  This work uses Game Theory to study the effectiveness of punishments as an
incentive for rational nodes to follow an epidemic dissemination protocol. The
dissemination process is modeled as an infinite repetition of a stage game. At
the end of each stage, a monitoring mechanism informs each player of the
actions of other nodes. The effectiveness of a punishing strategy is measured
as the range of values for the benefit-to-cost ratio that sustain cooperation.
This paper studies both public and private monitoring. Under public monitoring,
we show that direct reciprocity is not an effective incentive, whereas full
indirect reciprocity provides a nearly optimal effectiveness. Under private
monitoring, we identify necessary conditions regarding the topology of the
graph in order for punishments to be effective. When punishments are
coordinated, full indirect reciprocity is also effective with private
monitoring.
