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Another T3 T4 question.

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Regular Visitor

Another T3 T4 question.

Over the past 4 days, have had more frequent outages. Called Xfinity 3 times, and Netgear 4 times. Comcast said things looked good to them, and that they were unable to send a tech out due to pandemic here (understandable--we're bad now). Netgear had me do multiple interventions, and is sending me out a new modem (cm7800 nighthawk), but they aren't sure what's up. My modem has worked fine for 2 months. However, no one is able to tell me if it's the cable signal or the modem. Can you tell from the modem log? I tried to educate myself, but I cannot get an answer ("dirty signal upstream?" vs modem issue). Here is a log of a recent interruption (reverse time order). Thanks for any help...

 

2020-07-05, 14:53:18

Warning (5)

MDD message timeout;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:53:03

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:53:02

Warning (5)

Dynamic Range Window violation

 

2020-07-05, 14:53:02

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

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=bc:a5:11:89:85:7c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:50:24

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:50:24

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:48:34

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:48:14

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:48:02

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:48:00

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:54

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:42

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:39

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:34

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:09

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:07

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:47:00

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:46:58

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

 

2020-07-05, 14:46:22

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=bc:a5:11:89:85:7c;CMTS-MAC=00:9e:1e:59:0b:20;CM-QOS=1.1;CM-VER=3.1;

Highlighted
Expert

Re: Another T3 T4 question.

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




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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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Regular Visitor

Re: Another T3 T4 question.

Thanks for the reply. The Netgear folks had me chack last week. The range was -0.1 to about 1.9. They said that was fine. 

 

However, this AM when it went out, things were different. I checked and saw upstream and downstream were all 0. 

Here was part of the log from the most recent outage (from a screenshot):

 

[admin login] from source 192.168.0.4, Mon, Jul 06, 2020 14:55:12

[Internet disconnected] Mon, Jul 06, 2020 14:53:52

[admin login] from source 192.168.0.4, Mon, Jul 06, 2020 14:53:42

[DHCP IP: (192.168.0.3)] to MAC address 00:18:61:28:cc:ab, Mon, Jul 06, 2020 14:52:55

[DoS attack: Echo char gen] from source: 83.97.20.35, port 58136, Mon, Jul 06, 2020 14:20:56

[DHCP IP: (192.168.0.15)] to MAC address 18:55:e3:77:1f:a7, Mon, Jul 06, 2020 13:51:11

[DHCP IP: (192.168.0.10)] to MAC address 18:55:e3:65:e3:21, Mon, Jul 06, 2020 13:46:17

[DoS attack: Echo char gen] from source: 52.73.169.169, port 51121, Mon, Jul 06, 2020 12:16:32

[DoS attack: Echo char gen] from source: 83.97.20.35, port 57532, Mon, Jul 06, 2020 09:27:41

[DoS attack: UDP Scan] from source: 202.115.254.100, port 59111, Mon, Jul 06, 2020 08:44:25

[DoS attack: Echo char gen] from source: 80.82.77.139, port 29921, Mon, Jul 06, 2020 08:06:33

[DoS attack: Echo char gen] from source: 172.104.7.170, port 40602, Mon, Jul 06, 2020 08:03:32

[DoS attack: UDP Scan] from source: 109.123.117.247, port 19, Mon, Jul 06, 2020 03:44:16

[DoS attack: UDP Scan] from source: 71.6.233.146, port 17, Mon, Jul 06, 2020 03:12:16

[DHCP IP: (192.168.0.18)] to MAC address 74:54:7d:ff:b7:10, Mon, Jul 06, 2020 01:50:41

[DoS attack: Echo char gen] from source: 184.105.139.101, port 49077, Mon, Jul 06, 2020 01:20:17

[DoS attack: Echo char gen] from source: 146.88.240.4, port 56517, Mon, Jul 06, 2020 00:32:55

Highlighted
Regular Visitor

Re: Another T3 T4 question.

 Also, everytime there's an outage, I reboot the modem and it comes back (at least for a while). Does this mean it's the modem/router, or is a bad or dirty data stream/signal from the ISP?

 

Highlighted
Expert

Re: Another T3 T4 question.

Would you please post a screenshot or paste the text of the entire signal status page for us to see. 

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




I am not a Comcast Employee.
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.
Was your question answered? Mark the post as Best Answer!
Highlighted
Regular Visitor

Re: Another T3 T4 question.

It won't let me upload pics...here is the data:

downstream: power range -1.7 to +1.7 dBmV (channel 21-28 is all 0). SNR all 38.3-38.8 dB

 

upstream: power: 34.5-37.3 dBmV (channels 6-8 are not locked, and 0 power)

 

Thanks!