Service Mediation Challenges Service-Oriented Architecture

1-2 Oracle Fusion Middleware Concepts and Architecture for Oracle Service Bus

1.1.1 Service-Oriented Architecture

Service-Oriented Architecture SOA has emerged as the leading IT agenda for infrastructure reformation, to optimize service delivery and ensure efficient business process management. Part of the paradigm shift of SOA are fundamental changes in the way IT infrastructure is designed—moving away from an application infrastructure to a converged service infrastructure. Service-Oriented Architecture enables discrete functions contained in enterprise applications to be organized as layers of interoperable, standards-based shared services that can be combined and reused in composite applications and processes. In addition, this architectural approach also allows the incorporation of services offered by external service providers into the enterprise IT architecture. As a result, enterprises are able to unlock key business information in disparate silos, in a cost-effective manner. By organizing enterprise IT around services instead of around applications, SOA helps companies achieve faster time-to-service and respond more flexibly to fast-paced changes in business requirements. In recent years, many enterprises have evolved from exploring pilot projects using ad-hoc adoption of SOA and expanded to a defined repeatable approach for optimized enterprise-wide SOA deployments. All layers of an IT SOA architecture have become service-enabled and comprise of presentation services, business processes, business services, data services, and shared services. Figure 1–1 SOA Conceptual Architecture

1.1.1.1 Service Mediation Challenges

A major challenge for SOA initiatives is attributed to the inherently heterogeneous multi-vendor IT landscape in many enterprises, and the resultant individual silos of business information. Rather than incur the cost and complexity of replacing disparate Introduction 1-3 components of legacy infrastructure, enterprises often choose to extend existing business applications as services for use in other business processes and applications. The influx of Web service interfaces to functionality within existing packaged applications, often introduces services that do not adhere to established service and compliance guidelines. This is especially true if the services are published from core enterprise systems such as CRMs, Data Warehouses, and ERPs. In the absence of robust and comprehensive service infrastructure solutions, developers have used a variety of middleware technologies to support program-to-program communication, such as object request brokers ORBs, message-oriented middleware MOM, remote procedure calls RPC. More recently, IT infrastructure developers hard-coded complex integration logic as point-to-point connections to web services, in order to integrate disparate applications and processes. This inevitably resulted in complex service sprawls within enterprise IT environments. The following figure illustrates a typical static service integration scenario. Figure 1–2 Service Sprawl Challenge The following are other service related challenges attributed to heterogeneous IT architectures: ■ Tightly-coupled business services integration due to complex and rigid hard-wired connections ■ Difficulty managing deployed services due to disparate protocols and applications involved ■ High total cost of ownership for the enterprise ■ Impaired ability to reuse services ■ Inherent replication of transport, transformation, security, and routing details ■ Exponential redevelopment and redeployment efforts when service end-point interfaces change 1-4 Oracle Fusion Middleware Concepts and Architecture for Oracle Service Bus ■ Inevitable service disruption that significantly impact service consumers Enterprise architects and web service modelers with goals to streamline IT infrastructure now require enterprise service capabilities that address the following IT needs: ■ Simplify access and updates to data residing in different sources ■ Reuse services developed across the enterprise and effectively manage their life cycle ■ Provide dynamic configuration of complex integration logic and message routing behavior ■ Enable run-time configuration capabilities into the service infrastructure ■ Ensure consistent use of the enterprise services ■ Ensure enterprise services are secure and comply with IT policies ■ Monitor and audit service usage and manage system outages

1.1.1.2 Composite Applications and Service Layering