I'm in a similar situation. I tried posting this as a new post but it got flagged as spam for some reason...
Since moving into our new house in June 2018, we continue to lose internet connection regularly. It happens usually once a day, but sometimes multiple times a day. Each time it is accompanied by the dreaded "SYNC Timing Synchronization failure" error (current modem event log copied below, along with current connection details). Our first modem was the Netgear CM1000. After troubleshooting online and over the phone with Cox and being told everything looked fine on their end, we got a Cox technician to come out and check the lines. After some minor fixes to the filters and wiring for our house by the technician, the problem still continued. I thought it might be that the modem was bad, so I switched to the Arris SB8200, which is our current modem. The problem has continued with the new modem. Any help would be appreciated to resolve this.
The table below contains the log of events that the SB8200 has detected. This log can be important to the service provider to help diagnose and correct problems, if any should occur.
| Time | Priority | Description |
|---|---|---|
| 11-2-2018, 21:30:19 | Critical(3) | "Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 11-2-2018, 18:25:33 | Warning(5) | "Dynamic Range Window violation" |
| 11-2-2018, 18:25:33 | Warning(5) | "RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 11-2-2018, 18:25:28 | Notice(6) | "DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 .;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 11-2-2018, 18:25:21 | Notice(6) | "TLV-11 - unrecognized OID;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:30 | Warning(5) | "DHCP WARNING - Non-critical field invalid in response ;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:28 | Notice(6) | "Honoring MDD; IP provisioning mode = IPv4" |
| 1-1-1970, 0:0:18 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:27 | Critical(3) | "No Ranging Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:18 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 11-2-2018, 18:16:16 | Critical(3) | "Resetting the cable modem due to docsDevResetNow" |
| 1-1-1970, 0:0:35 | Critical(3) | "No Ranging Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:18 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 10-31-2018, 15:27:46 | Critical(3) | "Resetting the cable modem due to docsDevResetNow" |
| 1-1-1970, 0:0:18 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 10-30-2018, 17:51:44 | Critical(3) | "Resetting the cable modem due to docsDevResetNow" |
| 1-1-1970, 0:0:18 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 10-23-2018, 14:6:8 | Critical(3) | "Resetting the cable modem due to docsDevResetNow" |
| 1-1-1970, 0:2:4 | Critical(3) | "No Ranging Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:2:1 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:1:53 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:28 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 1-1-1970, 0:0:56 | Critical(3) | "Telnet user logged in from IP address 192.168.100.101." |
| 1-1-1970, 0:0:28 | Critical(3) | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
The status listed show the connection state of the cable modem. They are used by your service provider to evaluate the operation of the cable modem.
| Startup Procedure | ||
|---|---|---|
| Procedure | Status | Comment |
| Acquire Downstream Channel | 957000000 Hz | Locked |
| Connectivity State | OK | Operational |
| Boot State | OK | Operational |
| Configuration File | OK | |
| Security | Enabled | BPI+ |
| DOCSIS Network Access Enabled | Allowed | |
| Downstream Bonded Channels | ||||||||
|---|---|---|---|---|---|---|---|---|
| Channel ID | Lock Status | Modulation | Frequency | Power | SNR/MER | Corrected | Uncorrectables | |
| 30 | Locked | QAM256 | 957000000 Hz | 0.2 dBmV | 34.7 dB | 462 | 0 | |
| 1 | Locked | QAM256 | 783000000 Hz | 5.9 dBmV | 38.3 dB | 833 | 504 | |
| 2 | Locked | QAM256 | 789000000 Hz | 6.3 dBmV | 38.6 dB | 369 | 0 | |
| 3 | Locked | QAM256 | 795000000 Hz | 6.4 dBmV | 38.6 dB | 231 | 0 | |
| 4 | Locked | QAM256 | 801000000 Hz | 6.9 dBmV | 39.0 dB | 180 | 0 | |
| 9 | Locked | QAM256 | 831000000 Hz | 5.7 dBmV | 38.1 dB | 7303 | 4762 | |
| 10 | Locked | QAM256 | 837000000 Hz | 4.7 dBmV | 37.8 dB | 518 | 0 | |
| 11 | Locked | QAM256 | 843000000 Hz | 5.2 dBmV | 37.8 dB | 828 | 0 | |
| 12 | Locked | QAM256 | 849000000 Hz | 3.9 dBmV | 37.2 dB | 1195 | 0 | |
| 17 | Locked | QAM256 | 879000000 Hz | 4.6 dBmV | 37.7 dB | 758 | 0 | |
| 18 | Locked | QAM256 | 885000000 Hz | 3.5 dBmV | 37.1 dB | 902 | 0 | |
| 19 | Locked | QAM256 | 891000000 Hz | 3.9 dBmV | 37.3 dB | 928 | 0 | |
| 20 | Locked | QAM256 | 897000000 Hz | 3.0 dBmV | 36.8 dB | 977 | 0 | |
| 21 | Locked | QAM256 | 903000000 Hz | 3.0 dBmV | 36.8 dB | 873 | 0 | |
| 22 | Locked | QAM256 | 909000000 Hz | 1.9 dBmV | 35.8 dB | 1995 | 0 | |
| 25 | Locked | QAM256 | 927000000 Hz | 1.5 dBmV | 35.6 dB | 681 | 0 | |
| 26 | Locked | QAM256 | 933000000 Hz | 1.6 dBmV | 35.7 dB | 1045 | 0 | |
| 27 | Locked | QAM256 | 939000000 Hz | 0.3 dBmV | 34.7 dB | 930 | 0 | |
| 28 | Locked | QAM256 | 945000000 Hz | 1.1 dBmV | 35.4 dB | 660 | 0 | |
| 29 | Locked | QAM256 | 951000000 Hz | -0.3 dBmV | 34.4 dB | 652 | 0 | |
| 33 | Locked | QAM256 | 357000000 Hz | 8.8 dBmV | 40.3 dB | 0 | 0 | |
| 34 | Locked | QAM256 | 363000000 Hz | 9.0 dBmV | 40.4 dB | 0 | 0 | |
| 35 | Locked | QAM256 | 369000000 Hz | 9.5 dBmV | 40.7 dB | 0 | 0 | |
| 36 | Locked | QAM256 | 375000000 Hz | 9.6 dBmV | 40.7 dB | 0 | 0 | |
| 37 | Locked | QAM256 | 381000000 Hz | 9.9 dBmV | 40.8 dB | 0 | 0 | |
| 38 | Locked | QAM256 | 387000000 Hz | 10.2 dBmV | 40.8 dB | 0 | 0 | |
| 41 | Locked | QAM256 | 405000000 Hz | 10.5 dBmV | 40.9 dB | 0 | 0 | |
| 42 | Locked | QAM256 | 411000000 Hz | 10.8 dBmV | 41.1 dB | 0 | 0 | |
| 43 | Locked | QAM256 | 417000000 Hz | 10.6 dBmV | 41.1 dB | 0 | 0 | |
| 44 | Locked | QAM256 | 423000000 Hz | 10.8 dBmV | 41.1 dB | 0 | 0 | |
| 45 | Locked | QAM256 | 429000000 Hz | 10.5 dBmV | 40.9 dB | 0 | 0 | |
| 46 | Locked | QAM256 | 435000000 Hz | 11.0 dBmV | 41.2 dB | 0 | 0 | |
| 159 | Locked | Other | 300000000 Hz | 12.4 dBmV | 41.2 dB | 23165813 | 0 | |
| Upstream Bonded Channels | ||||||
|---|---|---|---|---|---|---|
| Channel | Channel ID | Lock Status | US Channel Type | Frequency | Width | Power |
| 1 | 1 | Locked | SC-QAM | 16900000 Hz | 6400000 Hz | 43.0 dBmV |
| 2 | 2 | Locked | SC-QAM | 23500000 Hz | 6400000 Hz | 43.0 dBmV |
| 3 | 3 | Locked | SC-QAM | 29900000 Hz | 6400000 Hz | 44.0 dBmV |
| 4 | 4 | Locked | SC-QAM | 36300000 Hz | 6400000 Hz | 44.0 dBmV |
Current System Time: Sun Nov 4 08:40:20 2018
