Question

On some of our RUTX11 devices wwan0 interface number changes by itself even without restarting the device. We are reading status of devices over SNMP ver2 and wwan0 sensor just stops to response. After investigation i found out that wwan0 interface number is now 40(random number) and was previously 12. After firmware flash the value goes back to default. We are on latest 02.6 firmware RUTX_R_00.02.06.1. same situation with previous version RUTX_R_00.02.05.2

Attching Troubleshoot file  - the interface number changed at 17:36 02.06.2022. 

Answer 1

Hello,

Interfaces must be addressed indirectly there is no guarantee that they are the same across different devices nor that they stay fixed:

1. parse HOST-RESOURCES-MIB::hrNetworkIfIndex : snmpwalk -v 2c -c public ip-of-the-router HOST-RESOURCES-MIB::hrNetworkIfIndex, this will give you the list of interfaces with their index, 
2. for each index from above do a snmpget -v 2c -c public ip-of-the-router IF-MIB::ifName.(the index from 1) you'll have all the existing interfaces names note the one of wwan0. You can then access all the variables you are interested in : IF-MIB::ifMtu.x IF-MIB::ifSpeed.x IF-MIB::ifOperStatus.x and so on.

Regards,