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Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

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Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

I have been having intermittent connectivity issues since around July 26th. My modem is an Arris SB6183 that is brand new (less than a month old).  I have attempted the following troubleshooting steps without success: tightening the connections in my apartment (I live in an MDU), replacing the router with a known good, replacing the modem with a known good, connecting the modem to the walljack with a shorter coax cable. Internet access is the only service I have with Comcast; The modem is the only device connected in my apartment. There are no splitters in use. I happened to notice that the error log on my modem was full of errors, including the following (I do not have the records from my modem from this point in time unfortunately): Started Unicast Maintenance Ranging - No Response received - T3 time-out, Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out, Dynamic Range Window Violation, Timing synchronization failures. Aside from an excessive number of corrected/uncorrected errors, I can verify that all of my DS/US statistics were within acceptable ranges at that time (DS signal was between -4/+4, SNR was between 38-42, US signal was usually between 28-30, but would randomly increase up to 50 or so before dropping back down to 28-30. After hours of troubleshooting/browsing relevant topics online, I deduced that the most likely culprit was noise affecting my US signal. I contacted Comcast on 8/8 and they scheduled a tech visit on 8/26. Upon inspecting the signal from the tap, he noticed that my upstream SNR was at 26 (I was told this should be 35 min) and that a maintenance team would need to be dispatched to resolve the issue. While the tech was opening the ticket, a tenant from another building approached him and just so happened to inform him that he has also been receiving T3 errors. The maintenance team arrived this morning (8/27) and I later received an automated call informing me that the repairs were complete. Sadly, the issues continue to persist. I called Comcast this afternoon (8/27) and the agent said that it looked like "the node had slowed to a crawl" and that he would file an unreported (or unregistered? i can't remember that exact terminology used) outage and that another mainteance team would need to be dispatched. Unfortunately, the call was disconnected before we could finish. I called back a second time and spoke with another agent. She told me that there was still ongoing maintenance in my area and that could be the cause.  I was also informed that the first agent I spoke to scheduled another tech visit on 9/23. (A month?! Are you kidding me?!). She did place me on a waiting list for an earlier appointment for 9/9. I am incredibly frustrated right now. I can undertand a week, maybe two at the most, but a MONTH? These wait times are absolutely ridiculous. I understand that these things can take time, but when you inform a customer that an issue has been resolved only for it to continue (or even get worse, in some cases) you really damage customer faith and your own credibility. Sorry for ranting, I appreciate anyone who can help. Oh, and here are the stats from my modem as of now:

Screenshot_2019-08-27 Status.pngScreenshot_2019-08-27 Event Log.png

Expert

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Can't see your pics. Since you are a new poster, they need to be approved by a Forum Admin. That could take some time. In the interim, you could try hosting them at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to them here.



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Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Here are the links to the modem logs on Photobucket:

 

Status

 

Error Log

Expert

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

The signal stats are o/k but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) 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 !

 

 



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Official Employee

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

HDesign, appreciate you posting about your connectivity concerns here on the forums! I'd be happy to take a closer look into this and get to the bottom of this with you. 

 

Please send me a private message with your full name for help. Just click my name (ComcastKenF) and then on the next page, you'll see an option to send a private message on the right. 


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Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

The technician that came out on 8/26 checked the signal at the tap on my building and confirmed that the upstream SNR was too low (I'm unsure about the stats on my Upstream Rx Power and Upstream ICFR). It was at 26, and he said it should be a minimum of 35. Additionally, it seems that some of the other people who live in my apartment complex are experiencing issues as well, so it isn't just my service that is being affected. I had also considered that the CMTS may be experiencing issues (overloaded, perhaps?). It could be a bad amp/trap on one of the lines, a line could be damaged or have water in it, or it may be due to excessive noise on the plant floor. In any case, your assistance is greatly appreciated.

Expert

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

O/k so FWIW, an overloaded node would not make your upstream signal strength shoot up into the 50 dB range like that as you stated in your first post. There is something intermittent going on somewhere with the connection to the Comcast system.

 

Have you sent @ComcastKenF the private message that he requested ?



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Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Okay, thanks for the info. I did send a PM to ComcastKenF with my account details. Hopefully I'll hear something soon.

Official Employee

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

HDesign,

 

Got your message, thanks! Looks like there are power issues and some noise at the node so we'll need to get that addressed. First we'll look for a sooner appointment. 

 

 


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Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Hello everyone,

Just thought I'd give an update. The issues at my node appear to have been resolved. While I am seeing some issues, they have greatly decreased in severity and frequency. The interior wiring from the wall jack in my apartment (I live in an MDU) to the outside of the building near the tap is an old RG-59. The ttechnician that noticed this told me that this outdated cable was a prime suspect for the source of my ongoing issues. i am currently in the process of getting a new line run from the tap on the side of my building to the inside of my unit. 

Official Employee Digital Care

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Hello, thank you for your update/reply!How have your services been and has your old line been replaced?

 

 


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Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

My internet service has definitely improved since the node was adjusted. I am still getting a fair amount of packet errors and occasional disconnects (though much less than before). I have not yet had a new line run; I currently have an appointment on 9/11 for another technician to come and review my signal stats and put in another order to have a new line run.

Official Employee Digital Care

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

That's good news! Once we get the line replaced, this should resolve the rest of the issues you are currently seeing. Please keep us updated. We really appreciate your patience while we work to get this taken care of for you. 


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Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Okay, the technician just left. He said my signals still look good and scheduled another MDU rewire for tomorrow (9/12) between 2-5pm. Hopefully they'll be able to run a new line without any issues.

Frequent Visitor

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

The technician scheduled to perform the rewire said it would be best to run the line underground since regulations are becoming more strict about doing so around the outside of the building (he said he'd been to some MDU's where the residents had the lines on the side of the building simply cut off altogether). He said he would schedule someone to come out and survey for any potential water/gas/electrical lines nearby before the line was buried (I was told this could three weeks or more. Ugh.). I was then told another Comcast technician would have to come out to connect the line and balance it once it was run. He did check the signal levels coming from the wall jack and said they were a little high. He installed a 4-way splitter to add attenuation and bring the signal down. Modem has been up for an hour and I haven't seen an packet errors.....yet:Screenshot_2019-09-12 Status.png

I tried posting to imgur/photobucket, but I was having problems. Sorry if you can't see the image.

Official Employee Digital Care

Re: Connectivity issues; Started Unicast Maintenance Ranging - No Response received - T3 time-out

Awesome, thank you for the update and glad to hear our local team has been working with you on this issue.  Please continue to keep us updated and thank you for your time!


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