For a project we were using several Cisco IR809 cellular modems. One of which was only going to be used because of its smaller size, not for the cellular function. 3 others would be using cellular though.
When I first discovered LibreNMS and tested it out, the one feature that caught my eye was the discovery and graphing for the cellular radio. I had added in these modems, liked what I saw, and switched our NMS to Libre. At end of October this project shipped, and for a few weeks the cell modems were offline. At end of October the remote sites were brought online.
Now here is my issue. The one IR809 that has no SIM, no cellular configured, reports RSSI through SNMP polling. The other radios that are in fact using cellular do not show up.Either on the device page itself, or in the RSSI tab at top of page. The IOS versions are same, the SNMP config on the radios is same as well. So I am lost on how one router shows RSSI with no radio function, but the ones that do have do not appear. I have double checked configs, and re-ran discovery with no luck. Hoping for some ideas how I could get the RSSI polling to appear again.
Interesting, I did not think to look at the end device side, as they were working. The discovery showed me the problem when running /usr/bin/snmpbulkwalk -v2c -c COMMUNITY -OQUs -m CISCO-WAN-3G-MIB -M /opt/librenms/mibs:/opt/librenms/mibs/cisco udp:HOSTNAME:161 c3gCurrentGsmRssi
Without any configuration changes or IOS changes since shipping, the 3 actual cellular modems give me this; c3gCurrentGsmRssi = No Such Instance currently exists at this OID
Where as the one unit that is actually not using any cellular or wifi radio has; c3gCurrentGsmRssi.13 = -128
I had thought that somehow it was a configuration issue or change in Libre. Thanks for you reply and help murrant
I am not enough familiar with how LibreNMS is structured or works, but I have to assume I would be able to change OIDs and such for a device. Libre I believe is using "c3gCurrentGsmRssi"whereas the current RSSI can be found at c3gCurrentEvDoRssi.13. Is this easily editable or can be changed?
LibreNMS basically is pre-configured for each device. We are working to make that more accessible but sometimes, you just need to edit code to make changes.
Also, it would be correct to add c3gCurrentEvDoRssi support, not replace c3gCurrentGsmRssi. Some users might have GSM modems.
Thank you for you help murrant. I did take a look at Ios.php, but as I have little php knowledge I had no luck adding or even changing temporarily to have the EVDO discovered. So I took your suggestion and submitted at github. I appreciate your help with this.