Peer to peer systems

The peer-to-peer (P2P) paradigm has been proposed as a powerful approach to build highly scalable and fault tolerant systems. Our research focuses on three important topics in P2P systems:

  • Workload characterization of P2P file sharing traffic. File sharing has emerged as one of the killer applications of P2P networks. File sharing traffic presents significant differences with respect to traditional Web traffic, hence traditional Web workload analyses are not useful to understand the characteristics of file sharing traffic. Our goal is to design innovative techniques and develop new models to characterize P2P traffic.
  • Innovative overlay routing mechanisms. Standard overlay routing techniques are characterized by either low efficiency (as in the case of flood-based queries, that generates large amount of traffic) or by lack of flexible search semantics (such as Distributed Hash Tables -- DHTs that requires the exact key of the object to be retrieved). We aim to design and and evaluate novel routing algorithms with the following features:
    • support for flexible query. In particular we focus on supporting multiple keywords-based searches
    • high efficiency. We aim to achieve an overhead (measured in messages per query) comparable to DHTs
    • Simple deployment. We focus on algorithms that can be introduced on top of existing DHTs without the need to introduce completely new algorithms or data structures.
  • Simulation of P2P networks. The study of P2P is characterized by difficulties due to the complex nature of such systems and due to the high number number of nodes involved in overly networks. Analytical models are often too complex to be handled, while a prototype approach is generally impossible do carry out due to unaffordable number of nodes to deploy. We are developing a simulator that aims to be able to provide a detailed model f P2P networks (considering even low-level network effects) while preserving the ability to simulate large P2P networks.


Selected Papers

  • M. Andreolini, R. Lancellotti, "A flexible and robust lookup algorithm for P2P systems" Proc. of the 23rd IEEE International Parallel and Distributed Processing Symposium (IPSPS 2009) -- DPDNS workshop, Rome, Italy, May 2009
  • M. Amoretti, R. Lancellotti "A ns2-based simulation framework for overlay networks" Technical report TR-56-2006, Presented at the Web-Minds Meeting, Genova (IT) October 2006
  • Mauro Andreolini, Michele Colajanni, Riccardo Lancellotti, "Peer-to-Peer workload characterization: techniques and open issues", Proc. of International Workshop on Hot Topics in Peer-to-Peer Systems (In conjunction with MASCOTS 2004) Volendam (NL), October 2004
  • Mauro Andreolini, Riccardo Lancellotti, Philip S. Yu, "Analysis of peer-to-peer systems: workload characterization and effects on traffic cacheability", Proc. of 12th Annual Meeting of the IEEE / ACM International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS 2004) Volendam (NL), October 2004

Riccardo Lancellotti