ETH Zurich

Developing peer-to-peer systems is a big challenge, because they typically op-erate in large-scale, highly unreliable and insecure environments and involve the collaboration of many nodes (i.e. computers) in the network. In recent times, a lot of efforts have been devoted to the system design of peer-to-peer systems, resulting in new structured overlay networks. These overlay networks perform the routing task needed to localize items in the network efficiently even in the presence of node failures and attacks. However, to tackle the full complexity of practical peer-to-peer systems, also good software design needs to be applied. Yet, lots of peer-to-peer systems are developed in an ad-hoc manner, and little has been written about their software architecture. In this paper, I have tried to analyze the software design of overlay networks, the common abstraction of most peer-to-peer systems. Design patterns have been very successful in documenting proven and reusable solutions; consequently, I have tried to discover design patterns for overlay networks by investigating different academic and open source projects