Designing Resilient Overlay Networks for Peer-to-Peer Applications
Peer-to-peer (P2P) overlay networks are the basis of numerous large-scale distributed applications since they provide the ability to share resources, distribute content, and offer collaborative services without a central authority. Nonetheless, due to the openness and dynamism nature of P2P systems, they are very susceptible to failures, node churning, network partitions and maliciousness. Creation of robust overlay network is hence critical in ensuring reliability, availability and performance during unfavorable conditions. In this paper, the design principles, threat models and protocol mechanisms necessary to create fault-tolerant and secure P2P overlays are investigated. It initially examines the main properties of structured and unstructured overlay networks with emphasis made to the topology construction of the networks, their maintenance mechanisms, and their routing mechanism. This paper will then examine some of the most critical failure and attack models such as dynamic membership changes, link failures, Byzantine nodes and coordinated attacks, which worsen overlay performance. Based on this discussion, the paper provides resilient protocol architecture design of join, leave, and reconfiguration procedures, and fault-tolerant routing and look-up algorithms, including Chord successor list routing, k-redundant path routing, and self-healing overlay routing. The issue of security conscious resilience mechanisms is also discussed to reduce malicious behavior without compromising scalability. As an analytical discussion and comparative assessment results in, the findings indicate that redundancy, adaptability and self-healing properties can enhance overlay robustness without incurring too much overhead. At the end of the paper, design trade-offs and future directions of resilient P2P overlay networks in new decentralized applications have been highlighted.