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Intermittent Connection Issues [T3 and T4 Timeout]

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Frequent Visitor

Intermittent Connection Issues [T3 and T4 Timeout]

Good evening. I figured I would take to the forums in a hope to get a better answers or a more experienced opinion. Twice now I have gotten the run around answer from the live chat lines about monitoring my account and a call back if anything was detected, which was never done. With the second call, the modem restarted due to a T3 timeout not 20 minutes after speaking with them.

 

Upon moving to a new address I have started experiencing horrible internet connectivity. I tried calling and explaining what was found in the event logs, but the operators I spoke to each time did not even acknowledge the information and proceeded to (what it seemed like to me) read from a list of responses. I'm not sure if that is actually how it works, but the answers were quite similar about just monitoring and nothing they could do at the current time.

 

After the second call, I have since replaced my modem and this is still happening many times a day at random intervals. The modem and router and near brand new and are different brands then what I had before.

 

If anyone has any opinions on what I should say to customer support if I have to make another call or if this can be resolved through the more experienced teams fielding the forums, that would be amazing.

While I know due to the times that everyone is struggling, I find myself quite saddened by the fact that the customer support teams would not even listen to what I had to say or acknowledge the fact that I believe it is not an issue that can be fixed from behind the desk or myself.

 

If anyone needs any futher information or would like me to try anything specifically, please feel free to let me know.

 

Modem Model: CM500-100NAS
Router Model: VLP0101B (VELOP AC1200 Mesh Node Wifi 5 Network / Black)

 

Startup Procedure
ProcedureStatusComment
Acquire Downstream Channel627000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnabledBPI+
IP Provisioning ModeHonor MDDhonorMdd(4)
Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25625627000000 Hz-7 dBmV41 dB183410
2LockedQAM25617579000000 Hz-6 dBmV41.7 dB192461
3LockedQAM25618585000000 Hz-6.3 dBmV41.6 dB178369
4LockedQAM25619591000000 Hz-6.3 dBmV41.4 dB238429
5LockedQAM25620597000000 Hz-6.4 dBmV41.3 dB176460
6LockedQAM25621603000000 Hz-6.3 dBmV39.8 dB167345
7LockedQAM25622609000000 Hz-6.3 dBmV40.7 dB196514
8LockedQAM25623615000000 Hz-6.4 dBmV41.5 dB175469
9LockedQAM25624621000000 Hz-6.8 dBmV41.2 dB217613
10LockedQAM25626633000000 Hz-6.8 dBmV41 dB214569
11LockedQAM25627639000000 Hz-6.6 dBmV40.9 dB181301
12LockedQAM25628645000000 Hz-6.6 dBmV41.2 dB154383
13LockedQAM25629651000000 Hz-7.1 dBmV40.8 dB137449
14LockedQAM25630657000000 Hz-7.1 dBmV40.9 dB146541
15LockedQAM25631663000000 Hz-7.4 dBmV40.7 dB145303
16LockedQAM25632669000000 Hz-7.4 dBmV40.6 dB153413
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA45120 Ksym/sec15700000 Hz51.5 dBmV
2LockedATDMA15120 Ksym/sec34900000 Hz52.3 dBmV
3LockedATDMA25120 Ksym/sec28500000 Hz51.5 dBmV
4LockedATDMA35120 Ksym/sec22100000 Hz52.8 dBmV

 

Extended Upstream Transmit Power
(Enabled) Enable Extended Upstream Transmit Power

 

Current System Time:Wed Aug 12 18:06:37 2020
System Up Time:00:26:43

 

TimePriorityDescription
2020-8-12, 17:49:22Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:01:13Notice (6)Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:28Critical (3)No Ranging Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:22Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-12, 17:35:19Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 17:35:15Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 17:35:15Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 17:25:05Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 16:38:40Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.0;CM-VER=3.0;
2020-8-12, 16:38:14Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 16:31:34Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 16:31:10Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-12, 16:31:10Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-11, 16:22:52Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-11, 13:10:33Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-11, 13:10:33Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
2020-8-11, 08:18:11Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:28Critical (3)No Ranging Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:21Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:26Critical (3)No Ranging Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:21Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-10, 17:47:44Critical (3)No Ranging Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.0;CM-VER=3.0;
2020-8-10, 17:47:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-10, 17:47:35Critical (3)No UCDs Received - Timeout;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-10, 17:47:18Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:01Critical (3)No Ranging Response received - T3 time-out;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:01:5c:88:4a:4b;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:53Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:51Critical (3)No UCDs Received - Timeout;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:34Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:24Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:24Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:20Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=44:a5:6e:83:91:48;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
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Frequent Visitor

Re: Intermittent Connection Issues [T3 and T4 Timeout]

Another snapshot, as the modem was only on for a short time when it was taken and had just finished having issues.

 

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25625627000000 Hz-5.5 dBmV41.1 dB210508
2LockedQAM25617579000000 Hz-4.3 dBmV41.8 dB273557
3LockedQAM25618585000000 Hz-4.6 dBmV41.7 dB207501
4LockedQAM25619591000000 Hz-4.7 dBmV41.5 dB287534
5LockedQAM25620597000000 Hz-4.7 dBmV41.5 dB230621
6LockedQAM25621603000000 Hz-4.7 dBmV40.2 dB243439
7LockedQAM25622609000000 Hz-4.7 dBmV41 dB254649
8LockedQAM25623615000000 Hz-4.9 dBmV41.5 dB260569
9LockedQAM25624621000000 Hz-5.3 dBmV41.3 dB261772
10LockedQAM25626633000000 Hz-5.3 dBmV41 dB275760
11LockedQAM25627639000000 Hz-5.1 dBmV40.9 dB235386
12LockedQAM25628645000000 Hz-5.1 dBmV41.2 dB218493
13LockedQAM25629651000000 Hz-5.7 dBmV40.9 dB179563
14LockedQAM25630657000000 Hz-5.7 dBmV40.9 dB208636
15LockedQAM25631663000000 Hz-6 dBmV40.7 dB199387
16LockedQAM25632669000000 Hz-6 dBmV40.6 dB200565

 

Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA45120 Ksym/sec15700000 Hz49.8 dBmV
2LockedATDMA15120 Ksym/sec34900000 Hz50.5 dBmV
3LockedATDMA25120 Ksym/sec28500000 Hz50.3 dBmV
4LockedATDMA35120 Ksym/sec22100000 Hz49.3 dBmV
Highlighted
Frequent Visitor

Re: Intermittent Connection Issues [T3 and T4 Timeout]

I was able to get on the actual live chat. I spoke to the wrong department originally, and they were super understanding and willing to help. As soon as I was transferred I got to the script reader who refused to listen to anything discussed or even look the forum attached. Up to the point of telling me to unplug the router for the network I was attached to and talking to him on, then tell him when it was unplugged after...

 

I guess I will post an update if the issue persists, but at that point I will likely demand to be escalated to someone who will listen to me. I do not understand how provisoning the modem now three times would change the outcome of the previous provisioning.

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Expert

Re: Intermittent Connection Issues [T3 and T4 Timeout]

The upstream power is too high 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, latency problems, and the un-bonding of channels.

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.


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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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Frequent Visitor

Re: Intermittent Connection Issues [T3 and T4 Timeout]

Thank you for the reply @EG, I have already tried these troubleshooting steps and I have the minimum number of connections (literally just one cable, no splitters) from the modem to wall, and have tried both the Xfinity provided cables for self installation I obtained originally. 

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Expert

Re: Intermittent Connection Issues [T3 and T4 Timeout]

Ok if nothing applies, then as stated, you will need a tech out to investigate / correct the problem.

 

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 !



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
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Frequent Visitor

Re: Intermittent Connection Issues [T3 and T4 Timeout]

Thank you very much @EG, I got on live chat once more and finally got a technician scheduled after getting a bit more snappy then I would have liked at the live chat person. I found no point in doing the exact same reprovisioning steps for a fourth time, when he did not see the same my way.

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Expert

Re: Intermittent Connection Issues [T3 and T4 Timeout]

Quite welcome !



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!