[#3Fan]

And the odds are that both the MAP messaging which allows you to roam and send SMS is going through a system that I spent the last 3+ years of my life developing, testing, debugging, enhancing, supporting, etc.

What is the general description of MAP messaging?

[KayEyeDoubleDee]

MAP is Mobile Application Protocol. It is the very high level protocol which, in particular, allows customers to roam between networks. In GSM and IS-41 (the latter of which is used by the earlier TDMA systems) it also deals with supplimentary services, SMS, and provides some other features.

What is not very well described in this article is the seperation between the cellular infrastrucure (which includes the base stations and base station control and access to the old-school public network) and what I like to think of as the traditional SS7 network (where MAP is used).