Nationality of network does not matter. If you have data roaming, it doesn't matter even with the iPhone.
What is important is that you can see the videos when you're NOT in the same WAN of the camera.
You can test this even at home. If you turn the wi-fi OFF on your iPhone when you're close to the camera and make use of 3G/4G, what do you see? If the network settings are wrong, you won't see anything even if you're 1 meter from the camera, but not in the same wireless network.