U

Visitor

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1 Message

Wed, Jul 28, 2021 5:23 AM

Modem is dropping internet connection sporadically

My internet is now dropping several times a day, usually running for only an hour or less before having to be restarted. 

My modem is an Arris SB6183. The event log seems to have an infinite loop of errors being triggered and looks as follows:

Tue Jul 27 17:41:26 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0;
Tue Jul 27 17:41:27 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0;
Tue Jul 27 17:41:32 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0;
Tue Jul 27 17:41:55 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:44:56 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:45:22 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:48:22 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:48:33 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0;
Tue Jul 27 17:48:56 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:51:57 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:52:22 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:55:22 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:55:33 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0;
Tue Jul 27 17:55:56 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:58:56 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 17:59:21 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 18:02:22 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 18:02:33 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0;
Tue Jul 27 18:02:55 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 18:05:56 2021 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
Tue Jul 27 18:06:22 2021 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;

The status specs look like this:

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel   Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK
Security Enabled BPI+
DOCSIS Network Access Enabled Allowed

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 13 495000000 Hz -6.7 dBmV 38.9 dB 0 0
2 Locked QAM256 1 411000000 Hz -7.5 dBmV 39.1 dB 0 0
3 Locked QAM256 2 417000000 Hz -7.7 dBmV 39.0 dB 0 0
4 Locked QAM256 3 423000000 Hz -7.8 dBmV 39.0 dB 0 0
5 Locked QAM256 4 435000000 Hz -7.8 dBmV 39.0 dB 0 0
6 Locked QAM256 5 447000000 Hz -8.0 dBmV 39.0 dB 0 0
7 Locked QAM256 6 453000000 Hz -7.2 dBmV 39.1 dB 0 0
8 Locked QAM256 7 459000000 Hz -7.6 dBmV 38.9 dB 0 0
9 Locked QAM256 8 465000000 Hz -7.0 dBmV 38.9 dB 0 0
10 Locked QAM256 9 471000000 Hz -7.4 dBmV 38.8 dB 0 0
11 Locked QAM256 10 477000000 Hz -6.6 dBmV 39.0 dB 0 0
12 Locked QAM256 11 483000000 Hz -6.7 dBmV 38.9 dB 0 0
13 Locked QAM256 12 489000000 Hz -6.5 dBmV 39.0 dB 0 0
14 Locked QAM256 14 507000000 Hz -6.2 dBmV 37.5 dB 0 0
15 Locked QAM256 15 513000000 Hz -6.5 dBmV 38.8 dB 0 0
16 Locked QAM256 16 519000000 Hz -6.2 dBmV 38.9 dB 0 0

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 10 5120 Ksym/sec 22800000 Hz 49.5 dBmV
2 Locked ATDMA 9 5120 Ksym/sec 16400000 Hz 49.5 dBmV
3 Locked ATDMA 11 5120 Ksym/sec 29200000 Hz 49.5 dBmV
4 Locked ATDMA 12 5120 Ksym/sec 35600000 Hz 50.9 dBmV

Any help would be greatly appreciated!!! Thanks in advance!

Responses

EG

Expert

 • 

89.2K Messages

2 m ago

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

In an 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

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.


Good luck with it !

Official Employee

 • 

221 Messages

2 m ago

Hello @user_f9c50b. Did EG's recommendations help your internet connection? If so, please let us know so the community can benefit from this solution. If not, please let me know what troubleshooting you've done so far to try and resolve this issue.

 

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