E-Supply Chain Orchestration Using Web Service Technologies: A Case Using BPEL4WS

The world today is witnessing a growing interest in conducting supply chain business processes electronically. Different supporting technologies are emerging, and many are already available on the market. The adoption of these technologies is hampered by the fact that organizations demand that their data and inner business processes remain hidden. Recent research and innovations have shown that Service Oriented Architectures (SOA) and Web Services can address the major issues encountered in complex supply chains. One of the largely unsolved issues is the orchestration of the variety of Web Services in the supply chain. This paper presents an investigation on orchestration of supply chain business processes using the Business Process Execution Language (BPEL). A fictitious but realistic case study was used to demonstrate and test the orchestration of an end-to-end supply chain though BPEL for Web Services (BPEL4WS). INTRODUCTION Trends indicate that one of the major ‘means of survival’ organizations use in the current business era, is creating alliances with partners so as to form business networks (Hengst et al, 2001). As a result, operational business processes tend not to be self-contained within an organization. They have to include external partner processes that have a limited visibility. This increases the difficulty for decision makers to understand and re-design the operational processes in the business network. In addition, the dynamic nature of the business network, e.g. a changing number or types of partners, or an involvement in several networks, increases the difficulty and complexity. Unlike previous approaches and technologies, the emerging Service Oriented Architecture (SOA) and Web Service technology significantly decreases the difficulty decision makers face, by addressing key business network issues such as interoperability, scalability, heterogeneity, and decoupling of information systems. Previous component-based middleware and web technologies have proved to be insufficient for the integration of business processes and applications at inter-organizational level (Stal, 2002). Integration of different data models, workflow engines, or business rules are some of the issues. Web-services technology has shown to contribute to the solution of the mentioned challenges. Web services are self-contained, web-enabled applications capable not only of performing business activities on their own, but also possessing the ability to engage other web services in order to complete higher-order business transactions (Yang, 2003). Orchestration specifications and technologies of web services enable loosely coupled business processes and applications with much less effort compared to previous technologies. Therefore, it is the aim of this paper to demonstrate the feasibility and applicability of orchestration supported by the Business Process Execution Language (BPEL) within a case study. BACKGROUND Different middleware technologies have been researched and applied to enhance and support the supply chain business processes operations (Serian, 2002; Linthicum, 1999). CORBA, RMI, EDI, and RPC are just a few of the examples. Though these technologies were used for integration purposes, they don’t address interoperability issues that are key in business networks consisting of several partners each using different type of applications and information systems infrastructures (Stal, 2002). SOA and web service technology promises to solve these problems (Rhody 2002). The technology facilitates interactions and sharing of information in a heterogeneous environment. Supply chain process partners need to share and access information like stock levels and inventory. Web services can ‘glue together’ applications running on two different platforms, enable database information to be accessible to others, and enable internal applications to be made available over the Internet (Kreger, 2003). Papazoglou et al (2003) stress the importance of SOA and web services with regards to business processes like supply chains. They covered the issue of coordination, monitoring, conformance, and quality of service compositions. Meredith et al. (2003) point out how contracts and trust can be reached between partners using web service for their business processes. Various architectures for the technology lay out and their corresponding programming languages have been researched. Current architectures have gone further covering quality of services, security, management, business level agreements, service level agreement, etc, (Kreger, 2003). Researchers have also focused on standardizing protocols, languages, models, etc., for proper use of the technology in the area of coordination. Curbera et al (2003) point out the need of web service technology in business processes and the standards that these business processes should follow to efficiently utilize the web service technology. They focus on business-to-business and enterprises applications integrations. They further mention that XML is becoming the standard interoperable programming language and consequently SOAP, UDDI, WSDL, and BPEL4WS have deployed the language. With these developments towards standardization, companies are investing to see the technology working. IBM and Microsoft work concurrently on making the business process execution language (BPEL) and its supporting tools popular and standard (IBM, 2001). Supply chain management systems are technologies that are also used for business process integration. Though this technologies are already used widely, their main focus is not in process orchestration and automation; instead on integration of ERPs and other information systems of supply chain partners. This gives web services and particularly web-service BPEL a unique position in addressing automation and orchestration business processes in business networks. 701 E. Chocolate Avenue, Suite 200, Hershey PA 17033, USA Tel: 717/533-8845; Fax 717/533-8661; URL-http://www.idea-group.com ITP5183 IDEA GROUP PUBLISHING This paper appears in Managing Modern Organizations Through Information Technology, Proceedings of the 2005 Information Resources Management Association International Conference, edited by Mehdi Khosrow-Pour. Copyright 2005, Idea Group Inc. Managing Modern Organizations With Information Technology 283 Copyright © 2005, Idea Group Inc. Copying or distributing in print or electronic forms without written permission of Idea Group Inc. is prohibited. SOA AND WEB SERVICES A Service Oriented Architecture (SOA) is essentially an architecture which describes the communication pattern between services communicating with each other, functions and their operations (Papazoglou et al, 2003). These architectures provide the ability to register, discover, and use services, where the architecture is dynamic in nature (O’Toole, 2003). In the perspective of SOA a service is a function that is well defined, selfcontained, and does not depend on the context or state of other services. SOA do not have any specific technology or a description language. Before, services were conducted and worked only on the environment of the origin programming languages. SOA defines how two computing entities interact in such a way that it enables one entity to perform a unit of work on behalf of another entity. The unit of work is referred to as a service, and the service interactions are defined using a description language. Each interaction is self-contained and loosely coupled, so that each interaction is independent of any other interaction. Web service technology facilitates collaboration between services and their orchestration and in addition defines how to describe these services, the operations and their flows. It uses a loosely coupled integration model that allows flexible integration of heterogeneous systems in a variety of domains including business-to-business, business to customer and enterprise application integration (IBM, 2001). Web service technology is an Internet technology, which allows applications based on it to communicate with other applications to offer business data or functional services programmatically (Jin, et al, 2002). As a web based technology, web service technology includes all the network layers, but on top various authors have added specific layers that make uniquely suitable for facilitating business processes. These layers include a process layer, a description layer and a messages layer, etc., (Curbera, 2003). Martin (2003) described further the additional layers to Curbera relating to the technology components and functions, such as presentation, process flow, transaction, discovery, description, messaging and transport. Furthermore, Kreger (2003) added businessand service-level agreements as technology components. This paper focuses on orchestration of a supply chain case. Orchestration describes how web services can interact with each other at the message level, including the business logic and execution order of the interactions (Peltz, 2003). These interactions may span applications and/or organizations, and result in a long lived, transactional, multi-step process model. Another aspect is choreography which tracks the sequence of messages that may involve multiple parties and multiple sources, including customers, suppliers, and partners (Peltz, 2003). Choreography is typically associated with the public message exchanges that occur between multiple web services. In this paper orchestration refers to both aspects. With these aspects, two layers will be described further. The description layer uses a language called web service description language (WSDL), and its function is to provide a grammatical description of a service given at one point in the network of web service based business processes. The Process flow layer provides the orchestration of activities to be performed within a node and between nodes in the network. Process flow layer has several mod