, an update regarding my issue:
Xfinity Support followed up with my post and checked my signal attributes on their end. There were no issues that were relevant to solving my service drops identified. As such, a second tech was sent out on 6/13 to further investigate the issue. Upon arrival, the tech and I had a conversation about everything that I was seeing, the steps I had taken to troubleshoot to that point, and the items that were investigated on my first tech visit. He then proceeded to verify that everything was still in good condition within my home before climbing the pole across the street to investigate the signal across my drop line as well as replace the F-connector at that location. When he returned, he showed me that the condition of the F-connector was fairly corroded and the likely source of my intermittent issues. However, in order to be thorough in addressing things, he also put in a maintenance ticket to further evaluate the line/amp from which my drop was fed to ensure there were no other issues he was not equipped to check himself.
As a result of the steps taken on this tech's visit, I have had uninterrupted service for greater than 5 days now using my Arris SB6190 modem. I have not tested my Arris S33 or Motorola MB8611 modems to verify a full resolution in that regard, but considering a corroded F-connector opposite my drop line seems to be the culprit, I'd like to be optimistic. Also, although the process to get to this point wasn't the most fun I've ever had, I at least want to give a big thanks to the tech, Chris, that came out. He was extremely professional, thorough, and understanding with respect to tackling the issue for me.
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mistergsf
Contributor
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66 Messages
2 years ago
I recently activated my own modem, Arris S33, and having a similar connectivity issue. Since activating, my internet connection drops every day at around 1AM and connection returns within 5 minutes. Never longer than that. I installed on May 27 and only started noticing a few days later. I'm a night owl so I'm still up returning emails and surfing the web. Connection drops every time at 1AM - 1:03AM.
Haven't really done any troubleshooting at all since my dropouts haven't manifested to anything greater. It's interesting to read your detailed post. I may have to due some further digging around on my issue.
I'm assuming the dropouts you are experiencing happen when on wi-fi and when wired to ethernet? My wi-fi router is an Amplifi Alien mesh and I'm a couple of firmware updates behind. I'm on 3.7.1 and current firmware is 4.0.1.
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EG
Expert
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114K Messages
2 years ago
@PostByCoast
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 !
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