2 research outputs found
On the Effectiveness of Punishments in a Repeated Epidemic Dissemination Game
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.Comment: 76 pages, extended technical report, original paper is expected to
appear on Proceedings of the 15th International Symposium on Stabilization,
Safety, and Security of Distributed Systems (SSS 2013), corrected typo in
abstract, corrected citation to Kreps:82, improved description of the stage
game to justify fixed stage strateg
On the Range of Equilibria Utilities of a Repeated Epidemic Dissemination Game with a Mediator
We consider eager-push epidemic dissemination in a complete graph. Time is
divided into synchronous stages. In each stage, a source disseminates
events. Each event is sent by the source, and forwarded by each node upon its
first reception, to nodes selected uniformly at random, where is the
fanout. We use Game Theory to study the range of for which equilibria
strategies exist, assuming that players are either rational or obedient to the
protocol, and that they do not collude. We model interactions as an infinitely
repeated game. We devise a monitoring mechanism that extends the repeated game
with communication rounds used for exchanging monitoring information, and
define strategies for this extended game. We assume the existence of a trusted
mediator, that players are computationally bounded such that they cannot break
the cryptographic primitives used in our mechanism, and that symmetric
ciphering is cheap. Under these assumptions, we show that, if the size of the
stream is sufficiently large and players attribute enough value to future
utilities, then the defined strategies are Sequential Equilibria of the
extended game for any value of . Moreover, the utility provided to each
player is arbitrarily close to that provided in the original game. This shows
that we can persuade rational nodes to follow a dissemination protocol that
uses any fanout, while arbitrarily minimising the relative overhead of
monitoring.Comment: 14 pages, 2 algorithms, accepted in ICDCN'15, proofs of D4 and D5
improved, improved definition of Non-disclosur