@Vostok and @RichardV you are of course correct that all app related comms goes via the Tesla VPN, I didn't think of that when I made my earlier statements. But the mystery isn't that easily solved... Just did a quick test on the browser in the car and it's connecting from 1.144.x.x range of Telstra IP's, so indeed Telstra are the local provider. That however still does not preclude that Tesla have bulk purchased from a different (overseas) provider and the cars are in fact roaming here. Many IoT companies are doing deals of that sort.
Going to speedtest.net with the built in browser is showing excessively long ping times for me (700ms and more) and the bandwidth is atrocious - but that is true both with the car connected to Wifi with my Telstra AP, and with the car's own LTE, so could be down to the embarrassingly underspecced Atom processor used for the MCU.
Have a look at how the attached IP architecture in LTE networks diagram. The mobile node in a foreign network is routing all traffic via the home network (which is why our roaming overseas is dead beat unusuable) - but will still show a local provider's IP address as the end point.
Going to speedtest.net with the built in browser is showing excessively long ping times for me (700ms and more) and the bandwidth is atrocious - but that is true both with the car connected to Wifi with my Telstra AP, and with the car's own LTE, so could be down to the embarrassingly underspecced Atom processor used for the MCU.
Have a look at how the attached IP architecture in LTE networks diagram. The mobile node in a foreign network is routing all traffic via the home network (which is why our roaming overseas is dead beat unusuable) - but will still show a local provider's IP address as the end point.