Visitor
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13 Messages
Frequent 5-10 Minute Internet Outages: Ongoing Problem
Hello,
I've got a Netgear CM2000, but this problem was also ongoing with my last modem. I'm currently subscribed to the 1200 Mbps plan. I'll encounter multiple outages 5-10 minutes a day where the Internet connection completely drops. During that time, the downstream light on the modem will begin blinking as if it's trying to get a lock. The logs also show a timeout for the OFDM channel. The modem seems to restart itself after 5 minutes and generally comes back online, but it'll occasionally take 2-3 tries which equates to a 10-15 minute outage.
I've had Xfinity techs out twice at this point. The first tech checked a bunch of signals and decided everything was good. The next tech said the line to the house was bad, had it replaced, and then eventually had the whole underground line replaced that goes to the next hop, i.e. 2 houses up the street. He verified this is not an issue with my home wiring or cable modem. I started checking with my neighbors, and all of them are having the exact same issue. Exchanging text messages with the neighbors confirms that when one of us has an Internet drop-out, everyone at the end of the street has one that lasts 5-15 minutes. At this point I'm suspecting that the issue is somewhere further up the street.
The majority of the logs are similar to this:
Sat Jul 31 09:41:06 2021 (Warning (5)) Dynamic Range Window violation
Sat Jul 31 09:41:06 2021 (Warning (5)) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:41:02 2021 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:40:54 2021 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:40:54 2021 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:40:53 2021 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:40:45 2021 (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Sat Jul 31 09:40:36 2021 (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:37:45 2021 (Critical (3)) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:37:45 2021 (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 31 09:37:22 2021 (Critical (3)) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=YY:YY:YY:YY:YY:YY;CM-QOS=1.1;CM-VER=3.1;Modem levels are listed here:
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As mentioned above, this would appear to be more of a systemic issue upstream from our street. Unfortunately I'm not sure who else has opened tickets. We've got a group text going where one person will ask "Is anyone else down?" and sure enough everyone else is down too. FYI I'd just rest the modem, but the "uncorrectables" will frequently increasing during the timeout issue.
What can we do to get this resolved? This issue makes it almost impossible to work remotely.
Adkihn
Visitor
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1 Message
3 years ago
Experiencing the exact same issue as you for months now. Support is 0 help. Technician came out and replaced cables and connections near the modem but issue still occurring. Called support maybe 12 times now.
97219 area?
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TaperCrimp
Visitor
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13 Messages
3 years ago
...and once again it's out with the following error:
This has happened 3 times in the last two days. Every time I try to contact Xfinity support, I'm told "there's a known outage" or "there's a tech in the area". This happens at least once a day, to the point that I'm tethered to my phone instead of Xfinity if I've got anything remotely important. What can be done to get this resolved? The response to this has been beyond disappointing after being a customer for over a decade.
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TaperCrimp
Visitor
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13 Messages
3 years ago
If anyone from Xfinity is reading this, the ticket is <edit ticket #>. I've had the exact same conversation with support a dozen times now. I shouldn't need to look into the cost of a backup line since Xfinity goes down 2-3 times a day for 5-15 minutes at a time. I'm also definitely tired of explaining to support that resetting my modem isn't going to fix a line issue somewhere up the street.
(edited)
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TaperCrimp
Visitor
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13 Messages
3 years ago
On a positive, a line tech was out yesterday that was replacing equipment down the street. On a negative, everyone on the street is still having outages this morning. I've had two since 9 AM Eastern.
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TaperCrimp
Visitor
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13 Messages
3 years ago
The line tech was on our street twice last week. He's tried replacing equipment at two different locations. Everyone on the street is still having 3-4 outages per day, with everyone going down at the same time. @Xfinity Support how do I get them back out here? Every time I report an outage, I get asked to reset my modem, schedule an appointment, offered a Flex, etc. None of that would fix the problem. I literally just want my Internet to quit dropping every few hours. The line tech, i.e. the guy driving the bucket truck, confirmed it's a problem with Xfinity's infrastructure in the area and there's no point in having a tech sent to my house. How do I get them back out to correct this once and for all?
Literally everyone on the street goes down when this happens. It's a problem with one of the underground lines that everyone is connected to. I'm starting to wonder if there's any point in reporting 3-4 outages a day since the response from support is exactly the same, and I spend 20 minutes explaining the exact same problem over and over. At this point I would switch to another provided if I had any viable alternatives. Using my phone as a hot spot is more reliable.
(edited)
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TaperCrimp
Visitor
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13 Messages
3 years ago
Also, just to put it in perspective, each line represents an outage over the last 3 days. Imagine trying to work remotely though this.
(edited)
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TaperCrimp
Visitor
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13 Messages
3 years ago
FYI to anyone reading this:
- I've had 4 tech visits to my house in the last 3 months.
- We've had line techs on our street 3 times, with the most recent being yesterday. They confirmed it's a problem with the street, not my house.
- I took it upon myself to escalate to the local supervisor. His tech thought he'd corrected it, but the problem is still happening.
- I've somehow become the point of contact that asks everyone on the street to continually escalate the issue.
- I've lost 24-36 hours of my life dealing with this that I'll never get back.
This is pure, complete, and total insanity. Nobody should need to deal with this to get an issue impacting the entire street resolved. I'm convinced that the support script is titled "WAR OF ATTRITION" and is specifically designed to get the customer to give up and quit reporting it.
Also, if anyone would like a visual representation of what these outages look like, here's a graph:
Why are the outages showing as spikes in the chart, as opposed to gaps? Well, that's because the service has gotten so bad that I rigged up a system to fail the entire house over to a Verizon hotspot when it happens. At least that stays up.
(edited)
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TaperCrimp
Visitor
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13 Messages
3 years ago
4 outages today and it's only 12PM ET. The line techs were out again and attempted more rewiring for the entire street. There seems to be zero methods for relaying this information to the line techs, and instead I'm perpetually stuck dealing with the front-level tech support that makes me go through the exact same troubleshooting steps over and over.
I used to envision the biblical Hell consisting of a shopping mall filled with Apple Stores and staffed by people that write RFPs and RFIs for a living. At this point I believe there's a worse eternal punishment.
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jblucher14
Visitor
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1 Message
3 years ago
ditto. been having this issue for weeks and they (Comcast Support) are no help, but more of a frustration. I don't know, I been a customer for decades, but I think it's "Time" to move on to a more customer oriented company.
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macrhino1
New Poster
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11 Messages
3 years ago
Yes, he should hijack someone else's help thread. Maybe we can get Comcast to start taking these problems seriously.
I am a network engineer who consulted with CERN in the specification of the World Wide Web in the 1980s. I brought the country of Kuwait online in 1994 with the first public ISP in the Middle East. I now run a company that builds high-speed Internet distribution systems around the world (Mostly outside the US but we do have a system in Albuquerque NM) and maintains a NOC for DELL. I have had a DHCP problem for over a year at home and have yet to reach anyone in Comcast who even understands the problem. The level of networking knowledge of the technical help staff of Comcast is similar to a power user at home.
I have an Arris S33 cable modem (Which is a level 1-2 device except to access some basic configuration screens). It connects the Comcast network to a local network at that level. It does not have "modes" and it is a recommended device from Comcast. I have a problem getting consistent DHCP leases from the Comcast server. Here is a response from Comcast Technical support:
"I'm sorry - to clarify, our DHCP server is set to send an IP to a modem, itself. Your MicroTik router from earlier is a subnetting issue and beyond the demarcation of a residential ISP.
The technician noted that the resolution of the troublecall was for home networking, and our networking engineers would be unable to assist. As a residential ISP we're not able to help with this. I would reach out to support from MicroTik, as our DHCP servers are only assigning external IP addresses to the modem on the account, and your router deals with any subnetting lease times within the scope of residential services. DHCP lease request is client side. If the registered modem on the account is getting the IP, then that's as far as Comcast is able to go on the residential services. I do see that a myriad of agents have tried to assist in the scope that we're able to help with, and even then, our engineering team is not able to assist with subnetting. "
Now the technician they sent against my advice, said: "this problem is way way above a technician's ability to solve, I have no idea why they sent me." Comcast still wanted to charge me 100$ for the tech visit I told them was unnecessary. After speaking to a supervisor and supplying the text message where the Support tech said they would waive the charge, Comcast reversed the charge explaining still that "It was a valid charge".
So Comcast technical support believes my level 2 device is getting an IP address from the DCHP server. This response is after over 50 pages of back and forth with technical support. And my inability to CONSISTENTLY get an IP lease (I do get them, just not consistently) from the DHCP server is a "Subnetting issue" which leads me to believe the tech here is dropping technical terms and thinking the customer will not know better. Keeping in mind that this customer (me) runs a company with a network operating center providing monitoring and control to 300+ networks around the US. That system has static addresses from Comcast and we do not face the problem there, only my home network has the problem.
I have the highest level of service offered to residentials in my area which is supposed to be 1.2 Gbps. What is the offered solution to my problem?
Comcast:
"I'm sorry that we've reached an impasse here, but if there's anything further my team and I can answer, I'm happy to do so! Once again, we really think a business account would better fit your needs, as those accounts are equipped to handle further dives into the demarcation that you're seeking. Let me know if you have any further questions."
I can sign up for a business account (an increased cost of 200% for equivalent service) to fix my home technical problems. Keep in mind, my problem is that the DHCP server is not allowing my router, AN ISP CLASS ROUTER, to renew IP leases. When the "Tech" asked about my wifi, I explained that my hot spots (8 of them) are all in bridge mode and operate as two MESH networks. I have no problems in the local network at all which is a /22 net due to the number of devices I have on the net. My only problem is not getting a timely DHCP lease.
Here is the comment previous to the quoted one above:
"When a modem is in bridge mode, the Static IP routing, LAN DHCP and other settings are disabled. A bridged modem will only assign dynamic public IPs to connected devices in the same manner as a basic cable modem. I know you are very technical so you are likely already aware of this. I believe your current setup would work better with our business services and not our entertainment internet offering. However, I do realize there can be a different need for everyone out there and you have already stated you would not prefer to change that set up. I also see we've mentioned already that we typically do not support home networking equipment owned by you and in a situation where service is being pushed to the modem, that appears to be working and would be the extent of our support options. "
Here is the worst part, Comcast told me to contact Arris about the problem. After reviewing the "help" I got from Comcast, the Arris tech said, your modem is working properly but Comcast has no idea what they are talking about.
I am able to work around the problem I have by hand-coding IP addresses and a default route into the router. Then I can get download speeds of up to 1 Gbps. This will be successful until there is a major reconfig at Comcast where I will have to wait until I can get a DHCP lease (Which will typically range from 4 days to 1 hour) and this provides me with the information I need to reconfigure the router when the lease renewal fails.
In many pages of chat text, I found one support tech that asked for a TCP dump (A step in the right direction) but by the time I could supply it, it had shifted to a different tech who could not parse it. Keep in mind here that my router (Mikrotik RB4011) is capable of DHCP logging to the DEBUG level, something I have both pointed out to the support staff and once provided to them.
Keep in mind, all I have asked for is the DHCP to provide a renewed or new lease when the old one expired. Fully cognizant that the problem could be on my side, I only wanted someone on the other side of the connection to troubleshoot this with me. This has not happened. I was informed that I was asking for too much.
"Ok, I have an update! I touched base with my support team, explained the situation, and had them read everything over. The general conclusion was that the residential system is working as intended, and that the current ask is outside of what residential services can provide--and you'd be more suited with having a business service installed as a home-based business account, as that can provide the features you need for this particular instance. There are technical and network restrictions when it comes to residential internet services: https://comca.st/37fDD2F"
So maybe if they get enough pressure on their forums, they might start giving their support staff the privileges and training to handle problems like this.
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