@alexhall Phone extensions is the one I always go for. Hotels can't afford assigning a real phone number to every room, just as we can't afford assigning a separate IPV4 to every computer. Private IP addresses are like internal extensions that you can only call from a phone line in the hotel. Everybody is still permitted to call out, and their caller ID will appear as the main number for the hotel.
@alexhall This is kind of confusing when you get to ports (which are actually a lot more like phone extensions). But ehh what can we do, every metaphor breaks down at some point.