Content-based publish-subscribe is emerging as a communication paradigm able to meet the demands of highly dynamic distributed applications, such as those made popular by mobile computing and peer-to-peer networks. Nevertheless, the available systems implementing this communication model are still unable to cope efficiently with dynamic changes to the topology of their distributed dispatching infrastructure. This hampers their applicability in the aforementioned scenarios. This thesis addresses this problem and presents a complete approach to the reconfiguration of content-based publish-subscribe systems. In Part I, it proposes a layered architecture for reconfigurable publish-subscribe middleware consisting of an overlay, a routing, and an event-recovery layer. This architecture allows the same routing components to operate in different types of dynamic network environments, by exploiting different underlying overlays. Part II addresses the routing layer with new protocols to manage the recon- figuration of the routing information enabling the correct delivery of events to subscribers. When the overlay changes as a result of nodes joining or leaving the network or as a result of mobility, this information is updated so that routing can adapt to the new environment. Our protocols manage to achieve this with as little overhead as possible. Part III addresses the overlay layer and proposes two novel approaches for building and maintaining a connected topology in highly dynamic network sce- narios. The protocols we present achieve this goal, while managing node degree and keeping reconfigurations localized when possible. These properties allow our overlay managers to be applied not only in the context of publish-subscribe mid- dleware but also as enabling technologies for other communication paradigms like application-level multicast. Finally, the thesis integrates the overlay and routing layers into a single frame- work and evaluates their combined performance both in wired and in wireless scenarios. Results show that the optimizations provided by our routing reconfig- uration protocols allow the middleware to achieve very good performance in such networks. Moreover, they highlight that our overlay layer is able to optimize this performance even further, significantly reducing the network traffic generated by the routing layer. The protocols presented in this thesis are implemented in the REDS middle- ware framework developed at Politecnico di Milano. Their use enables REDS to operate efficiently in dynamic network scenarios ranging from large-scale peer-to- peer to mobile ad hoc networks.
| Identifer | oai:union.ndltd.org:CCSD/oai:tel.archives-ouvertes.fr:tel-00739652 |
| Date | 18 May 2006 |
| Creators | Frey, Davide |
| Source Sets | CCSD theses-EN-ligne, France |
| Language | English |
| Detected Language | English |
| Type | PhD thesis |
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