N-tier architecture to describe an Iphone application

Question

I built a mobile application and one of the ways that i wanna explain it to people is by four-tier architecture; so after a little reading and research. From what i understood i did this design
looking at the communication between first two layers I'm not sure if i did it correctly. i think that i read somewhere that each tier have to be separated physically which obviously is not. but its satisfied that both layers can be built separately..right?

in the end is the diagram representing a four-tier architecture correctly. Thanks in advance

Answer 1

Yeah, that looks about right. The main iOS programming paradigm is model-view-controller (MVC), so you could add a controller tier in between presentation and business logic.

Answer 2

Tiers do not have to have a physical seperation so don't get too hung up on that.