Service-Oriented Architecture

Ever striving for competitive advantage, organizations frequently turn to information technology. This quest - and the numerous technologies and architectural approaches adopted to maximize the value of the information captured in IT assets - has resulted in a collection of frequently incompatible systems and technologies. Organizations find themselves with an accidental IT architecture that limits organizational communication and effectiveness and that should be integrated into a cohesive vision for IT to deliver maximum value to the organization.

Successful implementations of the latest approach for integrating the enterprise, Service Oriented Architecture (SOA), are characterized by high degrees of service sharing (that is, driving the maximum number of consumers to a given service). The higher the degree of service sharing across projects, departments, and applications, the greater the maximization of value to the organization. Shared services transform the business of IT, enabling IT to: decrease time-to-availability; increase business agility and customer responsiveness; reduce business risk; reduce organizational complexity; and change IT cost structures. However, effectively sharing services on a large scale isn't without challenges such as platform diversity, geographic dispersion, and policy inconsistency that must be considered when implementing the SOA.

The Business Case for Integration
Every commercial enterprise is built to create and market a particular product or service. To be successful in these endeavors, enterprises have turned to information technology (IT) to (i) facilitate efficient information exchange between and among multiple internal and external contact points, and (ii) automate repeatable business processes throughout the enterprise. However, IT has changed over time, evolving through architectural approaches (including mainframe computing, client/server computing, Enterprise Resource Planning (ERP), etc.), each of which was adopted as the best practice of its day. This has resulted in an unplanned "hodgepodge" of IT assets across the enterprise. The IT architecture in place at most enterprises is best described as "accidental" - a heterogeneous collection of frequently incompatible systems and technologies - limiting organizational communication and effectiveness. For IT to deliver maximum value to the enterprise, these technologies/products should be integrated into a cohesive vision.

The benefits that arise from the integration of diverse systems are not merely conceptual - many real-world business requirements can best be addressed through such integration. In a thought piece devoted to demonstrating the tangible business benefits of integration, Gartner Inc. highlighted the following needs that can be addressed most efficiently via the integration of existing systems:

• Regulatory compliance, such as Basel II or Sarbanes-Oxley
• Improved business-to-business collaboration
• Mergers and acquisitions
• Deploying new packaged applications
• A single view of information and improved customer visibility
• Implementing self-service portals and customer relationship management
• Improved data and product quality

The Business Case for SOA
Just as the prevailing application paradigm has changed over time, so too have the technologies used to integrate disparate systems. Today's Service Oriented Architecture (SOA) approach is a relatively recent style of computing that allows organizations to make better use of their existing IT assets by facilitating the real-time integration of data and business logic housed in diverse systems. It also provides a foundation for the development of future applications that are constructed from the start with distributed computing and seamless interoperability in mind. If properly implemented, SOA-based solutions enable seamless connectivity and the free exchange of information, helping the organization achieve its business goals better.

Enterprises often approach SOA in a timid fashion that limits its potential impact. This occurs despite the potential strategic benefits that stem from SOA adoption (such as increased business agility and improved organizational consistency). This need not be the case - SOA can yield benefits even if adopted in a low-risk, incremental fashion - as long as care is taken to ensure adherence to long-term architectural strategy. By embracing SOA in this manner, organizations can achieve significant productivity gains.

To reap the full advantages of an SOA-based approach, organizations should consider a dual-focus strategy: concentrating on immediate SOA-based projects with tangible business benefits while keeping an eye on strategic enterprise-wide goals. By addressing both short- and long-term objectives, enterprises can focus on specific near-term business challenges and enable sustained competitive advantage through organizational efficiency and the realization of new business opportunities.

SOA Benefits Include:

• Enforced consistency of business and IT behavior on expansive enterprises
• Better cost control and increased IT efficiency
• Preservation of existing IT investments

The Importance of Service Sharing
Successful SOA implementations are characterized by high degrees of service sharing (i.e., driving the maximum number of consumers to a given service). All the technical characteristics of SOA (loose coupling, standards adherence, location-independent, etc.) are designed to maximize service sharing; all business benefits derived from SOA (reduced duplication of efforts and personnel, decreased time-to-production for new processes and applications, increased business agility and customer responsiveness, reduced business risk, and reduced organizational complexity) arise from service sharing.

Business Services, Software Services, and SOA
SOA is essentially an architectural approach to IT that supports the inter-communication of multiple shared software services, each in turn enabling a business service.

A business service is a function that is offered to the organization, and shared throughout the enterprise. While some services are specific to the nature of a particular organization's operation, others are familiar to all. Human resources, finance, sales and marketing, and legal processes are all examples of common, shared business services that are familiar to all organizations.

A software service is a software representation of a business service that is self-contained, and doesn't depend on the context or state of other services. For example, a common software service might be a software component that tracks the vacation time taken by employees. When implemented properly, this vacation service will operate independently of other services and communicate with multiple symbiotic services as conditions require.

Continuing with the example of a vacation service, suppose an employee applied for a week of vacation. The vacation service would determine if there was sufficient accrued vacation to cover the time off requested. If the vacation service determined that the requisite number of hours hadn't been accrued by the employee, the vacation service could then communicate with a payroll service that in turn would deduct the appropriate hours of pay from the employee's paycheck.

It 's important to note that the SOA approach differs significantly from traditional enterprise application software, where each business process was manifested as a single monolithic entity. If such vacation-tracking capabilities existed in a monolithic application, it would exist solely for the use of that monolithic application, unavailable for access throughout the enterprise.

Service Sharing versus Reuse
There is a subtle, but important, distinction between sharing services across an organization and reusing them. Sharing is focused on driving multiple users to use, or consume, a particular service (i.e., a single instance of a service). Reuse involves propagating, or "cloning," copies of a given service across an enterprise.

The ultimate value of SOA stems from service sharing. By encouraging and enabling the maximum number of consumers of a service, like our vacation service described above, organizations can harvest the maximum value from the service. Reusing services also transfers a service's functionality across an organization, but it does so in a way that is inefficient, inflexible, and lacks consistency over time. If a business process changes, a shared service will immediately propagate the change across the organization, while each instance of a reused service must be modified independently. Again, maximum service sharing drives the success of any SOA-based solution.

Benefits of Service Sharing
IT organizations have traditionally implemented application architectures that were monolithic in nature. Traditional ERP, human resources, and CRM applications are all examples of monolithic applications. These systems don't allow for high degrees of interoperability and information exchange, and are too rigid to respond adequately to changing business conditions. Business processes have therefore been defined by the prevailing application infrastructure as opposed to the business needs driving IT design and implementation.

The advent of SOA promises to reverse this sub-optimal approach by modeling and modifying applications and IT infrastructure according to business concerns. The concept of sharing common services is core to this new model since it provides a focal point for encapsulating business processes and required modifications driven by changing conditions. The flexibility of SOAs will also yield long-term cost efficiencies that were previously unattainable. According to "Loosely Coupled," a newsletter focused on SOA news and trends, "Once the SOA begins to take shape, future projects will cost less because they can take advantage of the emerging shared-services infrastructure."

SOA and sharing services will also have a positive impact on how IT organizations operate. Shared services transform the business of IT, enabling IT to:

• Decrease time-to-availability by quickly composing new applications from existing software assets
• Increase business agility and customer responsiveness by responding quickly to changing conditions and demands on an organization
• Reduce business risk by implementing uniform policies, such as those focused on security, across services
• Reduce organizational complexity by focusing on fewer systems and eliminating redundancy in the organization
• Change IT cost structures by reducing maintenance costs through the use of fewer larger systems