Representational State Transfer (REST) provides a set of architectural constraints that, when applied as a whole, emphasizes scalability of component interactions, generality of interfaces, independent deployment of components, and intermediary components to reduce interaction latency, enforce security, and encapsulate legacy systems.
To know more about REST, read
http://www.ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.htm Read how to create 3 tiered REST Architecure, read
http://www.peej.co.uk/articles/3-tiered-rest-architecture.html