Question Intermittent Drops in Internet Connection

Mar 30, 2022
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Router: Asus RT-N66U (latest firmware)
Modem: TP-LINK TC-7620 (DOCSIS 3.0)
VoIP: ARRIS TM822G
ISP/Connection Type: Suddenlink Cable (400mbps dwn / 30mbps up).
Devices Connected: We have 20 items in total connected to our router. 15 on the 2.4GHz . 3 on 5GHz. And 2 that are wired. I've attempted to plug directly into the router with the same issue. 5 computers are connected to our router. (1 work, 3 personal). Other devices are ipad / iphone / android / roku / nvidia sheid / smart plugs & lights

Last week, after tornadic weather activity in our area, our internet was down for two days. In talking with Suddenlink's technical support, they had me power-cycle all of my network devices, direct connect a laptop via cat5 ethernet to the TP-LINK modem to run speed tests (0mbps), and finally reset the TP-LINK modem, after which it would no longer obtain internet.

Suddenlink dispatched a technician and then called staying they were seeing a signal issue throughout our area, that they would be able to resolove the issue from outside our home. The internet did come back up eventually that afternoon. Speed tests showed normal.

The following day, web browsing (egde, chrome, firefox) were all extremely slow. Speed tests did not reflect slowness on download, but upload was .01mbps. Resetting devices did not result in and increased performance. I have no hubs / switches. Plugging directly into the modem and running a ping -t 8.8.8.8 - packet were dropping.

I contacted Suddenlink & they tried to sell me their rentable modem to resolve the issue. I asked for a technician. The tech came yesterday said our signal was great into the house and stable at ~400mbps. He said that if it were too high or too low, it could cause the packet loss issues. He said he's been seeing other DOCSIS 3.0 modems having this issue after the weather outage. He said because of the newer faster internet speeds with new channels that my 3.0 router doesn't support - it's causing the issue and that I would need to buy a 3.1 DOCSYS modem to resolve the issue.

TP LINK support said to buy a new modem.

Looking at the Error log on our Router I'm seeing a lot of errors. Posted the log below.


TimePriorityDescription
Wed Mar 30 19:40:38 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Wed Mar 30 14:57:22 2022Notice (6)TLV-11 - unrecognized OID;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Wed Mar 30 14:57:21 2022Error (4)Primary address failed, secondary active;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Wed Mar 30 14:57:21 2022Warning (5)DHCP WARNING - Non-critical field invalid in response ;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=...
Wed Mar 30 14:58:37 2022Critical (3)DHCP failed - RS sent, no RA received;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.0;CM-VER=3.0;
Wed Mar 30 14:58:20 2022Notice (6)Honoring MDD; IP provisioning mode = APM
Wed Mar 30 14:58:10 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:00:00:00:00:00;CM-QO...
Wed Mar 30 14:58:10 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:00:00:00...
Wed Mar 30 14:55:40 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:00:00:00:00:00;CM-QO...
Wed Mar 30 14:55:39 2022Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=98...
Wed Mar 30 14:55:39 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Wed Mar 30 14:55:15 2022Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=98...
Wed Mar 30 14:55:15 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Wed Mar 30 14:54:46 2022Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=98...
Wed Mar 30 14:54:46 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Wed Mar 30 14:54:44 2022Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=98...
Wed Mar 30 14:54:44 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Wed Mar 30 14:52:13 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Wed Mar 30 14:52:13 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Wed Mar 30 14:52:06 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Wed Mar 30 14:52:06 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Tue Mar 29 10:23:03 2022Error (4)DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VE...
Sun Mar 27 22:26:00 2022Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;...
Sun Mar 27 22:25:53 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Sun Mar 27 22:25:36 2022Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;...
Sun Mar 27 22:25:32 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Sat Mar 26 12:14:26 2022Error (4)DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VE...
Wed Mar 23 16:29:19 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QO...
Wed Mar 23 16:29:17 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Wed Mar 23 16:29:17 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QO...
Wed Mar 23 16:28:42 2022Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8...
Wed Mar 23 16:28:40 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;

ProcedureStatusComment
Acquire Downstream Channel567000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
Configuration FileOK^1/77FB7FF4/TYPE=RES/COS=194/IP=2
SecurityEnabledBPI+
Downstream Bonded Channels

ChannelStatusModulationChannel IDFrequencyPowerSNR
1LockedQAM2562567000000 Hz-1.8 dBmV39.5 dB
2LockedQAM2561561000000 Hz-2.4 dBmV39.3 dB
3LockedQAM2563573000000 Hz-1.6 dBmV39.5 dB
4LockedQAM2565585000000 Hz-0.9 dBmV39.2 dB
5LockedQAM2566591000000 Hz-0.5 dBmV39.5 dB
6LockedQAM2567597000000 Hz-0.2 dBmV39.6 dB
7LockedQAM2568603000000 Hz0.0 dBmV39.6 dB
8LockedQAM2569609000000 Hz0.3 dBmV39.7 dB
9LockedQAM25617657000000 Hz0.6 dBmV39.4 dB
10LockedQAM25618663000000 Hz0.6 dBmV39.4 dB
11LockedQAM25620675000000 Hz0.7 dBmV39.2 dB
12LockedQAM25621681000000 Hz0.6 dBmV39.3 dB
13LockedQAM25622687000000 Hz0.8 dBmV39.4 dB
14LockedQAM25623693000000 Hz0.6 dBmV39.4 dB
15LockedQAM25624699000000 Hz0.5 dBmV39.3 dB
16LockedQAM25625705000000 Hz0.5 dBmV39.3 dB
Upstream Bonded Channels

ChannelStatusChannel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA135120 ksym/sec37800000 Hz48.0 dBmV
2LockedATDMA165120 ksym/sec17400000 Hz47.0 dBmV
3LockedATDMA155120 ksym/sec24200000 Hz47.3 dBmV
4LockedATDMA145120 ksym/sec31000000 Hz47.5 dBmV
 
Last edited:
That is interesting for the tech to say.

Is this modem on the list of supported devices for your plan or does it actually say you need docsis 3.1. Many cables systems can actually run a mix of docsis 3 and 3.1 with the faster plans using the extra channels without impacting the 3.0

Most times what sync errors mean is the ISP equipment is having some issue. Now maybe the ISP equipment got damaged and it no longer works on docsis 3.0 .

This is hard to say because the customer service you call is going to be even more clueless than the low level techs they send out to troubleshoot things. You normally have to get a more senior field tech to fix hard issues that are not fixed by replacing cables and ends.
 
Mar 30, 2022
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That I can see, Suddenlink does not offically post a supported list of modems. There are some lists on the web showing it's supported & others show it's not.

No packets dropping today. I'm curious if the device the tech hooked up to my cable line yesterday and ran tests with, fixed something..? Maybe after everything in the area came back online for a few days things have 'leveled' out?
 
Clear the log if you can or try to see if you are getting new sync errors. You really should see almost no errors messages.

From what I know sync errors are almost always something with the ISP equipment. The timing between the ISP equipment and the end modems are what allows multiple modems in people houses to coexist without transmitting over the top of each other. In theory I guess it could be a defective modem but when it affects multiple people then it more likely some defect in the ISP equipment.

Unfortunately only the ISP equipment has good diagnostics, you are almost lucky that the modem even gives a error message.
 
Mar 30, 2022
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Thanks Bill. It seemed to level out somewhere around the Mar 31 / Apri 1. Since the last log file seen in my inital post, below logs have occured. With the exception of time having passed... to my knowledge - nothing has changed with my network environment; same hardware / wiring / firmware / devices throughout.

TimePriorityDescription
Wed Apr 06 22:41:44 2022Error (4)DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VE...
Tue Apr 05 08:47:00 2022Warning (5)TEK Invalid - Invalid Key Sequence Number;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
Mon Apr 04 02:43:10 2022Error (4)DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VE...
Thu Mar 31 10:34:36 2022Warning (5)MDD message timeout;CM-MAC=98🇩🇪d0:86:74:b8;CMTS-MAC=00:01:5c:b8:80:79;CM-QOS=1.1;CM-VER=3.0;
 

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