Chapter 2. Overview of SOA Integration

Today, there is an increasing drive for organizations to move away from monolithic, static applications to Service Oriented Architecture (SOA). SOA promises to deliver services which are agile, cost-effective, and future-proof. We work with many Fortune 500 companies with legacy applications. Almost all of them have these monolithic systems at the core. What's interesting is that our discussions around new application development initiatives encompasses the notion of services, agility, and portability. We have never gone into an IT planning session with a CIO for the development of linear applications that are not standards-based and do not integrate well with the existing systems. So, the elephant in the room is what to do with these legacy applications. What does SOA mean for organizations that have applications that are years, if not decades old, which are very costly to change and are maintained with a dwindling workforce? These are issues that every IT manager has to deal with. The simple fact is that these systems are at the heart of banking, transportation, and manufacturing sectors around the world. We maintain in the following chapters that there is a methodical way to open these valuable core processing to the future. Organizations do not have to throw the baby out with the bath water when it comes to new initiatives. In the following chapters, we will explore ways to open up our legacy infrastructure. These can enable the integration and extension of the mainframe and even provide a foundation for a full migration, if the business requires it.

It is observed that the term SOA has been used, or I should say, overused, so much in the industry today that it has lost its currency with decision makers. Before we dive into this chapter and examine the drivers for modernization to an SOA architecture, let's define what SOA means in terms of legacy mainframe environment and legacy modernization. Think of SOA as a framework for building applications, rather than a specific set of technologies or protocols. SOA is just a way of providing computing resources by exposing discrete business processes via a standard way for use by consumers. As we had mentioned, it is more than a set of protocols and technologies like SOAP and WSDL or Java/RMI; think of it as a blueprint for building applications. Web services may be one of the ways to implement this framework. Other technologies which can be leveraged to employ an SOA architecture include, Business Activity Monitoring (BAM), Business Process Execution Language (BPEL), Enterprise Service Bus (ESB), and Business Process Management (BPM) engines. Technically, FTP is an SOA interface!

InChapter 3, we will take a deeper dive into the practical application of Legacy Integration strategies utilizing the concept of Enterprise Information Integration (EII) and Enterprise Application Integration (EAI). Using EII/EAI, we can address data and process centric strategies respectively on the legacy platform. To prepare us for a deeper dive into those technologies, let's take some time to cover some more high-level SOA concepts with respect to legacy modernization.