Self-Organization in Overlay Networks

Overlay networks are an important kind of P2P infrastructures. The range of applications and requirements is broad. Consequently, our research objective are overlay networks which organize and adapt themselves at runtime. This article describes the current state of our project and gives an overview of the steps envisioned. We briefly show the necessity for self-organization in overlay networks. Based on our experience, we then provide a list of overlay network system parameters relevant for dynamic adjustment. When designing mechanisms for self-adaptation for overlay networks, we have observed implementationlevel interference and semantic-level interference. To deal with these phenomena, the overlay network architecture envisioned (1) must separate functionality for self-organization and system core functionality and (2) should preserve system integrity. To achieve this, we propose to use self-tuning mechanisms with explicit preand postconditions and conflict resolution as well as reflection. We discuss alternative implementation techniques and present one concrete approach based on AspectOriented Programming and Mixin Layers. We conclude with first insights into organic overlay networks and emergent behavior.