Service Oriented Architecture Overview
Advantages focus on optimized alignment of IT assets with business priorities
”Finally, we can get the technology capabilities we need across the enterprise”
- SOA enables system modernization and agility
- SOA leverages existing IT assets through services
- Optimize alignment of IT investment with business goals
To break up organizational silos, improve interoperability of systems, leverage existing information technology assets, and increase business agility, government agencies and businesses are pursuing Service Oriented Architecture (SOA) to enable the Service Oriented Enterprise.
SOA can be defined as analysis, design, architecture, development, deployment, utilization, governance, and management of information technology (IT) assets as loosely coupled services capable of being used by multiple separate systems in a service-oriented environment. Key characteristics of SOA include: process optimization, service reusability, scalability, and seamless integration.
Service Orientation Principles
SOA provides an approach to building IT systems in which business services are the key organizing principle used to align IT systems with the needs of the enterprise. In contrast, earlier approaches to building IT systems tended to tightly couple system interfaces resulting in systems tied to specific execution environments. There are ten key service orientation principles: standardized service contract, loose coupling of services, service abstraction, reusability, autonomy, statelessness, discoverability, composability, optimization, and service encapsulation. There are four general types of services in SOA:
- Line of Business Services (Capability Services)
- Enterprise Services
- Application Specific Services
- Infrastructure Services (Utility Services)
Key Point:
Loose coupling of services improves information sharing, increases business agility and breaks the cycle of hard to maintain tightly coupled legacy systems.
Additional types of services include: entity services (data services), process services, and integration services.
SOA Lifecycle Phases
There are four phases in the SOA Lifecycle, which is based upon a process centric view:
- Process Modeling
- Process Implementation
- Process Execution and Control
- Process Monitoring
During the Process Modeling Phase, process analysts work with process owners to analyze business processes and define the process model, including activity flow, information flow, actors, roles, business rules, policies, drivers, constraints, and performance measures. Business Process Modeling (BPMN) and Unified Modeling Language (UML) are used to support these activities, and Key Performance Indicators (KPIs) are defined.
During the Process Implementation Phase, developers work with process analysts to implement business processes with development activities that map BPMN process models into an executable representation using Business Process Execution Language (BPEL). Processes are decomposed into services, which are developed or reused, processes are orchestrated, and the presentation layer user interface is developed. Services and processes communicate using an Enterprise Service Bus (ESB), which functions as a common integration layer to connect systems, processes, and services.
During the Process Execution and Control Phase, users execute business processes utilizing the developed system of services and IT assets.
During the Process Monitoring and Optimization Phase, process owners monitor KPIs of the processes using Business Activity Monitoring (BAM). As a result, business issues are analyzed and processes are optimized for increased operational efficiency and business value.
Business Advantages
Key drivers for SOA include the need to align IT assets with business requirements, process optimization, and business agility, which enable an organization to increase operational efficiencies and create new business value. Key business benefits of Service Oriented Architecture include:
- Better alignment of business and IT
- Increased speed to market using modular solutions
- End to end business process support
- Process monitoring, control, and optimization
- Increased operational efficiency
- Leverages IT investment across multiple solutions and projects
Summary
Service Oriented Architecture breaks up silos of information, breaks the cycle of hard-wired brittle systems, increases business agility, and provides a pathway to enablement of the Service Oriented Enterprise. Loose coupling of services improves agility of information sharing and enables process optimization to increase organizational effectiveness.