RT86U intermittent (almost daily) disconnections, ethernet + wifi

[CivilAnchor]

Hi folks,

I seem to be running into an issue with my newly purchased rt86u. Everything seems to be running great except that I occasionally seem to be runing into a full network disconnection overnight.

Initially I was concerned that it was this 2.4Ghz radio issue that I've heard about, but everything is down including my LAN PC until a router reboot (no modem reboot necessary). I can still access the router page successfully, and all the lights on the router appear to be blinking normally.

Side note: I have the RT86U running in a mesh as the primary with a RC68U. Routers have the latest updated Merlin FW.

This is what I was able to capture in the network log, any ideas? Last happened about 3-4 hours ago, so probably June 19th 6am. Log file is attached.

Thanks!

 

[ColinTaylor]

There doesn't seem to be much information in your log file. Have you turned the log level down, or maybe the default has changed? For example, I can't see any of the usual boot up, DHCP or WAN entries.

 

[CivilAnchor]

Yeah, I had it set to log more than warning so I could see errors easier. Should I change it back to notice or info?

 

[ColinTaylor]

I would change it back to info and higher (i.e. debug), which is the default IIRC.

 

[CivilAnchor]

Thanks, changed it back to debug and managed to capture it happening again.

Seems tt happen around 5:50 based on when i got notifications of stuff going offline, but could have happened earlier than that.

 

[ColinTaylor]

There's nothing in the log to indicate any problems have occurred. Devices seem to be connecting normally. What were the symptoms?

 

[CivilAnchor]

Just all my devices, both wired and wireless lose internet.

Wired connections cannot connect to the internet until I reboot my router. I can access the router's page still.
Wireless connections I'm not sure can even access the router, but I'll have to check when it happens again.

I do not need to reboot my modem to recover, just reboot the router

 

[ColinTaylor]

Have you looked in the modem's logs? What does it say?

 

[CivilAnchor]

Nothing I can tell?


13 06/22/20 07:36:45 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
14 06/22/20 09:51:50 84000500 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
15 06/22/20 09:51:55 84020200 warning Lost MDD Timeout;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
16 06/22/20 09:52:15 82000400 critical Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
17 06/22/20 09:54:38 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
18 06/22/20 09:54:55 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
19 06/22/20 09:55:00 82000500 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;

 

[jata]

I would check if there is an issue with the router picking up a DHCP lease from the modem/ISP - there is a thread related to this issue. See below...

you might also see a message like this in the log - "WAN_Connection: ISP's DHCP did not function properly"

https://www.snbforums.com/threads/a...or-isps-dhcp-did-not-function-properly.61907/

 

[ColinTaylor]

Nothing I can tell?

It would be useful to see a larger log file to get a better understanding of what are "normal" messages. In my own cable modem's case the "SYNC Timing Synchronization failure" messages would usually indicate a fault on the ISP's side.

Have you tried contacting your ISP and asking them to check your connection?

 

[asmopul]

Have you tried contacting your ISP and asking them to check your connection?[/QUOTE]

Or reset the cable modem, for starter.
Does it have a web interface?

 

[CivilAnchor]

Have you tried contacting your ISP and asking them to check your connection?​

Yeah i can try contacting them on the loss of sync message, but would we expect this issue to be a modem issue if rebooting the router solves the issue? Shouldn't the router be able to handle that sort of failure?

Or reset the cable modem, for starter.
Does it have a web interface?
​

Yeah it has a web interface, that's how I gathered those logs. Anything else I should be looking for in particular?

 

[ColinTaylor]

Yeah i can try contacting them on the loss of sync message, but would we expect this issue to be a modem issue if rebooting the router solves the issue? Shouldn't the router be able to handle that sort of failure?

It might not be a modem issue but something further upstream like a DHCP or provisioning server. The point being that there is nothing in the router's log to indicate any kind a problem has occurred.

It could be a DHCP issue but then I'd expect to see the message mentioned in post #10, but we're not. Have a look at Network Map > Internet status > Lease Time and Lease expires. Is the lease particularly short (e.g. < 24 hours)?

Yeah it has a web interface, that's how I gathered those logs. Anything else I should be looking for in particular?

Try to get more log entries. Only having 7 entries to look at doesn't reveal much.

 

[CivilAnchor]

It might not be a modem issue but something further upstream like a DHCP or provisioning server. The point being that there is nothing in the router's log to indicate any kind a problem has occurred.

It could be a DHCP issue but then I'd expect to see the message mentioned in post #10, but we're not. Have a look at Network Map > Internet status > Lease Time and Lease expires. Is the lease particularly short (e.g. < 24 hours)?

Lease time looks to be 2 days. If it's an upstream provisioning issue though, would resetting the router solve the problem without touching the modem?

Try to get more log entries. Only having 7 entries to look at doesn't reveal much.

Yeah, this is all that's in the logs unfortunately. I can wait longer to see if I capture something again, perhaps the SYNC message shows up again and matches with failures? I'm not sure why the logs cut off 5 days ago unless there's a small amount of space in the ringbuffer for that.

No. Time Type Priority Event
1 06/18/20 14:17:49 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
2 06/18/20 14:48:45 84020200 warning Lost MDD Timeout;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
3 06/19/20 09:27:24 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
4 06/19/20 11:06:28 84020200 warning Lost MDD Timeout;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
5 06/19/20 11:06:28 84000500 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
6 06/19/20 11:06:34 84020200 warning Lost MDD Timeout;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
7 06/19/20 11:06:57 82000400 critical Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
8 06/19/20 11:10:41 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
9 06/19/20 11:11:01 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
10 06/22/20 08:36:45 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
11 06/22/20 10:51:50 84000500 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
12 06/22/20 10:51:55 84020200 warning Lost MDD Timeout;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
13 06/22/20 10:52:15 82000400 critical Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
14 06/22/20 10:54:38 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
15 06/22/20 10:54:55 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
16 06/22/20 10:55:00 82000500 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
17 06/23/20 02:32:14 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
18 06/23/20 04:16:40 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
19 06/23/20 18:08:00 82000200 critical No Ranging Response received - T3 time-out;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;
20 06/23/20 21:12:31 90000000 warning MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=aa:bb:cc:dd:92:d0;CMTS-MAC=aa:bb:cc:dd:c1:b0;CM-QOS=1.1;CM-VER=3.0;

 

[ColinTaylor]

My modem has the same 20 line log buffer.

I would be concerned about the number/frequency of critical errors in the log. The occasional (e.g. once or twice a week) "T3 time-out" is acceptable, but you're getting multiple errors a day.

I'm particularly suspicious of the fact that the two blocks of SYNC related errors were almost exactly 24 hours apart (unless that was you resetting the modem?). Also bear in mind that the timestamp might not match your local time. My modem's log always shows GMT times for example.

Of course as you say, even if there is a problem with your internet feed the router should continue to work once the ISP fault has cleared. But stranger things have happened....

Regardless, it's worth reporting the errors to your ISP.