An Analytical Study of a Structured Overlay in the presence of Dynamic Membership

TL;DR

This paper provides an analytical framework for understanding the effects of dynamic membership on structured peer-to-peer networks, specifically applying a fluid model to predict network stability and lookup performance under churn.

Contribution

It introduces a fluid model approach to analyze churn effects in structured overlays, accurately predicting disconnection probabilities and pointer failures, validated by simulations.

Findings

Accurately predicts network disconnection probabilities under churn.

Quantifies the impact of churn on successor and finger pointer correctness.

Validates theoretical predictions with simulation results.

Abstract

In this paper we present an analytical study of dynamic membership (aka churn) in structured peer-to-peer networks. We use a fluid model approach to describe steady-state or transient phenomena, and apply it to the Chord system. For any rate of churn and stabilization rates, and any system size, we accurately account for the functional form of the probability of network disconnection as well as the fraction of failed or incorrect successor and finger pointers. We show how we can use these quantities to predict both the performance and consistency of lookups under churn. All theoretical predictions match simulation results. The analysis includes both features that are generic to structured overlays deploying a ring as well as Chord-specific details, and opens the door to a systematic comparative analysis of, at least, ring-based structured overlay systems under churn.