A Dependable Global Location Service using Rendezvous on Hierarchic Distributed Hash Tables

A location service is the part of a naming architecture that maps identifiers to network addresses. Ideally, the identifiers are globally unique, persistent and semantic-free. It has been acknowledged that Distributed Hash Tables (DHTs) enable, for the first time, the use of semantic-free identifiers in massive, global networks. We argue that hierarchy is essential for dependability in massive, geographically distributed DHTs. Existing hierarchic DHTs embed location information in identifiers. Consequently, if identifiers move between DHTs in the hierarchy, then the changes always propagate to the root DHT. This Location Information Plane (LIP) design is the first hierarchic DHT that contains "moves and changes" within the lower layers of the hierarchy. It protects the root DHT using the rendezvous abstraction. We show how it supports global internet telephony networks based on the Session Initiation Protocol (SIP).