Monitoring Cellular Data Usage

I have about 20 cellular routers in the field, each router has a static IP address. The router accepts a SIM card and the carrier is Verizon Wireless. The issue I'm having is that all these devices are using shared/pooled data and they are always exceeding the monthly plan.

I am currently using LibreNMS to monitor the traffic usage over the WAN but my issues are:

• It seems to only be 5 min intervals
• The Verizon Wireless Data Usage does not match what the LibreNMS billing module displays. I'm not sure if this is related to the 5 min interval of SNMP.

I like LibreNMS and I still use it for other devices, but I don't want the solution to be within LibreNMS unless I am doing something very wrong in LibreNMS and it is a simple setting that I've missed.

I want to state that LibreNMS community is great and I have donated to them many times, but most of the time the community recommends editing a bunch of files in LibreNMS and I am not comfortable doing that. I'm looking for a solution that is cloud based or an SNMP type of program that has paid support so that if I do end up going with an SNMP based solution, I can call in if/when I'm having a problem.

I understand that traffic/services are HTTPS based and that additional equipment, certificates, etc may need to be put in place in order for this to work properly. Since there is a business reason for wanting to track data on company owned equipment, I would also consider options that require a middle box/certificates/etc to be installed between the cellular routers and the computer/devices that connect to the cellular routers. At this point I'm simply looking for options from those who have gone through this, before.

The other issue with LibreNMS is that the interface usage doesn't match up with what LibreNMS billing is stating. For example, the billing module shows that one cellular router used 18GB of data in the last billing period (I've properly defined the billing period dates). However, when I check the interface stats for that router, the device barley peaked above 1MB. You can see the 1MB spike and all other graph data indicates that the traffic was much lower than 1MB throughout the billing cycle. Again, this could be due to the 5 min SNMP interval.

I have a call in to my Account Manager to see if they can 'sell' me additional data usage services and I'm also going to ask about upgrading the shared monthly billing package. I'm going this before I go to the higher ups because I'd like to have answers and/or possible solutions when presenting them with the problem.

At the end of the day, it may be cheaper to simply bump up the monthly data usage plan and that may be all that is needed.

Thanks.