COPS09 Final Report
From P2P Wiki
Pedro García López
Departament d'Enginyeria Informàtica i Matemàtiques University Rovira i Virgili, Spain pedro.garcia@urv.cat
Contents |
Introduction
The workshop is a small, high quality and interactive meeting for novel P2P ideas and proposals. On the one hand, Collaborative P2P systems aim to benefit from the huge amount of unused resources of desktop computers (content, data storage, cpu, bandwidth) to create the next generation of Internet Infrastructures. On the other hand, P2P is particularly challenging for developing collaborative information systems. In this line, P2P can be used to create social networks and communities, to discover users and information, to aggregate community contents or even as a communication medium for large groups.
The fifth International Workshop on Collaborative Peer-to-Peer Systems has attracted high quality submissions from top research groups around the world. It received 27 submissions from 14 countries and it is creating a vibrant community of researchers in the peer-to-peer topic. After the review process, 10 full papers, and 1 short paper were included in the final program.
The high quality submissions have demonstrated the relevance of the topic and the recent trends in the peer-to-peer research community. The workshop was divided in three sessions: algorithms, middleware and security. Every paper addresses a hot topic in peer-to-peer research and relevant researchers in the area presented their recent contributions.
P2P Algorithms
David Hales et al presented the paper entitled "BitTorrent or BitCrunch: Evidence of a credit squeeze in BitTorrent?". They identify the possibility of a credit squeeze in BitTorrent in which performance is reduced due to lack of credit for some peers. This credit squeeze happens because private trackers impose credit policies that see the performance of the community as a whole.
Neil Cowzer et al presented the paper entitled "GeoIGM: a Location-Aware IGM Platform". They present a novel peer-to-peer system, GeoIGM, well suited to the highly collaborative style of tagging and development of context-aware services, particularly location. With the provision two fundamental operations; geographically-scoped multicasting and queries, GeoIGM eases the development of next-generation location-aware systems.
Nuno Lopes et al presented a paper entitled "Search Optimizations in Structured Peer-to-Peer Systems". They present a distributed data structure based on a decentralized balanced tree to balance storage data and network load more uniformly across hosts. The results show that the data structure is capable of balancing resources, in particular when performing multiple keyword searches.
Shay Horovitz et al presented a paper entitled "Collabrium: Active Traffic Pattern Prediction for Boosting P2P Collaboration". They present Collabrium - a collaborative solution that employs a machine learning approach to actively predict load in the uplink of source peers and alert their clients to replace their source.
P2P Middleware
Gerald Oster et al presented a paper entitled "UniWiki: A Collaborative P2P System for Distributed Wiki Applications". They present a peer to peer solution for distributing and managing dynamic content, that combines two widely studied technologies: distributed hash tables (DHT) and optimistic replication. The implementation is based on a Distributed Interception Middleware, thus separating distribution, replication, and consistency responsibilities.
Syed Muhammad Ali Abbas presented a paper entitled "A gossip-based distributed social networking system". They present an alternative approach, based on gossip protocols, in which they use a completely decentralized peer-to-peer system to create and store the social network. They show the design and implementation in Tribler of a distributed social networking system that is scalable and robust, allowing users to perform core social networking functions of establishing and removing social links without any requirement for centralized servers or administration.
Mirko Knoll et al presented a paper entitled "Bootstrapping in Peer-to-Peer Systems". They present a novel bootstrapping algorithm that builds on the Internet Relay Chat (IRC), a highly available, open, and distributed network of chat servers. The algorithm is designed to put only a very minimal load on the IRC servers while achieving scalability.
Security
Nouha Oualha et al presented a paper entitled "A Game Theoretical Approach in Securing P2P Storage against Whitewashers". Authors present a novel penalty mechanism against strangers and they describe as well a theoretical game that models such mechanism and attempts to capture the point of tradeoff between restricting whitewashers and encouraging newcomers to participate into the system.
Gian Paolo Jesi et al presented a paper entitled "Secure Peer Sampling Service: the Mosquito Attack". Authors present a novel attack that benefits from the skewed distribution between publicly available peers and others behind firewalls. Peer sampling is thus limited to peers that are freely accessible, while the others only play a limited role. The existence of these two groups, with different roles and sizes, enables one group to exploit the other.
Joan Arnedo-Moreno et al presented a paper entitled "Maintaining unlinkability in group based P2P environments". They describe a method in order to maintain unlinkability in group membership authentication attempts when using peer groups relying on web-of-trust. Using this method, it is not possible to ultimately pinpoint a peer's identity despite the constraints of a group membership scenario.
Thomas Bocek et al presented a paper entitled "Incentives for Voting-based Quality Control and Document Storage in P2P Collaboration Systems". This position paper proposes a score-based incentive scheme for voting-based quality control and document storage in a P2P-based collaboration system. The approach is based on the PeerVote mechanism, which enables users to vote on content modifications.
Conclusions
The COPS workshop is consolidating a strong community of top researchers around the hot topic of Peer-to-Peer Systems. Top research groups in peer-to-peer systems and key European Research projects like P2PNext and NapaWine were represented in the workshop.
Peer-to-peer is transversal to many disciplines like Grid systems, pervasive environments, social networks and large-scale decentralized systems. In this line, peer-to-Peer features like decentralization, self-management, or scalability make this field very important for the Internet of the Future.
Finally, the COPS09 best paper was awarded to "A Game Theoretical Approach in Securing P2P Storage against Whitewashers". Evolutionary game theory is an exciting field of research for peer-to-peer systems where peers can choose to cooperate or compete for the shared resources. Authors presented an interesting evolutionary game that attempts to capture the point of tradeoff between restricting whitewashers and encouraging newcomers to participate in P2P Storage.
