We're looking at adding an option to our product for Cat-M1 data connectivity. The data plans look interesting, but it's very unclear how the data is actually counted. For example... for these AT&T, Verizon, and T-Mobile plans with 1MB of data, does that include the TCP/IP packet overhead?
We have reasonably low data requirements (8 bytes/minute per sensor, 1-15 sensors per device... plus a 26 byte system data packet every 15 minutes). However, if TCP/IP overhead is included, then our 8 bytes/minute becomes a minimum of 88 bytes... possibly a LOT more if the modem is just barely communicating and gets a large number of retries.
Does anyone know how they meter this stuff?
We could drop down to just a data packet every 30 minutes or so, but we'd very much prefer per-minute data. If it includes TCP/IP overhead, then with one update a minute just the packet overhead itself is going to use a minimum of 3.5MB/month.
If TCP/IP overhead is included... Is there some system or protocol (M2X, MQTT, etc) that would be an alternative to straight TCP/IP where the network providers would count data differently somehow?