In today’s e-business world, getting the right information at the right time is everything. When business transactions aren’t streamlined, accurate or efficient, organizations pay—in both time and money.
IT budgets remain static despite increasingly complex, heterogeneous infrastructures, the growing importance of new business applications, and the continued value of legacy systems. It’s a formidable challenge to ensure rapid, reliable, relevant information exchange in an IT environment encompassing both mainframes and next-generation, Internet-based systems.
Often, the problem boils down to communication, or lack of it. Different systems speak different languages. Mainframes pose a particular challenge since they continue to serve as the mainstay of large businesses but support applications that communicate using what some might view as the equivalent of Latin.
Historically, organizations have had limited options to integrate mainframes with other disparate systems and bridge the communications gap. Traditional screen scraping has served as a popular method for integrating 3270-based applications. By far the least popular solution has been to rewrite existing mainframe systems for new functionality. This is prohibitively expensive and doesn’t guarantee new functionality or an acceptable ROI.
Mainframe Web Services, which use open standards to enable Web-based applications to interact with one another, may be the most promising integration solution. Its Service-Oriented Architecture (SOA) provides universal connectivity regardless of programming language, platform, and operating system.
But not all mainframe Web Services are created equal.
Underneath It All
Mainframe Web Services aim to combine existing applications to deliver new services (often called composite mainframe services) that can perform business processes beyond those the individual applications were originally designed to perform. Composite mainframe services typically combine many different mainframe transactions and data sources into one definition. Mainframe Web Services let you expose these composite mainframe services as Web Services Description Language (WSDL) for use by Web Service clients. WSDL describes these services so other Web Services know how they must be accessed, what input is required, and what output is expected.
You can design these composite services using two different approaches. In a bottom-up approach, an adapter runs on a host system and offers connectivity to underlying mainframe systems via an interface. This interface is actually a wrapper containing an entire transaction or data source, providing a one-to-one mapping of all the wrapped data to a Web Service interface.
However, while all the data is exposed to the client, the ability to combine the various components into a composite service is relegated to an off-host system, typically an application server running on a mid-tier platform. Because the application server must coordinate all the data and control the flow of data among individual Web Services, it becomes a performance bottleneck, especially as the Web Service generates data the composite service doesn’t need. Since all data is transferred to the application server before irrelevant data is sifted out and discarded, network traffic increases, too.