Séminaire REGAL


D1HT: A Distributed One Hop Hash Table (*)

Tuesday, April 24, 2007
Speaker(s) : Claudio Amorim (**), Universidade Federal do Rio de Janeiro

Distributed Hash Tables (DHTs) provide scalable and practical solutions to store, locate, and retrieve information widely dispersed in large-scale distributed environments. For this reason, DHTs have already been proposed for a variety of distributed and P2P applications, including grids, distributed storage systems, file sharings, Internet games, among others. This multitude of applications place DHTs as a useful distributed software. However, most of DHTs so far have opted to solve lookups with multiple hops, which sacrifices performance in order to keep little routing information and minimize maintenance traffic.
In this seminar, I will present D1HT, a novel single hop DHT that we have developed at COPPE-UFRJ. I will show that D1HT is able to maximize performance with reasonable maintenance traffic overhead even for huge and dynamic P2P systems. We formally defined the algorithm we proposed to detect and notify any membership change in the system, proved its correctness and performance properties, and introduced a Quarantine-like mechanism to reduce the overhead caused by volatile peers.
I will show results of our analyses that demonstrate that D1HT has reasonable maintenance bandwidth requirements even for large systems, while presenting at least twice less bandwidth overhead than previous single hop DHT.

(*) partial results of this work were presented firstly at the 20th IEEE IPDPS, 2006. ----------------------------------------------- (**) Claudio Amorim is associate professor in the Systems and Computer Engineering Program at COPPE-Federal University of Rio de Janeiro. He received the MSc and PhD degrees in computer science at Imperial College, London/UK, in 1980 and 1984, respectively. His current research interests include high-performance cluster computing, and scalable servers for multimedia and e-commerce applications. He holds five patent applications and published over 90 technical papers in conferences and journals, 2 books (in Portuguese) on advanced computer architecture. He is a member of the Brazilian Computer Society and the IEEE. More information can be found at www.cos.ufrj.br/~amorim .

Bertil.Folliot (at) nulllip6.fr