I have two iPhones, a 6 Plus and a 7 Plus. My apartment is long and narrow, so my internet provider's router and WiFi AP will not cover the whole place effectively. I am using an Airport Extreme in bridge mode in my living room, with internet signal coming through Ethernet, to get a reliable signal there. So, here is the question. While both iPhones connect to the internet provider's AP without issues on the 2.4GHz network (5GHz is available), they each connect to a different network, iPhone 6 Plus on 2.4 GHz, and the 7 Plus on 5 GHz, on the Airport Extreme. If I try to force connect them to the "other" network, they briefly jump back to 4G and then reconnect to their "preferred" network. There is no problem here, and they both work just fine as things stand. But is there any way to better understand how iPhones connect to WiFi AP? And if one network can be prioritised over another?