Semantic-Based Scalable Decentralized Resource Discovery

Resource Discovery (RD) is a key issue in Grid
systems since resource reservation and task scheduling are
based on it. RD is about locating an appropriate resource type
that match the user’s application requirements. Currently, most
Grids RD adopt a centralized or hierarchical model. However,
this model is characterized by poor scalability, dynamism and
decentralization features. Moreover, they do not support
semantic description and discovery. This paper proposes a new
semantic-based scalable decentralized Grid RD model. Grid
nodes are classified into classes based on some criteria; each
class has a head, which is elected among its own class
nodes/members. Peer-to-Peer (P2P) network architecture is
used. The architecture has two layers; the first is to connect
between the class heads and the second between each class
members. Ontology is used to describe the resources,
applications and their relationships. We introduce two kind of
intelligent agents; Request Agent (RA) and Description Agent
(DA). Each node has both of the agents. DA describes resource
capabilities, and RA carries resource requests that are needed
for some applications. We develop a RD algorithm that
optimizes the search of the resources on the network. Our
discussion shows how the new model satisfies Grid RD features
such as scalability, decentralization, dynamism and
interoperability.