Enterprise Integration With Web Services and BPEL
Businesses looking to consolidate and modernize their applications have an alternative to EAI.
by Adam Kolawa, Ph.D.
March 14, 2005
Many companies spend enormous sums of money and collect huge amounts of data maintaining their legacy systems. Therefore, it is crucial that companies find a quick and efficient way to preserve and reuse these legacy systems rather than throwing them by the wayside. Traditionally, companies wanting to provide communication and integration across various disparate applications and operating systems have turned to enterprise application integration (EAI).
However, due to the high cost and proprietary nature of EAI solutions, companies are looking for easier and more flexible ways to consolidate and modernize their applications. In order to offer services and share data with business partners, customers, and other information systems, businesses must update their legacy systems with current technologies. A solution lies in Web services and Business Process Execution Language (BPEL). These technologies offer open, standards-based integration that provides interoperability by combining messaging technology with XML and various Web services standards. Once Web service interfaces are developed, you can use BPEL to define and orchestrate business transactions and ultimately bring the old world of legacy systems to the new world of modern information systems (see "Build Your Applications With BPEL").
This article addresses the issues that arise when integrating legacy systems with Web services, and how BPEL will play a vital role in companies' integration projects.
Integration Issues With Legacy Systems
Many of today's large businesses have existing legacy systems written in a variety of disparate languages, such as COBOL and C++. In addition, different legacy systems might be in place even where there are common interests, lending to a chaotic, decentralized IT infrastructure that makes it difficult for future integration.
For example, a typical enterprise is often composed of numerous distributed disparate departments, each department having its own processes intended to fulfill specific responsibilities. Consider a large hotel chain that offers travel services consisting of multiple information systems between businesses, departments, and applications. Each hotel has its own unique ticketing system that allows customers to perform certain actions such as viewing hotel descriptions and rates, and making and canceling reservations. However, because of each unique system, the company has difficulty maintaining and exchanging relevant data across the enterprise such as information that must be connected to an accounting system.
In the past, companies might have turned to proprietary solutions to remedy communication problems and to integrate across systems. As a result, after years of proprietary integration efforts, various integration tools and solutions exist in the enterprise today. Although it is possible to integrate isolated systems using proprietary communication (i.e., CORBA, EDI, or other message-passing technologies), companies become locked in to vendors. Expansion and growth, therefore, become increasingly difficult due to the additional amount of resources needed to maintain proprietary standards and protocols.
Creating a Web Services Interface
Businesses need scalable, reliable applications. Because so much data is involved and a large amount of resources is needed, the hotel chain in our example simply cannot start from scratch and build anew. It must find a way to extend its legacy systems and build upon them. In today's fast-moving, forward-thinking world, companies must modernize and consolidate their existing information systems. They must also ensure that, once integrated, these systems are able to provide for long-term future growth. To meet these demands, organizations must establish a flexible, standards-based architecture rather than confine themselves to proprietary fixes.
This makes the implementation of Web services an ideal choice for enterprises where multiple vendor solutions are deployed and where existing systems need to be utilized with newer applications. Web services are gaining industry-wide acceptance and usage. They are moving from proof-of-concept deployments to actual usage in mission-critical enterprise applications.
Due to the proliferation of Web service standards, such as XML, SOAP, Web Services Description Language (WSDL), and UDDI, a standardized integration interface is available that promotes and encourages interoperability and system reuse. Therefore, legacy systems can be consolidated and modernized along with newer technologies—making rapid integration possible without vendor lock-in. By building a Web services interface, you can begin to expose and build upon your legacy systems, rather than replacing them and starting from scratch. Such an architecture, therefore, provides the basis for future growth and expansion in that new applications can be easily added or plugged in due to a flexible, standards-based interface.
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