Today, more than 30 billion transactions and approximately 75 percent of the world’s business data are processed daily on mainframes worldwide. Developers have further strengthened legacy dependence by continuously enhancing these systems with a high level of business customization.
So-called legacy applications on mainframes still deliver significant value. Although business requirements create a need to modernize the application, it isn’t practical to move data and processes to a new platform, especially one that doesn’t ensure the same degree of speed, stability, and reliability as the mainframe.
Developers haven’t been able to modernize the applications running on System z because these applications are still based on the old, monolithic design where the presentation, business, and data access codes aren’t separated. While the mainframe application is definitely secure, resilient and reliable, previous releases have had limited integration capability due to bad application design and the inability to support a rich Graphical User Interface (GUI). In today’s business environment, with frequent acquisitions and mergers, this makes it difficult for legacy mainframe applications to participate in IT consolidations. This creates a situation where business functions and data present in mainframe applications aren’t available to other businesses. This causes redundant functionality in the IT system and increased cost of maintenance due to the introduction of new applications that could have been avoided by reusing existing mainframe application services.
Legacy code has evolved without any defined strategy, which means it’s complex, redundant, and expensive to maintain. To address these problems, legacy application integration is essential. Here, we’ll outline how you can use mashups and Web 2.0 concepts to successfully integrate your mainframe-based legacy applications.
Conventional Integration Isn’t Sufficient
There are four predominant techniques used to integrate a mainframe-based CICS application with other platform applications:
- CICS Single Object Access Protocol (SOAP) is the most popular method and is an open, standards-based connectivity solution.
- CICS Transaction Gateway (CTG) is used when integrating a mainframe with a Java technology-based platform.
- CICS Web Support (CWS): CICS Transaction Server (CICS TS) on the mainframe provides CWS, where the mainframe acts as an HTTP server and an HTTP client.
- The CICS MQ Bridge provides both asynchronous and synchronous connectivity between mainframe CICS and other platforms such as Java and .NET. It supports XML data type. CICS MQ bridge comes in two flavors: the 3270 bridge, which integrates the terminal-oriented CICS applications, and the Distributed Program Links (DPL) bridge, which integrates the COMMAREA-oriented application.
Enterprises can leverage any of these methods alone or in combination to address their integration needs for legacy applications. However, these conventional methods of legacy integration aren’t sufficient to meet the growing needs of IT. Most conventional integration methods use non-open-standard protocols. The connection/integration breaks when there’s a change either on the host or on the interface. Non-open-standard protocols aren’t adaptable and extensible to a changing environment and future needs in a Business-to-Business (B2B) collaboration. The point-to-point connections increase integration complexity when the number of applications increases. Sometimes, specific vendor product dependencies make the integration inflexible. We need to go beyond these traditional integration methods and look to emerging trends such as Web 2.0.
Integration, as compared to other modernization techniques, requires a minimal change in hardware, software, and development effort. There are tools available to automate the development processes.
The emerging trends in legacy application integration are Service-Oriented Architecture (SOA), Enterprise Service Bus (ESB), and, most recently, Web 2.0. Web 2.0 uses open-standard connectivity based on Real Simple Syndication (RSS), Representational State Transfer (REST), and Atom. It uses SOA as the backbone for interconnectivity, so there’s no scope-of-integration breakage like there is with a point-to-point connection. Because of the open-standard connectivity, Web 2.0-based integration is adaptable to a changing environment and isn’t locked in to a specific vendor. The integration is well-managed even if the number of participating applications increases.