HSIENA: A hybrid publish/subscribe system

The SIENA publish/subscribe system represents a prototypical design for a distributed event notification service implementing the content-based publish/subscribe communication paradigm. A clear shortcoming of SIENA is represented by its static configuration that must be managed and updated by human administrators every time one of its internal processes (brokers) needs to be added or repaired (e.g. due to a crash failure). This problem limits the applicability of SIENA in large complex critical infrastructures where self-adaptation and -configuration are crucial requirements. In this paper we propose HSIENA, a hybrid architecture that complements SIENA by adding the ability to self-reconfigure after broker additions and removals. The architecture has a novel design that mixes the classic SIENA's distributed architecture with a highly available cloud-based storage service. © 2012 Springer-Verlag Berlin Heidelberg.