WS-Negotiation: an overview of research issues

A Web service is defined as an autonomous unit of application logic that provides either some business functionality or information to other applications through an Internet connection. Web services are based on a set of XML standards such as Simple Object Access Protocol (SOAP), Universal Description, Discovery and Integration (UDDI) and Web Services Description Language (WSDL). In particular, Web services discovery is the process of finding most appropriate Web services providers needed by a Web services requestor. One of the important issues in the discovery process is for Web services providers and Web services requestors to negotiate and find a solution that is acceptable to both sides. Thus, a more sophisticated business model with negotiation feature is required for this challenging research area. As there are increasing demands for negotiation technologies in the context of Web services, this paper proposes an independent declarative XML language called WS-Negotiation for Web services providers and requestors. In general, WS-Negotiation contains three parts: negotiation message, which describes the format for messages exchanged among negotiation parties, negotiation protocol, which describes the mechanism and rules that negotiation parties should follow, and negotiation decision making, which is an internal and private decision process based on a cost-benefit model or other strategies. This paper also presents a service level agreement (SLA) template model with different domain specific vocabularies for supporting different types of business negotiations in WS-Negotiation.