Jeudi 11 juin 2015 à 11h, salle 24-25/405
Abstract
In superpeer based p2p networks, the superpeer nodes are discovered through the process of bootstrapping, whereby resourceful peers get upgraded to superpeers. However, bootstrapping is influenced by several
factors like limitation on the maximum number of connections a peer can
have due to bandwidth constraints, limitation on the availability of
information of existing peers due to cache size constraints and also by the
attachment policy of the newly arriving peers to the resourceful peers. In
this talk we propose an analytical framework which explains the emergence
of superpeer networks on execution of the commercial peer-to-peer
bootstrapping protocols by incoming nodes. Bootstrapping protocols exploit
physical properties of the online peers like resource content, processing
power, storage space, connectivity etc as well as take the finiteness of
bandwidth of each online peer into consideration. With the help of rate
equations, we show that execution of these protocols results in the
emergence of superpeer nodes in the network - the exact degree distribution
is evaluated. We also show that the cache parameters must also be suitably
tuned so as to increase the fraction of superpeers in the network. We
validate the developed framework through extensive simulation. The analysis
of the results shows that the amount of superpeers produced in the network
depends on the protocol as well as the properties of the joining nodes. As
an application study, we show that our framework can explain the
topological configuration of commercial Gnutella networks.