Bandwidth and Latency Model for DHT Based Peer-to-Peer Networks under Variable Churn

Distributed Hash Table (DHT) based Peer-to-Peer (P2P) algorithms are very promising for their efficient routing performance. However, most commercial P2P systems do not adapt DHT algorithms due to reasons like routing information maintenance overhead, considerable network traffic and increased P2P system complexity in a highly dynamic environment. The dynamics of peer participation (churn) is an inherent property of P2P systems that should be incorporated in the design and evaluation of DHT-based structured P2P overlay networks. In this paper, we study the effect of variable churn on DHT updation and lookup latency due to non-uniform bandwidth nodes randomly joining and leaving the P2P network. We further study the effect of non-uniform node bandwidth in handling churn related DHT communications, flash crowd requests and study the tradeoff between bandwidth and latency for evaluating DHT performance during variable churn. We employ a Modified Pareto distribution to determine probability of node liveness based on its current lifetime in the P2P network.