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Nightly T3 Timeouts

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Frequent Visitor

Nightly T3 Timeouts

Every night this week my internet and TV service has been going offline. The internet is more sensitive to whatever signal issue is going on, so it has issues all night from 9PM to 7AM and the TV only seems to go out in the middle of the night 12AM-4AM when the signal issues get really bad. I’ve already had a tech onsite who replaced all the lines and equipment in my house. The line from my house to the telephone pole is also new. Support was saying it was my modem, so I replaced that too and it still goes out at night. Both modems reported constant T3 timeouts and my firewall logs between 15-30% packet loss and even going completely offline.

My service is fine during the day, but the problem is I work most of the day and get home at 8PM. I’m also supposed to be on call for work afterhours as well, but with my internet dying at night I can’t do my job without having to drive an hour to get to work. I had this same issue last year and it started in December as well and lasted for 2 months without any real fix even after 6 techs were sent out. I’m afraid the same thing is happening again as Comcast didn’t really fix the issue last time and just kept sending out techs in the day to check for issues. Of course, since the issue only happens at night the techs never find anything and none of them are willing to stay late for it to actually start breaking. I’m not sure if it’s the colder weather at night during this time of year that’s causing something to break upstream, but this issue coming back at around the same time it happened last year really has me nervous. I really don’t want to go without service for 2 months again.

I’m willing to provide any logs or information needed to get this resolved. I need to be able to work from home and Comcast is my only ISP option in my area.

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Frequent Visitor

Re: Nightly T3 Timeouts

Here are my modem logs. I only have 2 days of logs because this modem is new and only 2 days old. My old modem had the same T3 time out logs as well: https://pastebin.com/zGi9ZVXC

Here are my firewall logs: https://pastebin.com/kieDn6kW

Here are signal levels when it starts to act up. Had to wait for it to break again: https://imgur.com/a/OUfSFJ0

Here are signal levels from during the day when the service is stable: https://imgur.com/a/HMEz07X

 

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Expert

Re: Nightly T3 Timeouts

Question. Have you been resetting the modem via the online tool ? I ask because I'm seeing a bunch of these messages in the error log entries;

 

" Resetting the cable modem due to docsDevResetNow".

 

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. 

 

I say that because your TV service has an issue as well. Good luck !



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Re: Nightly T3 Timeouts

Thank you for the reply.

 

Those resets are probably from Comcast technical support. I've tried calling them whenever this happens, and they reset it every time. At this point I'm just calling them so I can get credit for the outages, but they still insist on rebooting the modem every time.

 

There are no splitters besides the main one that comes into the house and the modem. I've even traced the line in the attic and replaced it with a new line just in case.

 

I've also updated the post with the signal levels to have signal levels from the day when things are stable. I'm not familiar with reading signal levels so I'm not sure if there's any useful information in there, but I posted it just in case.

 

What has me stumped is that this only happens at night. I check my logs for the modem and the firewall and there are no T3 timeouts or packet loss warnings at all during the day.

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Expert

Re: Nightly T3 Timeouts

O/k if none of the tips that I provided apply, you need to insist on a tech visit. 

 

I'll repeat this again;

 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. 

 

Good luck with it !! Please post back with how things turn out.

 



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Re: Nightly T3 Timeouts

Just had a tech out here. The onsite tech didn't see any issues, as expected for the daytime. They still contacted their maintenance department after some convincing. After maintenance looked into the issue, they found out the node in the area was having issues between 9PM and 7AM for the last 5 or so days. Maintenance will look at the node later today or on Monday. Hopefully this resolves the issue.

A bit disappointed with the communication at Comcast support though. The on-site tech had no idea about the nightly outages and was under the impression it was just a modem install. And of course, phone support's idea of asking the tech to stay late or come back at night was a no go. I don’t blame him though.

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Re: Nightly T3 Timeouts

Hopefully this leads to a solution ! Thanks for posting back !



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Re: Nightly T3 Timeouts

Just spoke with a line tech that was out here. The issue was caused by temperature changes at night causing a piece of equipment upstream to spike power output. They are working on fixing it now. Also confirmed that it was the same piece of equipment that was out here last year when it was out for 2 months. We did have a hurricane pass through last year that may have damaged it to make it malfunction when temperature changes. Shame it took Comcast a year to acknowledge the issue, but at least it's getting addressed now.
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Re: Nightly T3 Timeouts

I wish the local maintenance team in my area was as diligent.