Distributed Service Discovery with Guarantees in Peer-to-Peer Networks using Distributed Hashtables

摘要

In this paper we propose a protocol for service discovery in decentralized environments. Our protocol guarantees that service descriptions can be found by any node in the network. It is meant to be used by applications which cannot afford central components, e.g. due to ad-hoc formation. The protocol makes use of the structured overlay network Chord. Chord has logarithmic performance for looking up keys with respect to the number of nodes and guarantees to retrieve any entry stored in the network. This would not be possible in an unstructured overlay network without flooding the whole network. Service descriptions are decomposed into portions which can be efficiently distributed and retrieved. Though this implies additional costs for publishing of service descriptions, it improves efficiency of lookup operations. We implemented a Java prototype of our protocol as a proof of concept based on TCP/IP.