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SEMINARIO DI INFORMATICA
Mercoledì 10 Giugno 2015 alle ore 14:00 in Aula 1BC45, Ding Ding (University of Padua) terrà un seminario dal titolo "Impact of Country-scale Internet Disconnection on Structured and Social P2P Overlays".
Peer-to-peer systems are resilient in the presence of churn and uncorrelated failures. However, their behavior in extreme scenarios where massive correlated failures occur is not well-studied. Yet, there have been examples of situations where a country-scale fraction of Internet users have been disconnected from the rest of the network—for instance, when a government cuts connectivity to the outside world as a mechanism for suppression of uprisings.
In this paper, we consider the effect of such partitions on topology and routing of structured and social-based unstructured P2P overlays, including a novel social-aware overlay. In particular, we consider nodes within a relatively small fraction of the network (2.5% or fewer Internet users), and study whether users can communicate with their (n-hop away) social neighbors in a peer-to-peer fashion after the partition. We perform an extensive simulation-based analysis to assess the probability for these communications to be possible. In our analysis, we consider both real and synthetic datasets of online social networks. Our results show that structured P2P overlay routability is severely hampered by country-scale partition events. In addition, the proposed social-based unstructured overlay network provides improved routability while maintaining a smaller number of links.