R7800 loses connection to SB modem when streaming

[CS0]

Hi, this just started happening, so I’m not sure it’s related to a firmware upgrade. Rebooting the router seems to fix it temporarily, but the status page will show the link gets lost to the modem and the gui says the modem is unplugged. As best I can tell it’s triggered by downloading or streaming, when idle or there’s low traffic it stays up. It’s possible it’s an issue with the modem too, but rebooting the modem does not temporarily fix the problem while rebooting the router does, so seems like the router is at fault.

This is Firmware v1.0.2.90

Anyone have any ideas?

[FURRYe38]

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

Does the Internet LED on the router turn AMBER when this happens? 

Are you wired or wireless when streaming? 

What devices are you usinng? 

Has a power off for 1 minute then back ON with the ISP modem and router been performed since last update?
Be sure to restart your network in this sequence:
Turn off and unplug modem.
Turn off router and computers.
Plug in and turn on modem. Wait 2 minutes for it to connect.
Turn on the router and wait 2 minutes for

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem and router for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

[CS0]

It’s a Motorola SB6141. Comcast. Lights on modem stay blue/geeen, no amber. Wireless, but I can connect to the router to get its status so it’s not a Wi-Fi issue. Seems to just be the link state between the modem and the router.

[Kitsap]

Did you go through the start-up sequence like was recommended?

Make sure your Ethernet cable between your modem and the router is good.

When you last updated your firmware, did you do a firmware default reset and reconfigure the router or did you do a dirty update and leave the configuration from the previous firmware in place?

[CS0]

The cable appears fine. I’m not sure cables fail like this. It seems like something else is going on.

[CS0]

The router is set to auto update it’s firmware.

[FURRYe38]

So the Internet LED on the R7800 remains blinking WHITE when this happens?

Has a power off for 1 minute then back ON with the ISP modem and router been performed since last update?
Be sure to restart your network in this sequence:
Turn off and unplug modem.
Turn off router and computers.
Plug in and turn on modem. Wait 2 minutes for it to connect.
Turn on the router and wait 2 minutes for

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem and router for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

Be sure your using good quality LAN cable between the modem and router. CAT6 is recommended. 

Try a full factory reset and setup from scratch on the router. Don't enable any parental controls, Armor or Traffic meter. 

[CS0]

The modem looks ok when I check it yeah. But I'm also wondering if Comcast is sending reboots to the modem on Sunday nights which causes the router to see the modem go offline. There could be multiple things going on I wonder. As that today things seem fine again.

I found logs of my modem giving up on Comcast and rebooting... so I'm wondering if it's Comcast doing dumb stuff now.

Mar 21 2022 08:24:09	3-Critical	R02.0	No Ranging Response received - T3 time-out;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:90:f0:1d:06:00;CM-QOS=1.1;CM-VER=3.0;
Mar 20 2022 23:12:22	5-Warning	Z00.0	MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:90:f0:1d:06:00;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:17	6-Notice	N/A	Cable Modem Reboot due to T4 timeout ;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 20 2022 23:11:31	3-Critical	R02.0	No Ranging Response received - T3 time-out;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:90:f0:1d:06:00;CM-QOS=1.1;CM-VER=3.0;
Mar 20 2022 23:11:31	3-Critical	R07.0	Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:90:f0:1d:06:00;CM-QOS=1.1;CM-VER=3.0;
Mar 20 2022 23:11:21	6-Notice	I502.0	Received REG-RSP while in REG-HOLD1 state;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:90:f0:1d:06:00;CM-QOS=1.1;CM-VER=3.0;
Mar 20 2022 23:10:18	5-Warning	Z00.0	MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:90:f0:1d:06:00;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:18	6-Notice	N/A	Cable Modem Reboot due to T4 timeout ;CM-MAC=cc:65:ad:d3:4c:73;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

[FURRYe38]

Ya events are seeing criticals that the ISP needs to resolve. 

https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/

Also have them check the signal and power on the line as well. This is for NG modems and not sure if this applies to non NG modems:

https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router?article=24311

[CS0]

Oh yeah the T4 event is listed in the link there, so it's likely Comcast causing the modem to reboot, the router then thinks the modem went offline, I go over to the modem and look at the lights and by that time it's back up and everything is green. This seems likely to me. 

[FURRYe38]

👍