12-10-2012, 04:52 PM
EQUATOR (EQUivalent servAnt locaTOR)
1. INTRODUCTION
This paper focuses on services provided by equivalent servants and models and analyzes the performance of structured and unstructured overlays when used to provide such services. We demonstrate that the architecture chosen for the P2P network has a huge impact on the overall performance of the service. In particular, with the support of some analytical and simulation results, we show how an unstructured network based on epidemic dissemination and built over a scale-free overlay topology is an effective solution to deploy in this context. Then, we present EQUATOR (EQUivalent servAnt locaTOR), a P2P-based architecture deployable in real networks for the provision of services based on equivalent servants. EQUATOR aims at guaranteeing high lookup performance, as well as high robustness to failures and churn phases, when a significant number of peers joins/leaves the network.
Existing works lack in providing adequate support to these emerging distributed systems. In fact, most of them focus on the development of a system supporting specific requests, ranging from a unique specific file to a set of resources characterized by well-defined parameters. While these systems can also support the localization of equivalent servants, they are not optimized for this purpose because of the different requirements they comply with, more stringent in terms of resource constraints, but simpler in terms of timely response. Hence, for example, they might be unable to locate a serving node in a very short time, such as a relay to be used in an incoming VoIP call. Furthermore, they may insert an unnecessary overhead in the servant lookup, due to the features they provide to support complex queries, which are of little help in the context of services based on equivalent servants.