Instant Messaging: Architectures and Concepts

Instant Messaging (IM) is an Internet-based protocol application that allows one-to-one communication between users employing a variety of devices. (1) Recently, Instant Messaging has already obtained the remarkable success as P2P communication tool. In some places, it already took the place of e-mail as the first choice for long distance communication. In the mobile area, the Short Message Services (SMS) and Multimedia Messaging Service (MMS) also attract thousands of subscribers by the richer and richer set of services. Jabber is the most widespread open source platform, using an XML encoded protocol, especially tailored to provide instant messaging and presence services over the Internet. This paper gives some basic concepts of IM System and analyzes the basic architecture, protocol, and communication procedure based on Jabber to briefly describe the working flow of typical IM system. At the end, by comparing ICQ, MSN and Yahoo Messager - 3 most popular IM software in the nowadays market, we can get a deeper understanding of their features and working principle.