Internet keeps randomly dropping

Start here;

https://forums.xfinity.com/t5/Your-Home-Network/Connection-Troubleshooting-Tips/m-p/1253575#M94474

Post the requested info from here;

https://forums.xfinity.com/t5/Your-Home-Network/Information-Requested-for-Connection-Related-Posts/m-p/1253381#M192739

That sounds like a DHCP IP address lease length issue either with them or your router. You haven't posted any of the requested info...

Hello there,

I have gather these informations:

• Post your modem’s error logs. 
• Post the make and model of your modem/gateway.
• Post the make and model of your router if you have one.
• Let us know if you contacted Comcast or had a tech visit.
• Let us know what the lights on your modem are doing when you are having problems.

1. 

Model: CM-32_AC2600
Firmware Version: 1.0.1.5
PIN Code: 54335561
Gateway Serial Number: JBIABT001341
CM MAC Address: 2C:FD:A1:90:BE:18
Acquire Downstream Channel : 579000 KHz
Connectivity State : OPERATIONAL
Last Operational Time : Sun Oct 13 14:25:12 UTC 2019

2019-10-13 13:53:31 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-13 13:53:31 [CRITICAL] Ranging Request Retries exhausted
2019-10-13 13:53:31 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-13 13:53:31 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 13:57:20 [CRITICAL] Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
2019-10-13 13:58:00 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 13:58:40 [WARNING] MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
2019-10-13 14:18:30 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 14:19:14 [CRITICAL] Ranging Request Retries exhausted
2019-10-13 14:19:14 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-13 14:19:15 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 14:19:50 [CRITICAL] Ranging Request Retries exhausted
2019-10-13 14:19:50 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-13 14:19:51 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 14:20:18 [CRITICAL] Ranging Request Retries exhausted
2019-10-13 14:20:18 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-13 14:20:19 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 14:24:02 [CRITICAL] Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
2019-10-13 14:24:47 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-13 14:25:08 [WARNING] MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1

]

signal1

signal2

2. My modem is ASUS cm-32_ac2600

3. Tech visited twice, first time said I had a TV spliter so he get rid of it,  next time found another TV spliter. but the issue still presisit

4. When issue happens, everything looks fine, 4 lights were on and my modem status said it's connceted. although I got a modem disconnect status in my xfinity app, I can still send reset signal back to my modem and my modem can receive it just fine. in about 15min-30min, internet get restored, and from my past 3 day experience, the drop happened around 2pm pst and 2am pst. like it  was beening scheduled 

for some reason the screenshot didn't work, so I will just post the singal here:

USfreqInfo:
['1', '3', 'Locked', '30300000', '64 QAM', '5120000', 'ATDMA', '38.00 dBmV']
['2', '4', 'Locked', '36700000', '64 QAM', '5120000', 'ATDMA', '36.75 dBmV']
['3', '2', 'Locked', '23700000', '64 QAM', '5120000', 'ATDMA', '38.75 dBmV']
['4', '1', 'Locked', '17300000', '64 QAM', '5120000', 'ATDMA', '39.50 dBmV']
['0', '---', 'Unlocked', '0', '---', '---' , '---', '---']
['0', '---', 'Unlocked', '0', '---', '---' , '---', '---']
['0', '---', 'Unlocked', '0', '---', '---' , '---', '---']
['0', '---', 'Unlocked', '0', '---', '---' , '---', '---']

DSfreqInfo:
['1', '1(Prm)', 'Locked', '579000000', '256 QAM', '5360000', '37.636 dB', '3.80 dBmV']
['2', '2', 'Locked', '477000000', '256 QAM', '5360000', '37.636 dB', '4.80 dBmV']
['3', '3', 'Locked', '483000000', '256 QAM', '5360000', '37.356 dB', '4.90 dBmV']
['4', '4', 'Locked', '489000000', '256 QAM', '5360000', '37.356 dB', '5.00 dBmV']
['5', '5', 'Locked', '495000000', '256 QAM', '5360000', '37.636 dB', '5.00 dBmV']
['6', '6', 'Locked', '507000000', '256 QAM', '5360000', '37.356 dB', '5.00 dBmV']
['7', '7', 'Locked', '513000000', '256 QAM', '5360000', '37.636 dB', '5.00 dBmV']
['8', '8', 'Locked', '519000000', '256 QAM', '5360000', '37.356 dB', '4.50 dBmV']
['9', '9', 'Locked', '525000000', '256 QAM', '5360000', '37.636 dB', '4.70 dBmV']
['10', '10', 'Locked', '531000000', '256 QAM', '5360000', '37.636 dB', '4.60 dBmV']
['11', '11', 'Locked', '537000000', '256 QAM', '5360000', '37.356 dB', '4.20 dBmV']
['12', '12', 'Locked', '543000000', '256 QAM', '5360000', '37.636 dB', '4.40 dBmV']
['13', '13', 'Locked', '549000000', '256 QAM', '5360000', '37.356 dB', '4.40 dBmV']
['14', '14', 'Locked', '555000000', '256 QAM', '5360000', '37.356 dB', '4.30 dBmV']
['15', '15', 'Locked', '561000000', '256 QAM', '5360000', '37.636 dB', '4.10 dBmV']
['16', '16', 'Locked', '567000000', '256 QAM', '5360000', '37.636 dB', '4.30 dBmV']
['17', '17', 'Locked', '573000000', '256 QAM', '5360000', '37.356 dB', '3.90 dBmV']
['18', '18', 'Locked', '585000000', '256 QAM', '5360000', '37.356 dB', '4.00 dBmV']
['19', '19', 'Locked', '591000000', '256 QAM', '5360000', '37.636 dB', '4.20 dBmV']
['20', '20', 'Locked', '597000000', '256 QAM', '5360000', '37.636 dB', '4.20 dBmV']
['21', '21', 'Locked', '603000000', '256 QAM', '5360000', '37.356 dB', '4.40 dBmV']
['22', '22', 'Locked', '609000000', '256 QAM', '5360000', '37.636 dB', '4.50 dBmV']
['23', '23', 'Locked', '615000000', '256 QAM', '5360000', '37.356 dB', '4.30 dBmV']
['24', '24', 'Locked', '621000000', '256 QAM', '5360000', '37.356 dB', '4.60 dBmV']
['25', '25', 'Locked', '627000000', '256 QAM', '5360000', '37.300 dB', '4.80 dBmV']
['26', '26', 'Locked', '633000000', '256 QAM', '5360000', '37.300 dB', '4.30 dBmV']
['27', '27', 'Locked', '639000000', '256 QAM', '5360000', '36.900 dB', '4.60 dBmV']
['28', '28', 'Locked', '645000000', '256 QAM', '5360000', '37.900 dB', '4.90 dBmV']
['29', '29', 'Locked', '651000000', '256 QAM', '5360000', '37.300 dB', '4.70 dBmV']
['30', '30', 'Locked', '681000000', '256 QAM', '5360000', '37.300 dB', '5.70 dBmV']
['31', '31', 'Locked', '687000000', '256 QAM', '5360000', '37.600 dB', '6.30 dBmV']
['32', '32', 'Locked', '693000000', '256 QAM', '5360000', '37.300 dB', '6.10 dBmV']

got the log when it drops today:

Model: CM-32_AC2600
Firmware Version: 1.0.1.5
PIN Code: 54335561
Gateway Serial Number: JBIABT001341
CM MAC Address: 2C:FD:A1:90:BE:18
Acquire Downstream Channel : 579000 KHz
Connectivity State : OPERATIONAL
Last Operational Time : Tue Oct 15 06:52:41 UTC 2019

2019-10-15 01:54:41 [WARNING] MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
2019-10-15 12:19:29 [MAJOR] DCC rejected authentication failure
2019-10-15 12:19:30 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 12:21:09 [CRITICAL] Ranging Request Retries exhausted
2019-10-15 12:21:09 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-15 12:21:24 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 13:51:18 [CRITICAL] Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
2019-10-15 13:52:00 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 06:52:37 [WARNING] MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
2019-10-15 12:19:01 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 12:24:01 [CRITICAL] Ranging Request Retries exhausted
2019-10-15 12:24:01 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-15 12:24:06 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 12:24:23 [CRITICAL] Ranging Request Retries exhausted
2019-10-15 12:24:23 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-15 12:24:23 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 19:10:39 [CRITICAL] Ranging Request Retries exhausted
2019-10-15 19:10:39 [CRITICAL] Unicast Maintenance Ranging attempted - No response - Retries exhausted
2019-10-15 19:10:40 [CRITICAL] No Ranging Response received - T3 time-out
2019-10-15 19:14:32 [CRITICAL] Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out

USfreqInfo:
['1', '3', 'Locked', '30300000', '64 QAM', '5120000', 'ATDMA', '-1.00 dBmV']
['2', '4', 'Locked', '36700000', '64 QAM', '5120000', 'ATDMA', '-1.00 dBmV']
['3', '2', 'Locked', '23700000', '64 QAM', '5120000', 'ATDMA', '-1.00 dBmV']
['4', '1', 'Locked', '17300000', '64 QAM', '5120000', 'ATDMA', '-1.00 dBmV']

downstream was empty

Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is noise ingress into the line(s) somewhere.

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They can check the CMTS (Cable Modem Termination System) for any real time degradation and / or error reports, see your node / cable plant and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

Greetings, domodog! We appreciate you taking the time to reach out to us here on the forums. We hope you are having an amazing day. We apologize to hear of the issues you are running into with the internet. Certainly frustrating having the internet drop out like that. As EG has mentioned we would need to take a deeper look into the signal. Can you please send us a PM with your first and last name so we may further assist you?

To send a private message, please click the name "Comcast_Support" then select "Send a Message" on the right side.

I'm having the same problem - exactly!  It started a couple of weeks ago after years of no problems with the same home network setup.  Internet drops off, WiFi still A-OK and all llights on on the modem.

I thought it might be an eqipment issue, so bought a new modem/router (Arris), still the same problem.  Intenet drops off for 15-20 minutes and then comes back on.  Two different modems and different routers, same problem.  

BTW, no luck getting in touch with a Comcast tech.  Ran all of the available checks from the App and website - no joy!