Storing and Locating Mutable Data in Structured Peer-to-Peer Overlay Networks

Structured peer-to-peer overlay networks or Distributed Hash Tables (DHTs) are distributed systems optimized for storage and retrieval of read-only data. In this paper we elaborate on a method that allows them to manage mutable data. We argue that by altering the retrieval algorithm of DHTs, we can enable them to cope with data updates, without sacrificing their fundamental properties of scalability and fault-tolerance. We describe in detail and analyze an implementation of a Kademlia network capable of handling mutable data. Nevertheless, the corresponding protocol additions can easily be applied to any DHT design. Experimental results show that although the process of managing and propagating data updates throughout the network adds up to the total cost of the lookup operation, the extra network utilization can be exploited in favor of overlay resilience to random node joins and failures.