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Constant Network Drops

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Constant Network Drops

I've tried everything on my end repeatedly for weeks to resolve this issue, which seems to only be compounded by dense tier 1 support. 

 

There are no splitters. Physical PC connection to the modem to the wall cable. Constant disconnections as though im being throttled or unplugged. 

 

Fri Jun 26 14:54:04 2020 Notice (6) TLV-11 - unrecognized OID;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Notice (6) WiFi Interface [wl0] set to Channel 36 (Side-Band Channel:N/A) - Reason:INIT
Fri Jun 26 14:52:41 2020 Critical (3) Resetting the cable modem due to docsDevResetNow
Thu Jun 25 07:16:03 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 07:15:06 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 07:13:43 2020 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 07:11:08 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 07:08:13 2020 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 06:33:32 2020 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 06:33:28 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 06:33:10 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 06:32:34 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 06:32:07 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Thu Jun 25 06:31:15 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 23 10:41:24 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 23 10:41:13 2020 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Tue Jun 23 10:41:02 2020 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
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Expert

Re: Constant Network Drops

Please also post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?




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Re: Constant Network Drops

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 8 429000000 Hz -1.5 dBmV 39.8 dB 105 43
2 Locked QAM256 9 435000000 Hz -1.4 dBmV 39.9 dB 0 0
3 Locked QAM256 10 441000000 Hz -1.4 dBmV 39.0 dB 0 0
4 Locked QAM256 11 453000000 Hz -1.1 dBmV 39.5 dB 0 0
5 Locked QAM256 12 459000000 Hz -1.1 dBmV 39.9 dB 0 0
6 Locked QAM256 13 465000000 Hz -0.8 dBmV 40.3 dB 102 25
7 Locked QAM256 14 471000000 Hz -0.7 dBmV 40.1 dB 0 0
8 Locked QAM256 15 477000000 Hz -0.6 dBmV 40.2 dB 0 0
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 27 5120 Ksym/sec 23700000 Hz 44.0 dBmV
2 Locked ATDMA 25 5120 Ksym/sec 36500000 Hz 45.0 dBmV
3 Locked ATDMA 26 5120 Ksym/sec 30100000 Hz 44.5 dBmV
4 Locked ATDMA 28 5120 Ksym/sec 17300000 Hz 43.0 dBmV

 

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Re: Constant Network Drops

The Xfinity Tech was out here today. My DownStream SNR was down to 32 (again, thanks Xfinity's customer service reps that kept telling me nothing was wrong for the last 3-6 weeks). There was apparently some water damage to the lines in the box on the house, a new ground needed, and the local box had something replaced too. 

 

As you can see, the SNR is hitting the ideal 40 now, however despite this, I am still getting disconnects (5'ish since the Comcast Xfinity Rep left 2 hours ago).

 

The new event log shows a full page (which caps at 60 I think) of SYNC Timing failures, below.

Sun Jun 28 08:43:41 2020 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 28 08:43:11 2020 Warning (5) MDD message timeout;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 28 08:43:10 2020 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Sun Jun 28 08:40:52 2020 Notice (6) TLV-11 - unrecognized OID;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:01:5c:65:38:64;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=30:60:23:74:a9:b8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

 

 

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Re: Constant Network Drops

C:\WINDOWS\system32>ping -t -l 900 bbc.co.uk

Pinging bbc.co.uk [2a04:4e42:600::81] with 900 bytes of data:
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=9ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=12ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=13ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=10ms
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Reply from 2a04:4e42:600::81: time=21ms
Reply from 2a04:4e42:600::81: time=14ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=12ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=12ms
Reply from 2a04:4e42:600::81: time=10ms
Reply from 2a04:4e42:600::81: time=12ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=12ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=11ms
Reply from 2a04:4e42:600::81: time=12ms
Reply from 2a04:4e42:600::81: time=11ms
Request timed out.
Request timed out.
Request timed out.
Request timed out.

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New Poster

Re: Constant Network Drops

A visual representation of my internet by ping... constant on/off. Net good, Net bad (those 900bytes were more often timed out then successful).

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Expert

Re: Constant Network Drops

900 bytes. That's a lot of network stress ! What do the standard 32-byte ping probes look like ?



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Re: Constant Network Drops

The 900 bytes SHOULD be irrelevant in this context, the take away should be that the ping succeeds for several seconds, the loses connection/response for several minutes, then regains connection, then loses it. 

 

My 100+ Mbps down rate and 5mbps up rate (Xfinity Performance Select, internet only) should NOT care enough about 0.9 kilobytes rate to warrant complete disconnects or prompt intermitent connectivity.

 

https://xfinityorg.speedtestcustom.com/result/be708280-b978-11ea-a46e-e1f1aa3cc433

 

That being said, the 32byte test was the same, with slightly more successful replies before timing out again for periods of time. 

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Expert

Re: Constant Network Drops

No. It's not irrelevant. Quite the contrary. ICMP packet based probes are already de-prioritized / rate limited by network routers and servers in the first place. If you bombard then even more, then even more will not be returned.

 

This is not to say that you are not having some kind of connectivity problem. Start here;


https://forums.xfinity.com/t5/Your-Home-Network/Internet-Troubleshooting-Tips/m-p/3310447#M316652



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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.
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