Abstract: "Epidemic dissemination protocols are known to be extremely
scalable and robust. As a result, they are particularly well suited to
support the dissemination of information in large-scale peer-to-peer
systems. In such an environment, nodes do not belong to the same
administrative domain. On the contrary, many of these systems rely on
resources made available by rational nodes that are not necessarily
obedient to the protocol. There are two main incentive mechanisms that
can be used to deal with rational behavior. One is to rely on balanced
exchanges, which is feasible to implement in epidemic protocols where
interactions are symmetric. For the asymmetric case, incentives based on
a monitoring approach are more suited. Unfortunately, the literature
does not provide any meaningful theoretical results for this last type
of incentives. In this talk, I will present basic results that establish

a tradeoff between the amount of information provided by a monitor and
the ability to sustain cooperation among rational nodes, assuming a
perfect monitoring."

Xavier Vilaça is a PhD student at IST and a researcher of Distributed
Systems Group at INESC-ID. He got a MSc degree in Computer Science and
Engineering from IST in 2011 and a BSc also in Computer Science and
Engineering from University of Minho in 2009.

This work is being presented as a final report for the Complex Network
Analysis course from the PhD program in Computer Science and
Engineering at IST.