The evolution of publish/subscribe communication systems

In the last years, a growing attention has been paid to the publish/subscribe (pub/sub) communication paradigm as a mean for disseminating information (also called events) through distributed systems on wide-area networks. Participants to the communication can act as publishers, that submit information to the system, and as subscribers, that express their interest in specific types of information. Main characteristics of such manyto- many communication paradigm are: the interacting parties do not need to know each other (anonymity), partners do not need to be up at the same time (decoupling in time), and the sending/receipt does not block participants (decoupling in flow). So, the publish/ subscribe paradigm has been largely recognized as the most promising applicationlevel communication paradigm for integration of information systems.