Prof. Dr. Ralf Steinmetz

"P2P communications need well designed and qualityaware overlay networks"

The topic of this talk is about efficient communication mechanisms and design techniques for P2P overlay networks. A short introduction of the basic properties and characteristics of P2P systems is initially provided, followed by an illustrative analysis of the challenging issues in the design of P2P overlay networks. Then, a novel architecture for overlay network design is presented that follows a hybrid approach to address the large number of conflicting non-functional requirements. Such conflicts are often present in P2P systems operating in large-scale, evolving and heterogeneous environments. Our approach extends the well-known de Bruijn digraphs and adapts them to the needs of a variety of P2P systems. We present the suggested two-tier topology and its related attractive characteristics and analyze the operations of the core algorithms aiming at the smooth operation under challenging conditions of concurrent events. We then discuss a supplementary set of mechanisms for peer clustering and we suggest a novel responsibility distribution technique that takes into account the heterogeneity of the participating peers to achieve an efficient and fair load balance. The talk ends with the brief presentation of the related activities investigated by our institute, such as accounting, security and replication in the P2P context.