VICINITY: A Pinch of Randomness Brings out the Structure

Overlay networks are central to the operation of large-scale decentralized applications, be it Internet-scale P2P systems deployed in the wild or cloud applications running in a controlled—albeit large-scale—environment. A number of custom solutions exist for individual applications, each employing a tailormade mechanism to build and maintain its specific structure. This paper addresses the role of randomness in developing and maintaining such structures. Taking VICINITY, a generic overlay management framework based on self-organization, we explore tradeoffs between deterministic and probabilistic decision-making for structuring overlays. We come to the conclusion that a pinch of randomness may even be needed in overlay construction, but also that much randomness or randomness alone is not good either.