I have been having T3 timeouts over the course of 3 years. They happened in August 2018, August 2019, and now June 2020. In the past Comcast checked home wireing (all ok,) replaced the wire from the box on the house to the pole and a connection at the top of the pole. None of these fixed the problem. Since it was so intermittant, they never took me seriuosly and they didn't come out for a followup.
The problem seems to be tied to very high temperatures. As soon as things cooled down a little there were no more time outs until the next year when it got hot again. Today was an extremely hot day and the T3s started up again.
What should I do or say to get them to get a line man to come out and check the old wiring on the poles in our alley? I am convinced that is where the problem is. A repair person said a line man should come out, but I could never get that to happen when I called Comcast.
If anyone wants to see my modem logs, I can provide them.
Thanks for any and all help.
Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.
I can't post a screen shot, so here is just the numbers you asked for. Let me know if you need more.
Signal to Noise Ratio: Channel ID 4-11 = 38 db
Power Level: Channel ID 4-10 = 0 dBmV, Channel ID 11 = 1 dBmV
Power Lever: Channel ID 4 = 49 dBmV, Channel ID 3-1 = 48 dBmV
Since you are a new poster, it needs to be approved by a Forum Admin. That could take some time. In the interim, you could try hosting it at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to it here.
Or copy all of the text of the status page and paste it into the body of your next post here.
Let's see if this works.
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.
All in house connections where checked by Comcast tech. and or replaced in 2018 and 2019. There are no splitters. Only one connection (to extend the cable) in the house (that was checked/replaced by Comcast.) All outside connectors (the box and the ground wire and the cable to the pole and the connector at the pole) were replaced by Comcast. All of these checks/replacement happened either in Aug 2018 or Aug 2019.
Thanks for taking the time to look over my information. I will try to set up an appointment.
Quite welcome ! Good luck with it !
Contacted Comcast. First thing they did was to offer me a better rate if I signed a one year contract. Then they had to send me to another agent. Was waiting for an hour. 2nd agent said that they were not sending people out (due to the virus) and my signal looks good. Also, since it is my modem there is nothing that they can do and I should check with the modem manufaturer. I checked the Arris page (SURFboard SB6141) and there are no updates (or anything at all) available for my modem.
I had so many unanswered questions and she kept saying there was nothing they could do. Great. Not sure what my next steps will be.
Keep on them. Good luck !
Comcast said to follow up with my modem manufacturer and I did via the web.
From this link on the modem manufatures page, I checked all the modem's reported values and they were all in spec.
This next link says there are no drivers or firmware available for my modem.
That makes sense as this page describes how the cable company is responsible for doing modem firmware updates.
That is interesting because it means that Comcast has more control over the modem I own than they eluded to. So now I know that they can 1. remotly flash the modem and 2. they can remotly reboot it. Can they also read my logs and just told me they couldn't?
In the past, when calling Comcast, I was told they could read my modem logs (I own the modem) to verify a problem I was reporting. Currently, they are telling me they cannot read the logs since it is my modem and therefore they can't help me with my issue.
If they can't read the logs, fine, then I won't keep persuing that. If they can, I need to keep calling till someone admits they can and actually looks at the logs to verify what I am telling them.
The problem involves T3 time outs and I'll be keeping my main post up to date.
There was only 1 T3 time out yesterday (not enough to elevate to a T4 as happened multiple time a few days ago.)
Would it be better for me to present this to Comcast as a T4 problem? A T3 may cause a pause, but really it is the T4 (reboot of the modem) that really causes bad disruptions in my workflow.
There was only 1 T3 time out yesterday (not enough to elevate to a T4 as happened multiple time a few days ago.)
FWIW, it doesn't "elevate" from a T3 to a T4 error, they are two separate and distinct types of errors. T3's indicate an upstream / return path impairment. T4's indicate a downstream / forward path impairment.
Would you help me understand this?
After a sufficient number of T3 errors such as
Ranging Request Retries exhausted
Unicast Maintenance Ranging attempted - No response - Retries exhausted;
No Ranging Response received - T3 time-out
I then get:
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Then I get a reboot with this:
Cable Modem Reboot due to T4 timeout
Would it help to post a screenshot of the log file?
3-Critical R2.0 No Ranging Response received - T3 timeout:
Explanation. The cable modem has sent 16 Ranging Request (RNG-REQ) messages without receiving a Ranging Response (RNG-RSP) message in reply from the CMTS. The cable modem is therefore resetting its cable interface and restarting the registration process. This typically is caused by noise on the upstream that causes the loss of MAC-layer messages. Noise could also lower the signal-to-noise ratio (SNR) on the upstream to a point where the cable modem's power level is insufficient to transmit any messages. If the cable modem cannot raise its upstream transmit power level to a level that allows successful communication within the maximum timeout period, it resets its cable interface and restarts the registration process.
Recommended Action No action is needed if this is an occasional problem. Check the upstream transmit power for the cable modem to see if it is at or near the maximum allowable levels. Check the RF plant for cabling or connector issues that could generate sufficient noise to lose MAC-layer management messages.
3-Critical H501.8 HFC: T4 Timer Expired:
Explanation. The cable modem did not receive a station maintenance opportunity in which to transmit a Ranging Request (RNG-REQ) message within the T4 timeout period (30 to 35 seconds). The cable modem is resetting its cable interface and restarting the registration process. Typically, this indicates an occasional, temporary loss of service, but if the problem persists, check for possible service outages or maintenance activity on this particular headend system.
Recommended Action for your Provider: Check the configuration on the CMTS. Check the cable plant for RF connector or cabling issues that could be generating noise on the downstream.
What is the most effective way for me to report this to Comcast so they will help? Do I report it as a T3 problem or a T4 problem or both? Is it best to play dumb or do I share what I know about the problem?
I need to plan my stratagy. Although there have been no issues since June 4, I bet they will start up again the next really hot day we have here.
The problem is happening more often. I wish the service would completely die so I could get someone from Comcast to help!
The log files are filling up now due to the larger number of errors. I wrote a script to collect the log files. As long as I keep the computer up and running I'll be able to have a basically unlimited history of log entriesnow . I also realized that the first signal of trouble is not being able to ping the modem. I am recording that along with what comes from the modem logs.
The script is paying off. I can see how much more the problem is happening now. At one time (Monday afternoon,) the modem rebooted but never reconnected. The "online" light was off (meaning no connection.) Called Comcast, they tried to reboot the modem, it obviously failed. They set up an appointment for me on Wednesday. About an hour later they texted me saying they had fixed a problem in my area. I rebooted the modem and everything worked. They also asked if I wanted to cancel my appointment. I cancelled it because I didn't want to be charged if they came out and there was no problem.
I don't know if the problem is fixed or not. I'll have to keep monitoring the logs. In the last 12 hours there have been four T3 timeouts, no other errors, no reboots and only one ping failure. My script is doing pings to the modem and log monitoring/collection every minute.
I'll keep posting until this gets resolved in hopes someone else can benefit from all this. I am currently not too optimistic that things have been fixed. I would love to be wrong about that.
The problem persists. On Wednesday I called Comcast and actually got an appointment for them to call me on Saturday. Based on that call they *might* set up an appointment for someone to come out and look at things.
Later in the day (Wednesday) the errors were happening less often. Thursday and Friday (so far) there were only four t3 errors, no modem reboots and nothing else in the logs. Without an explanation why there are now fewer errors, I can't believe that this issues is fixed. After 3 years off and on, it certainly didn't fix itself.
For what it is worth, a cool front came in Wednesday afternoon and it has been cooler since then. That goes along with my theory about this problem possibly being heat related.
FWIW, higher ambient temperatures creates more resistance in the lines which amounts to higher upstream power levels and lower downstream power levels. There are AGC (Automatic Gain Controls) In their line amplifiers on the poles but sometimes these are purposefully disabled by their line / maintenance techs for their own reasons or they are malfunctioning.
Comcast tech. did not call Saturday evening as the last person I talked to said they would. Instead I got an automated call setting up an appointment for Sunday evening.
Tech came out Sunday and couldn't find a problem. I told him it was intermittent. He said he would write it up as a "line call, non customer impacting" since he had no evidence of a problem. He gave me his supervisor's number. I called and left a message with my number asking to be contacted if I could provide any more information to help in any way.
There have been no issues in the log file at all for the last 48 hours at the time I am posting this. Once again I am predicting the problem will come back with hot weather. If the forecast holds up, that will be near the end of this week.
I'm definitely following your saga as it's very similar to mine. I haven't found a temperature correlation yet, but the t3 timeouts are exactly what I'm seeing and I'm having trouble getting any level of support beyond, "let me send a refresh signal".
As was forcast, the temperature got hotter around here. Although I did see more errors as the temperature rose, I saw far fewer than before. In the last week I've seen about nine T3 errors, two T4 errors and one modem reboot. The majority of those happened on Friday and Saturday. The reboot happened Saturday and no errors have been logged (so far) today, Sunday.
Maybe there are mutlitple problems along the line and they fixed the biggest one. I hate intermittant problems.
I'll still keep monitoring the modem and reporting back here.
Well, well. Woke up this morning to see and additional ten T3s, four T4s, and 2 reboots. So much for the problem being solved.
It is starting to appear that the heat issue might be a cumulitive one.
Here is how I started tracking my T3/T4 issues for the last 18 days. I've put the high temperature for the day on the graph to see if there is any correlation between higher temperatures and issues. Either way, just the T3 and T4 data by itself may be usefull to have.
Following your thread. I have an Arris Surfboard SB6190, live in Michigan. Everything was fine over the winter, but I've been getting increasingly frequent T3 and T4 timeouts as the temperature has increased. Connection drops on average 3 times a day now for 5-30 minutes.
Replaced RG59 coax with RG6 and removed splitter and the problem persists, although my downstream power levels went from 2 dBmV to 11 dBmV.
Downstream channels 256QAM; power level 11.2 +/- 0.3 dBmV; SNR 38.9 +/- 0.3 dB
Upstream channels ATDMA; power level 36.5 +/- 0.5 dBmV
Afraid to start the process of engaging Comcast and having the burden of diagnosis left completely to me, like it has been for rwkeating.
1) I was considering creating a script like keating has done. Is historical data like this useful to Comcast support/techs, or will it be ignored?
2) Is there equipment I could invest in to troubleshoot connectivity myself? I'm a network admin by profession but all Cisco LAN technologies, no ISP experience. It's very frequent that friends, family, or myself have intermittent issues with cable internet.
I don't think my data collection will be looked at or make a difference to Comcast. I am collecting the data so that I might learn more about the problem. If for example, I knew say a time of day when the problem was more likely to happen, that would be a good time to call Comcast in hopes that they would see it. The problem has been occuring infrequently enough (so far) that it hasn't figure in to when I call them. If they can't see/document the promblem from their tests, we are left completly on our own.
I followed your issue (I've been experiencing the same problem). Just posted my own problem with my modem-router's most recent data (only one instance, though): https://forums.xfinity.com/t5/Your-Home-Network/Intermittent-T-3-T-4-and-MDD-Timeouts-Please-fix-our....
I live in a very hot area, so your heat theory seems very plausible to me.
I still see how heat could cause such a problem, but in my case I am not seeing the data (so far) to back up my idea. Maybe they fixed something. For almost that last 5 days I have had no errors in the logs and the high temps have been from about 85 to 91. I wonder if they really did fix something. Only time will tell.
Hey, I've been following this thread as well and having consistent T3 and T4 timeouts. I've exhausted every option Comcast has given me with the issue, including live tech support as well as over the phone. In the end, they told me they had no one they could send out to fix the issue, and so I'm stuck in the same boat as some of you. Has anyone gathered any more information about what can be done?
Here is an idea. Depending on how friendly you are with your neighbors, ask them if they have Comcast and if they have had any temporary short term outages. If they aren't tech savy, they may not know or be able to descern between a slow/down website and a cable outage. If you know them well enough, you could offer to look at their modem logs. If they are having T3s (and especially if those coincide with yours,) you could get them to call Comcast when you see the problem (as they are most likely seeing a problem at that time also.) If enough people in an area call at the same time, maybe Comcast will listen and do something.
I don't have neighbors that I am that friendly with, but my idea may work for others. Good luck.
I've had this problem in the past back in 2016. I am experiencing the same issue now that I am working from home due to COVID, hence the reason why I got to this thread. Right now, I am getting the same 3 Log entries below about every 10 miinutes.
Here is another idea you may want to try with Comcast/Xfinity, which I did in 2016 since I too own the Arris Motorola SB6141 modem.
|Aug 02 2020 07:47:04||3-Critical||R02.0||No Ranging Response received - T3 time-out;CM-MAC=##:##:##:##:##:##;CMTS-MAC=##:##:##:##:##:##;CM-QOS=1.1;CM-VER=3.0;|
|Aug 02 2020 07:45:04||3-Critical||R06.0||Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=##:##:##:##:##:##;CMTS-MAC=##:##:##:##:##:##;CM-QOS=1.1;CM-VER=3.0;|
|Aug 02 2020 07:45:04||3-Critical||R03.0||Ranging Request Retries exhausted;CM-MAC=##:##:##:##:##:##;CMTS-MAC=##:##:##:##:##:##;CM-QOS=1.1;CM-VER=3.0;|
|Signal to Noise Ratio||37 dB||37 dB||37 dB||37 dB||38 dB||37 dB||37 dB||37 dB|
|Power Level |
|5 dBmV||5 dBmV||5 dBmV||4 dBmV||4 dBmV||4 dBmV||3 dBmV||4 dBmV|
|Symbol Rate||5.120 Msym/sec||5.120 Msym/sec||5.120 Msym/sec||5.120 Msym/sec|
|Power Level||38 dBmV||36 dBmV||37 dBmV||38 dBmV|
Was Comcast immediately receptive to the problem once you had rented one of their modems and reproted the T3 problems or did you still have to fight with them?
I continue to have issues and I am still tracking them. I've dropped the temperature data from the graph as I see no correlation at this time. I still think I will see a reduction in T3/T4 issues come fall and winter, but only time will tell. Here is a graph of my data so far.
I am going by memory since it was 4 years ago but not really that they were more responsive . They just had to keep doing the troubleshooting since the modem was theirs. All they could tell me is that everything looked fine. I think I remember changing the switch and the splitters.
This time, I am planning on replacing the RJ-45 connectors first since the locking tabs are gone. Maybe the wire is comming lose. If that does not helph I'll change the switch.
I replaced the switch and the connectors that day on 8/2/20. Today, two days later, I do not see any T3 messages in the log page. Everything appears to be working fine. As a matter of fact I see no new messages of any type since 8/2/20. The last log entries are related to me rebotting the modem.
|Aug 02 2020 22:40:26||5-Warning||Z00.0||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=#;CMTS-MAC=#;CM-QOS=1.1;CM-VER=3.0;|
|Jan 01 1970 00:00:22||3-Critical||R02.0||No Ranging Response received - T3 time-out;CM-MAC=#;CMTS-MAC=#;CM-QOS=1.1;CM-VER=3.0;|
|Jan 01 1970 00:00:18||6-Notice||N/A||Cable Modem Reboot due to power reset ;CM-MAC=#;CMTS-MAC=#;CM-QOS=1.1;CM-VER=3.0;|
I would like to post our experience with the same problem here.
Since we moved into this house last year, we have been suffering the same T-3 timeout problem.
To show how crazy the frequency is:
We asked the technician to come in Feb. 2020, and the person checked all the signals and claims things are OK. He claimed that the problem is probably our modem, which had been working perfectly before we move (we also used Comcast's service in that property). We purchased a new modem, still suffered from the problem, that every now and then it spontaneously disconnects and we had to reboot the modem. Most of the times, rebooting works, but there were times things were pretty bad. We complained to Comcast in April, and they asked us to rent their modem. We did, for two months, the problem is still there--when our modem can't connect, Comcast's modem can't neither.
In between Feb and Aug, I searched numerous discussions on the online forums and got to the conclusion that "it is very hard to find out where the problem might be". The problem is so intermittent and hard to troubleshoot.
After the fall semester starts, probably due to the high internet traffic here in this small town (online learning), we started to experience much severe intermittent disconnection. It breaks every 10-15 minutes, and kids couldn't even use the internet for the online school.
We complained to Comcast again, and this time, a more experienced person came.
This person didn't say much but simply went to cut off the old connectors and reinstall the new ones. He did that at the tap, at the boxes outside and inside our house.
Guess what? It has been a month, and we only saw two T-3 timeout error messages.
We didn't even experience disconnection when those two errors were incurred.
The signal strength of the upstream channels also stabilized significantly.
I can't believe the solution is this simple.
My suggestion is to order a tech over and bug him/her to replace all the connectors, if this troubleshooting step has never been performed.
All the connectors in the house, outside at the box and going up the pole have been replaced. There is just one piece of cable that hasn't been replaced (the one that goes from the box into the house.) Maybe I can get them to replace that next time.
I continue to track the problems. Here is an updated graph.
For what it's worth, I'll document my experience after having suffered and reported the same intermittent disconnection (T3/T4) problem (in another thread here) that started abruptly in January 2020 after a long outage in my area.
After a couple of tech visits that I requested by myself, the "techs" looked all around the house and tried very hard to pin the problem on my home - through illogical attempts. One of them tried to get me charged their "service fee" for fixing the home wiring - and I had to call Comcast to reverse the charge, by asking them to provide evidence of their work on home wiring (obviously they had none) and pointing out that the problem wasn't fixed either.
Thereafter, a quite technically competent and genuinely helpful Comcast tech I found on this forum helped by schedule the following tech visits when one of the techs was successful in reducing the frequency of the problem from twice very day to once every 2-3 days. He worked completely on Comcast infrastructure outside my home, however he couldn't nail down the root cause, so suggested renting a Comcast modem during his visit to troubleshoot the issue. Given my knowledge from this forum, I was fairly certain my modem wasn't the problem, so I had declined. The follow-up tech visit simply blamed my modem and home-wiring again - even after I told him that the prior tech had helped reduce the frequency of the problem and must've been on the right track. This tech instead tried to argue that the problem was my modem or home-wiring or both.
After 5 tech visits, I was fairly exasperated to the point that I requested the forum-found tech to just let it be, because I couldn't handle the incompetent tech visits any more. I decided I'd just live with the problem, if it happened once every 2-3 days.
Thereafter, I decided to try a bandpass (MoCA Input blocking) filter that allows in 5 - 1002 MHz and attenuates 1125 - 1525 MHz. For good measure, I also added a forward (+10 dB) and return path (+10 dB) amplifier - even though the modem log suggested that one was not needed when connection was stable. I had +10 dbmV downstream and +36 dbmV upstream signal levels on my modem - though the downstream signal varied considerably through the day and significantly degraded whenever the intermittent disconnection happened (so the degradation was almost certainly what triggered the disconnection). Regardless, the total cost for me was less than $ 25 from Amazon, so I had little to lose by trying - given that working from home requires me to have a stable connection.
For the last 12 days or so, I have had zero disconnects, zero modem log warnings, or any critical messages in the modem log (with same old personally-owned modem of 4 years). Keeping fingers crossed, but I think the bandpass filter was the key to solving my 9-month long misery, especially while working from home. In case, it helps someone, I figured that I'll document it here.
I wanted to put this in my original thread, but I guess after time you can't reply anymore so I am starting this new one.
Edited to cross out the above line as someone was nice enough to put this back in my main thread. Thanks!
Here is an update on my T3/T4 tracking. In the last few days, the counts went through the roof. T3s were as follows: Fri 49, Sat 407, Sun 502, Mon 157. The flood stopped on Monday and there has only been one T3 since that time.
A few thoughts:
1. I wonder how/why this got corrected? Did someone call or did Comcast actually see this issue?
2. Will their correction fix the problems I've been seeing for the last few years?
3. Funny that with 1000+ T3s, not once did any of them escalate to a T4 as they often did in the past.
4. Ignoring this exception in the data, the initial data still fits my idea that T3/T4 get worse in the warmer weather months. Have to keep tracking to find out for sure.
The spikes I started seeing in January have continued off and on. I am still suprised (and pleased) that there have been no T4s during this time, but this number of T3 is still very troubling.
Although there have been days with T3 counts above 200, I've only increased the range of the graph to 200 to keep the lower count bars readable.