Research On The Mechanism Of Service Discovery

Service discovery linking service providers and requestors is critical element in large scale, open distributed systems such as grid infrastructure and services framework. This report proposes a classification of service discovery according to the numbers of service providers and service requestors based on the analysis to existing service discovery, further propose three approaches to discover service, they are MS, D~2 and Us respectively.MS is a consumer-oriented mechanism of service discovery. It built at the side of service consumer, and is only used by consumer himself. It stores information about the services accessed by the consumer, and information marked by consumer in person locally. By use of this mechanism, one can find service by name or keywords given locally, and can make use of the consumer's experience.D~2 is a mechanism of service discovery for a group of services, which may be used substitutionally each other under given condition. For service requestor, it is an abstract service that can be access as an ordinary service. When the abstract service is requested, the D~2 finds a concrete service registered in it ant offers the functionality requested by the requestor. Its registry contains information of one or more concrete service. When a concrete service is registered, one or more of the three kind of description about the services must be provided in order to implemented substitution. This service discovery can help to process some problems concerning to meaning of different arguments.Us aims to give service requestors a friendly interface to find service from it. Its user can find service by local description, so user doesn't need know global information about services. Us maintains an element that mapping local description to global description, and implements service discovery. With this discovery, it is easy to construct a two-level authentication system, reducing the burden of service provider that to maintain a large amount information of users locally.Service discovery is essential to services systems, so we must do further researches to build convenient service discovery. We believe that service discovery is the key factor for the evolution of service system.