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C3000 Wifi Drop-off Issue
TL;DR: The wifi drops off completely and doesn't link back to the Internet at least once a day, no power issues, no connectivity issues. I have the C3000 DOCSIS 3.0 cable gateway on Comcast Xfinity, I'm not using a cable splitter or any other kind of product, my regular wifi download speed exceeds 15Mbps (occassionally goes up to 25Mbps). My wired connectivity hardly drops, but my wifi function has been malfunctioning at least once a day. A powercycle is the only way to fix this issue, and all my settings are under factory default setting, no modifications were done on the modem. Here's what I did to triage the issue: 1. Changing channels after reboot - doesn't work, every channel drops off once in a while 2. Checked power issue, please see following chart for power levels: Downstream Bonded Channels Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables 1 Locked QAM256 13 609000000 Hz -2.1 dBmV 41.9 dB 0 0 2 Locked QAM256 11 597000000 Hz -2 dBmV 41.9 dB 0 0 3 Locked QAM256 12 603000000 Hz -2 dBmV 41.3 dB 0 0 4 Locked QAM256 14 615000000 Hz -2.3 dBmV 41.4 dB 0 0 5 Locked QAM256 15 621000000 Hz -2.2 dBmV 41.3 dB 0 0 6 Locked QAM256 16 627000000 Hz -2.4 dBmV 41.4 dB 0 0 7 Locked QAM256 19 645000000 Hz -1.8 dBmV 41.4 dB 0 0 8 Locked QAM256 20 651000000 Hz -1.8 dBmV 41.4 dB 0 0 Upstream Bonded Channels Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 73 5120 Ksym/sec 17300000 Hz 43.8 dBmV 2 Locked ATDMA 74 5120 Ksym/sec 23700000 Hz 44 dBmV 3 Locked ATDMA 75 5120 Ksym/sec 30300000 Hz 44.8 dBmV 4 Locked ATDMA 76 5120 Ksym/sec 36700000 Hz 44.5 dBmV 3. Checked logs: [Internet connected] IP address: 50.161.98.113 1 Sun Jul 24 09:27:57 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.12] to MAC address a0:99:9b:1e:3b:7b 1 Sun Jul 24 09:27:48 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Sun Jul 24 09:27:47 2016 0.0.0.0:0 0.0.0.0:0 [Time synchronized with ToD server] 1 Sun Jul 24 09:27:43 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.12] to MAC address a0:99:9b:1e:3b:7b 1 Thu Jan 01 00:00:53 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Thu Jan 01 00:00:52 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.12] to MAC address a0:99:9b:1e:3b:7b 1 Thu Jan 01 00:00:42 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Thu Jan 01 00:00:40 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.10] to MAC address 00:18:4d:ff:ff:07 1 Thu Jan 01 00:00:32 1970 0.0.0.0:0 0.0.0.0:0 [Initialized, firmware version: V2.02.08] 1 Thu Jan 01 00:00:31 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.11] to MAC address c0:ee:fb:33:c9:fc 1 Sat Jul 23 18:15:06 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Sat Jul 23 18:15:03 2016 0.0.0.0:0 0.0.0.0:0 [Internet connected] IP address: 50.161.98.113 1 Sat Jul 23 18:15:02 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.14] to MAC address 6c:ad:f8:7f:49:bf 1 Sat Jul 23 18:15:00 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Sat Jul 23 18:14:52 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.14] to MAC address 6c:ad:f8:7f:49:bf 1 Sat Jul 23 18:14:49 2016 0.0.0.0:0 0.0.0.0:0 [Time synchronized with ToD server] 1 Sat Jul 23 18:14:46 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Thu Jan 01 00:00:53 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.11] to MAC address c0:ee:fb:33:c9:fc 1 Thu Jan 01 00:00:47 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Thu Jan 01 00:00:41 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.10] to MAC address 00:18:4d:ff:ff:07 1 Thu Jan 01 00:00:32 1970 0.0.0.0:0 0.0.0.0:0 [Initialized, firmware version: V2.02.08] 1 Thu Jan 01 00:00:30 1970 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.12] to MAC address a0:99:9b:1e:3b:7b 1 Fri Jul 22 21:02:16 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.11] to MAC address c0:ee:fb:33:c9:fc 1 Fri Jul 22 21:02:03 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Fri Jul 22 21:01:59 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.14] to MAC address 6c:ad:f8:7f:49:bf 1 Fri Jul 22 21:01:49 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Fri Jul 22 21:01:48 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.20] to MAC address 38:71:de:db:04:65 1 Fri Jul 22 21:01:41 2016 0.0.0.0:0 0.0.0.0:0 [Internet connected] IP address: 50.161.98.113 1 Fri Jul 22 21:01:40 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.14] to MAC address 6c:ad:f8:7f:49:bf 1 Fri Jul 22 21:01:38 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.16] to MAC address 60:5b:b4:0a:43:b5 1 Fri Jul 22 21:01:37 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.11] to MAC address c0:ee:fb:33:c9:fc 1 Fri Jul 22 21:01:32 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.20] to MAC address 38:71:de:db:04:65 1 Fri Jul 22 21:01:30 2016 0.0.0.0:0 0.0.0.0:0 [DHCP IP: 192.168.0.14] to MAC address 6c:ad:f8:7f:49:bf 1 Fri Jul 22 21:01:27 2016 0.0.0.0:0 0.0.0.0:0 [Time synchronized with ToD server] 1 Fri Jul 22 21:01:26 2016 0.0.0.0:0 0.0.0.0:0 I've marked the time synchronize event to red because these are the exact time that my wifi function stopped working. I think this somehow indicates that either the initialization (causing the system time to revert back to 1970) or the synchronizing event are the root cause of drop offs. 4. Last, you can see from the event log that it indicates a time sychronization failure, timestamp is always at 1970 since the modem was initialized back to 1970: 1970-1-1, 00:00:31 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; 1970-1-1, 00:00:38 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:01:5c:62:1c:58;CM-QOS=1.0;CM-VER=3.0; 1970-1-1, 00:00:32 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; 1970-1-1, 00:00:39 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:01:5c:62:1c:58;CM-QOS=1.0;CM-VER=3.0; 1970-1-1, 00:00:31 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; 1970-1-1, 00:00:38 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:01:5c:62:1c:58;CM-QOS=1.0;CM-VER=3.0; 1970-1-1, 00:00:31 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:30:33:ba:b2:a8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; In all, I think this is a quality issue. I purchased this modem through Amazon in March, and this issue has been very persistent throughout my usage. I have ruled out Xfinity issues and my connected device issues. I hope Netgear can come up with some kind of a fix to this as this is proven to be a problem for many consumers.