Publish-subscribe for mobile environments

The Publish-Subscribe paradigm has become an important architectural style for designing distributed systems. In the recent years, we are witnessing an increasing demand for supporting publish-subscribe for mobile computing devices, where conditions used for filtering the data can depend on the particular state of the subscriber (quality of the connection, space and time locality, device capabilities). In this paper we present a stateful model for publish-subscribe systems, suitable for mobile environments. In our system, the server maintains a state for each client, which contains variables that describe the properties of the particular client, such as the quality of the connection or the display size. The interest of each client can be expressed in terms of these variables. Based on the client interests, an associated agent is created on the server. The agent filters the data that reach the client based on the current client state. Experimental results show good performance and scalability of our approach.