How do mobile operators interact with each other?

Question

Megaphone

I read that each operator has HLR and VLR registers needed for switching.
But how does the switching of the call of different operators work?
Or are HLR and VLR common to all operators?

Answer 1

Have you noticed the difference in connection time with someone else's operator? it is longer. I assume that one operator sends a request to another that looks at whether there is such a number or not. if there is, it returns the data. And already your operator is processing.