Comprehending Kademlia Routing - A Theoretical Framework for the Hop Count Distribution

TL;DR

This paper presents a formal model of Kademlia routing, analyzing hop distributions and delays, revealing insights into protocol improvements and guiding better design choices for efficiency and resilience.

Contribution

It introduces the first comprehensive formal model of Kademlia routing, validated against measurements, and evaluates protocol improvements for efficiency and robustness.

Findings

Validated the formal model against real measurements

Identified some recent improvements as counter-productive

Suggested preferable designs for routing overhead and resilience

Abstract

The family of Kademlia-type systems represents the most efficient and most widely deployed class of internet-scale distributed systems. Its success has caused plenty of large scale measurements and simulation studies, and several improvements have been introduced. Its character of parallel and non-deterministic lookups, however, so far has prevented any concise formal analysis. This paper introduces the first comprehensive formal model of the routing of the entire family of systems that is validated against previous measurements. It sheds light on the overall hop distribution and lookup delays of the different variations of the original protocol. It additionally shows that several of the recent improvements to the protocol in fact have been counter-productive and identifies preferable designs with regard to routing overhead and resilience.