Abstract

Peer-to-Peer (P2P) and Cloud Computing are two of the latest trends in the Internet arena. They both could be labelled as large-scale distributed systems, yet their approach is completely different: based on completely decentralized protocols exploiting edge resources the former, focusing on huge data centres the latter. Several Internet startups have quickly reached stardom by exploiting cloud resources. Instead, P2P applications still lack a well-defined business model. Recently, companies like Spotify and Wuala have started to explore how the two worlds could be merged by exploiting (free) user resources whenever possible, aiming at reducing the cost of renting cloud resource. However, although very promising, this model presents challenging issues, in particular about the autonomous regulation of the usage of P2P and cloud resources. Next-generation services need the possibility to guarantee a minimum level of service when peer resources are not sufficient, and to exploit as much P2P resources as possible when they are abundant. In this thesis, we answer the above research questions in the form of new algorithms and systems. We designed a family of mechanisms to self-regulate the amount of cloud resources when peer resources are not enough. We applied and adapted these mechanisms to support different Internet applications, including storage, video streaming and online gaming. To support a replication service, we designed an algorithm that self-regulates the cloud resources used for storing replicas by orchestrating their provisioning. We presented CLive, a video streaming P2P framework that meet the real-time constraints on video delay by autonomously regulating the amount of cloud helpers upon need. We proposed an architecture to support large scale on-line games, where the load coming from the interaction of players is strategically migrated between P2P and cloud resources in an autonomous way. Finally, we proposed a solution to the NAT problem that employs cloud resources to allow a node behind it to be seen from outside. Using extensive simulations, we showed that hybrid infrastructures can reduce the economical effort on the service providers, while offering a level of service comparable with centralized architectures. The results of this thesis proved that the combination of Cloud Computing and P2P is one of the milestones for next generation distributed P2P-based architectures.