One of our customers provided their own SIM card for our nRF9160 based product, and the system works but they have been having higher than expected power consumption.
We have confirmed that EDRX and PSM are enabled and accepted by the cellular towers.
However, we noticed that the APN info reported from the modem has the same IP address that the cloud server sees from the device, meaning it is NOT going through NAT, which we've never seen before. We're now wondering if somehow our customer got SIM cards which provide a public IP address and no firewall, and the node is having to wake up to receive and ignore all sorts of network scans and pings.
We can ping the IP address and get a response, but we don't know how to prove if the nRF9160 modem is responding or if some other network device is responding.
Does the nRF9160 respond to PINGs received from the cellular network? If so, is there some way to tell if that is happening without a modem trace?
If we had the unit on our bench and could still connect to their (foreign to us) cellular network, we would watch the power consumption over time and see if the modem really was waking up more than expected. But we can't, so we're hoping to find some way to determine this remotely.
