Service Composition in a Global Service Discovery System

GloServ is a global service discovery system which aggregates information about different types of services in a globally distributed network. GloServ classifies services in an ontology and maps knowledge obtained by the ontology onto a scalable hybrid hierarchical peer-to-peer network. The network mirrors the semantic relationships of service classes and as a result, reduces the number of message hops across the global network due to the domain-specific way services are distributed. Also, since services are described in greater detail, due to the ontology representation, greater reasoning is applied when querying and registering services. In this paper, we describe an enhancement to the GloServ querying mechanism which allows GloServ servers to process and issue subqueries between servers of different classes. Thus, information about different service classes may be queried for in a single query and issued directly from the front end, creating an extensible platform for service composition. The results are then aggregated and presented to the user such that services which share an attribute are categorized together. We have built and evaluated a location-based web service discovery prototype which demonstrates the flexibility of service composition in GloServ and discuss the design and evaluation of this system. Keywords: service discovery, ontologies, OWL, CAN, peer-to-peer, web service composition