I am currently writing a report abour DataAccess and Communication between a Flex based Application and server-side code.
In the Manual I found information about:
How does the NetConnection and the term Messaging match into this ?
NetConnection has no relation to the above three RPC methods. Its a class used for making a connection between FMS (Flash Media Server) and Flex application.
Messaging is the term associated with BlazeDS. It provides publish/subscribe mechanism with flex application & server. See http://livedocs.adobe.com/blazeds/1/blazeds_devguide/help.html?content=lcoverview_4.html for more details.