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Unexpected reboot reported on IOS-XE router after cellular interface flaps. Before the reboot is can be seen a scheduler watchdog error logs: %IOSXE-2-PLATFORM: R0/0: kernel: cwan_eth0: Tx ERROR RETURN urb: XXXXXXXXXXXX status: -ESHUTDOWN IOSXE-WATCHDOG: Process = DBAL EVENTS %SCHED-0-WATCHDOG: Scheduler running for a long time, more than the maximum configured (26) secs. -Traceback= As consequence of the reboot it is generated a system report with crashinfo file and IOSd core inside.
It was reported on C8200 cEdge router but it can happen with any other IOS-XE platform with cellular interface flaps. Bad cell service or poor installed antenas on the LTE model can trigger the reboot.
If reboots are constant or causing impact on services consider to turn of temporarely the cellular interface. As workaround there is a way to avoid the cellular internface to reset itself and trigger the IOS level crash. 1. Disable automatic reloading of modems. The config has been done in all the cellular controller interface: controller Cellular 0/2/0 lte modem link-recovery disable 2. Configure an EEM script to manually reset the interfaces: event manager applet CELLULAR-1 authorization bypass event timer watchdog time 60 maxrun 30 action 01.00 cli command "enable" ! action 01.10 syslog msg "\n--- Checking to see if Cellular Modem 1 has an IP address ---" action 02.10 cli command "show ip interface brief | inc Cellular0/2" action 02.20 regexp ".[0-9]+.[0-9]+.[0-9]+.[0-9]+" "$_cli_result" action 02.30 if $_regexp_result eq "0" action 03.00 syslog msg "\n--- Cellular Modem 1 does not have IP address. Resetting interfaces. ---" action 03.10 cli command "clear interface Cellular0/2/0" action 03.20 cli command "clear interface Cellular0/2/1" action 04.00 end If multiple cellular interfaces are in used consider to configure as many EEMs as necessary. The previous EEM is for cellular interfaces in card cellular0/2. Here is a configuration change for ceullar0/3 interfaces: event manager applet CELLULAR-2 authorization bypass event timer watchdog time 60 maxrun 30 action 01.00 cli command "enable" ! action 01.10 syslog msg "\n--- Checking to see if Cellular Modem 2 has an IP address ---" action 02.10 cli command "show ip interface brief | inc Cellular0/3" action 02.20 regexp ".[0-9]+.[0-9]+.[0-9]+.[0-9]+" "$_cli_result" action 02.30 if $_regexp_result eq "0" action 03.00 syslog msg "\n--- Cellular Modem 2 does not have IP address. Resetting interfaces. ---" action 03.10 cli command "clear interface Cellular0/3/0" action 03.20 cli command "clear interface Cellular0/3/1" action 04.00 end Consider the changes in the EEM name and action commands. The use of the workaround can reboot the device on booting, however once booted it remains stable. Consider to avoid the workaround if possible and migrate to a fixed code.
If suspecting the issue might impact a device consider to collect admin tech + cores if the device is running in controller mode. Or collect show tech + system reports if the device is running autonomous mode. With the files open a TAC case for confirmation and further steps. Fix is implemented on 17.12.5 and higher code. Check known fix releases section to check the complete fix codes list.
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