1 Introduction

This section discusses the current focus on service-driven IT strategies, key business drivers for Service-Oriented Architecture (SOA) initiatives and the strategic significance of an Enterprise Service Bus (ESB) component. It provides a conceptual overview of Oracle Service Bus infrastructure solution and functional capabilities that distinguish it as an SOA success factor. It is intended for management stakeholders responsible for SOA initiatives, integration-focused IT architects, service modelers or designers, and system administrators.

The following topics are included in this section:

Section 1.1, "Service-Oriented IT Trends"
Section 1.2, "Oracle Product Suite"
Section 1.3, "Oracle Service Bus"

1.1 Service-Oriented IT Trends

In today's highly competitive global market, businesses operate in a very liquid environment in which information is the most strategic asset. Responding rapidly to changes in competition, market dynamics, and regulatory mandates, with timely information, is critical for the effective functioning and overall success of businesses. To meet rapidly changing market demands, businesses have become increasingly service-driven, both in the ways they interact with customers and partners, and in how they design and build their IT infrastructure.

As businesses strive to deliver ROI through increased agility and responsiveness, they depend on enterprise IT groups to find new and cost effective means to deliver new services and to promote the free flow of information and business processes within the organization. The following business drivers have made service-oriented IT architectures an economic reality in today's enterprise:

Industry adoption of Web services to rapidly expose and enable new and legacy services
Necessity to build system-centric processes spanning applications and users
Necessity to quickly expose processes as services
Execute mission-critical processes securely and consistently, with transactional integrity
Develop fine-grained integrated application and process control
Deliver high performance execution for straight-through processing

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

Description of "Figure 1-1 SOA Conceptual Architecture"

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 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

Description of "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
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 lifecycle
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

1.1.1.1 Composite Applications and Service Layering

In an SOA initiative, composition is an integral part of achieving business flexibility through the ability to leverage existing assets in higher-order functions.Within a mature SOA environment, complete business applications are composed using existing services to quickly meet the business needs. Flexibility in the service provisioning process, is achieved by avoiding coding logic in service implementations.

Many organizations develop services at very granular levels and the proliferation of many small specific services are difficult to compose into broader logical services. Layering of Services is as a way of breaking out of the limitations of monolithic applications and shortening development, release and test cycles. By defining a layered approach to service definition and construction, the service infrastructure team can achieve the right mix of granular and course-grained services required to meet their current and future business demands.

Service Layers typically comprise of the following services:

Physical Services: that may represent functions that retrieve data in its raw form
Canonical Services: that may define a standard view of information for the organization, leveraging industry-standard formats and supporting a very wide data footprint
Logical Services: that provide a more client-specific granular view of information, generated at compile time using highly-optimized queries
Application Services: that are consumed directly by applications in a line-of-business dependent fashion and may be exposed through presentation services

1.1.2 Service Bus Component of SOA

The core of SOA success depends on an Enterprise Service Bus (ESB) that supports dynamic synergy and alignment of business process interactions, continual evolution of existing services and rapid addition of new ones. To realize the benefits of SOA, it is imperative that IT organizations include a robust and intelligent service intermediary that provides a layer of abstraction to mask the complexities of service integration in heterogeneous IT environments, typical in today's enterprises. While an intermediary layer of abstraction previously implied a platform for customizing enterprise applications, today it implies toolkits for service customization and scalable infrastructures that support loosely coupled service interactions with a focus on service mediation.

Figure 1-3 Enterprise Service Bus

Description of "Figure 1-3 Enterprise Service Bus"

ESBs have been instrumental in the evolution of integrated middleware infrastructure technology by combining features from previous technologies with new services, such as message validation, transformation, content-based routing, security and load balancing. ESBs use industry standards for most of the services they provide, thus facilitating cross-platform interoperability and becoming the logical choice for companies looking to implement SOA.

An ESB provides an efficient way to build and deploy enterprise SOA. ESB is a concept that has gained the attention of architects and developers, as it provides an effective approach to solving common SOA hurdles associated with service orchestration, application data synchronization, and business activity monitoring. In its most basic form, an ESB offers the following key features:

Web services: support for SOAP, WSDL and UDDI, as well as emerging standards such as WS-Reliable Messaging and WS-Security
Messaging: asynchronous store-and-forward delivery with multiple qualities of service
Data transformation: XML to XML
Content-based routing: publish and subscribe routing across multiple types of sources and destinations
Platform-neutral: connect to any technology in the enterprise, e.g. Java, .Net, mainframes, and databases

Figure 1-4 ESB Architecture

Description of "Figure 1-4 ESB Architecture"

A robust SOA suite offers:

Adapters, to enable connectivity into packaged and custom enterprise applications, as well as leading technologies.
Distributed query engine, for easily enabling the creation of data services out of heterogeneous data sources
Service orchestration engine, for both long-running (stateful) and short-running (stateless) processes
Application development tools, to enable the rapid creation of user-facing applications
Presentation services, to enable the creation of personalized portals that aggregate services from multiple sources

Using ESBs offers greater flexibility for enterprises to connect heterogeneous resources, by eliminating the need for brittle high-maintenance point-to-point connections. Adding an ESB intermediary between service consumers and service providers, shields them from the implementation details of underlying service end-point interfaces, reducing or eliminating the redevelopment and redeployment impacts at the service-consumer level.

Best in class enterprises have achieved SOA success by harnessing high-speed enterprise-ready ESB intermediaries that strategically integrate service mediation capabilities and business process management functionality. Recognizing the significance of operational service management as a critical SOA success factor, they have implemented solutions that provide enterprise-class service scalability, reliability, customization and security. By adopting such solutions built specifically for management and governance of an SOA service lifecycle, these enterprises have obtained the following business benefits:

Minimized costs by accelerating SOA deployment initiatives
Ensured customer satisfaction by assurance of continuous service availability
Insulated service consumers to changes in service infrastructure by virtualizing service end points
Maximized ROI by leveraging shared services infrastructure and using consistent modeling methodologies
Reduced integration burden by simplifying service interactions
Improved effectiveness of SOA initiatives through accurate run-time governance of shared services
Justification of SOA spending by inventory and tracking of run-time services
Accurate cost benefit decisions by measuring the benefit or cost avoidance obtained through SOA

Figure 1-5 Enterprise Integration for SOA

Description of "Figure 1-5 Enterprise Integration for SOA"

1.2 Oracle Product Suite

Oracle offers the first service-infrastructure product family built from the ground up for Service-Oriented Architectures, giving IT a unified set of products to successfully deploy an SOA across their organization and achieve better business agility and IT efficiency.

Figure 1-6 Oracle Service Bus Shared Services Product Architecture

Description of "Figure 1-6 Oracle Service Bus Shared Services Product Architecture"

The following product lines are available within the Oracle product family:

Oracle User Interaction: an integrated product line used to create a variety of interactive solutions that leverage the service infrastructure, including portals and composite applications.
Oracle Business Process Management: a product line that includes software that automates, executes, and monitors the entire lifecycle of a business process.
Oracle Data Service Integrator: a product line which enables data services that deliver unified, real-time views of data from disparate sources across the enterprise.

1.3 Oracle Service Bus

Oracle Service Bus is a proven market-leading Enterprise Service Bus (ESB) built from the ground up for SOA lifecycle management that provides foundation capabilities for service discovery and intermediation, rapid service provisioning and deployment, and governance.

This service-infrastructure software adheres to the SOA principles of building coarse grained, loosely coupled, and standards-based services, creating a "neutral container" in which business functions may connect service consumers and back-end business services, regardless of underlying infrastructure.The following figure illustrates the role of Oracle Service Bus as a service intermediary in an enterprise IT SOA landscape:

Figure 1-7 Oracle Service Bus Intermediary

Description of "Figure 1-7 Oracle Service Bus Intermediary"

Built to meet exacting standards for reliability, availability, scalability, and performance, Oracle Service Bus uniquely combines the integration capabilities of an Enterprise Service Bus with operational service management, into a single enterprise-class software product, with a layered functional architecture.

Figure 1-8 Oracle Service Bus Functional Features

Description of "Figure 1-8 Oracle Service Bus Functional Features"

The functional features of Oracle Service Bus can be categorized into the following functional layers:

Messaging Layer: that reliably connects any service by leveraging standards web service transports, traditional messaging protocols and configuration of enterprise-specific custom transports. For more information, see Section 1.3.3.1, "Adaptive Service Messaging Layer".
Security Layer: a rapid service configuration and integration environment that abstracts policies associated with routing rules, security, and service end-point access. For more information, see Section 1.3.3.2, "Optimized Pluggable Security Layer".
Composition Layer: a meta-data driven feature-rich configuration interface for service discovery and validation capabilities for automatic import and synchronization of services with UDDI registries, allows message flow modeling, transformations, third-party service callouts and a test console. For more information, see Section 1.3.3.3, "Rich Service Composition Layer".
Management Layer: a service management environment that includes dynamic service and policy configuration, centralized usage and performance monitoring, and management of services - not just Web services, but also Java, .Net, messaging services, and legacy end points. For more information, see Section 1.3.3.4, "Embedded Service Management Layer".

1.3.1 Significance in an SOA Landscape

Oracle Service Bus is at the heart of Oracle's comprehensive business integration solution and belongs to the Oracle Messaging product line. Oracle Service Bus is primarily targeted for managing different types of services, and providing traditional message brokering across heterogeneous IT environments.

The lightweight, stateless, high-performance architecture of Oracle Service Bus and its converged intelligent message mediation and service lifecycle management capabilities, make it an ideal core component of distributed services networks.

It is designed to fit into the broader IT Service-Oriented Architecture (SOA) landscape as a distributed service management intermediary and can be integrated with other Oracle business process management solutions in distributed heterogeneous deployments.

Figure 1-9 Oracle Service Bus Significance in SOA Architecture

Description of "Figure 1-9 Oracle Service Bus Significance in SOA Architecture"

1.3.1.1 Oracle Service Bus Use Cases

Oracle Service Bus is a powerful lightweight, cost-effective technology that can be used by service developers and architects for the following use cases:

Building an Enterprise-Wide SOA: a backbone that transports and routes messages across an enterprise, for configuring request-and-response message flows between service consumers and service providers
Building reusable atomic services: that facilitate organizational flexibility and promote application integration and data synchronization across multiple applications
Creating composite applications: by rapidly building new applications that access services of existing applications from a shared service catalog, reducing time to market through reuse
Business Activity Monitoring (BAM): enable business users to get access to key performance indicators and act on business alerts, listen for business events flowing through the infrastructure, and orchestrate services in response to these events, using portals that provide a personalized view of enterprise services

1.3.2 Oracle Service Bus and the Service Lifecycle

The lifecycle of a service comprises of the following two phases:

Design phase: in which the service architecture team identifies an organization's business needs and models a number of services and application interfaces to support those needs
Run-time phase: in which the services modeled using the catalog of business needs are used as a road map for service creation and exposed as run-time offerings within the organization

Figure 1-10 Services LifeCycle

Description of "Figure 1-10 Services LifeCycle"

Oracle Service Bus plays an integral part in the service lifecycle run-time phase. It facilitates the following important functions in the services lifecycle:

Promotes logical or conceptual layering of the system - by allowing for design and provisioning layered services during the run-time phase. This ensures run-time flexibility and no loss of agility at provisioning time.
Manages and monitors the flow of messages between consumers and providers
Insulate users and processes from service changes - by abstracting services and removing shared integration logic from service endpoints
Provides service transformation, validation, enrichment and routing - by bridging protocols, message styles, security and data formats
Provides visibility and operational service management - by exposing services for use by consumers

1.3.2.1 Role of Oracle Service Bus in a Service Cycle

A key design philosophy of Oracle Service Bus is the physical separation of management functions from service implementations. As part of an enterprise's messaging fabric, Oracle Service Bus can be used horizontally integrate many applications and systems, spanning service implementations in different departments built by different teams.

As services are created, they are registered and exposed for later consumption by other services or processes. Services can be registered directly with Oracle Service Bus in its local service registry, or imported from an enterprise service registry such as the Oracle Service Registry. After services are registered with Oracle Service Bus, it configures proxy interfaces that define the message flow for communicating with these services.

This flow contains any transformation and security requirements that must be applied, as well as specifications for routing the message to the service. After services are registered with Oracle Service Bus, business processes, such as those created with Oracle WebLogic Integration, can consume these services and orchestrate them to support various business contexts. These orchestrated processes define how the services are used and applied to business requirements and fine-grained business processes. These business processes are then exposed for use by end users through a user interface (UI), which could be a transactional portal such as Oracle WebLogic Portal or a collaborative portal such as Oracle User Interaction.

Oracle Service Bus again steps into the lifecycle to monitor and manage message flow, system health, and availability between service end points. This information may be reported to business and operations analysts who can analyze it for patterns of behavior indicating where improvements should be made. The lifecycle begins again as services evolve over time and new versions are released.

1.3.3 Functional Features and Benefits

The key functional capabilities in the Oracle Service Bus can be classified into the following functional layers:

Section 1.3.3.1, "Adaptive Service Messaging Layer"
Section 1.3.3.2, "Optimized Pluggable Security Layer"
Section 1.3.3.3, "Rich Service Composition Layer"
Section 1.3.3.4, "Embedded Service Management Layer"

1.3.3.1 Adaptive Service Messaging Layer

Oracle Service Bus supports an unprecedented level of heterogeneity and can reliably connect any service by leveraging standards. Existing middleware, applications, and data sources become first-class citizens of SOA initiatives, protecting existing IT investments and enabling IT to connect, mediate, and manage services using heterogeneous end points, formats, and protocols.

Figure 1-11 Adaptive Service Messaging Layer

Description of "Figure 1-11 Adaptive Service Messaging Layer"

Oracle Service Bus works with diverse Web Services transports including the following:

HTTP/SOAP
WS-I, WS-Security, WS-Policy, WS-Addressing
SOAP v1.1 and v1.2
EJB/RMI on WebSphere

Oracle Service Bus includes support accepting SOAP 1.1 messages and converting them to SOAP 1.2 messages when necessary to invoke a SOAP 1.2 business service, and vice versa.

Oracle Service Bus promotes efficient message orchestration by working with traditional messaging protocols and messaging paradigms. For a complete list of supported protocols and communication paradigms, see Chapter 3, "Service Integration", topics Section 3.2, "Oracle Service Bus Resources" and Section 3.1.5, "Messaging Models".

In addition to its industry-leading support for Web services, Oracle Service Bus also provides native connectivity to MQ Series, CICS, .NET, C/C++ applications. It allows creation and configuration of enterprise-specific custom transports using the Custom Transport Software Development Kit (SDK) and native transport for Oracle Data Service Integrator. It provides the ability to create a generic proxy services that can accept any SOAP or XML message, using generic proxy service templates.

Oracle Service Bus supports optimized database queries across the SOA for high performance and reliability, and interoperability with web service integration technologies including .NET, Tibco EMS, IBM MQ, IBM WebSphere, Apache Axis, Cyclone B2B Interchange, and iWay adapters.

For information on Oracle Service Bus interoperability, see "Oracle Fusion Middleware Supported System Configurations" at http://www.oracle.com/technology/software/products/ias/files/fusion_certification.html.

1.3.3.2 Optimized Pluggable Security Layer

Oracle Service Bus ensures service security at all levels. A comprehensive set of components for built-in security give customers significant flexibility and choice. Users can also plug in home-grown or third-party security components. Built-in capabilities allow flexibility in implementation by enabling security at the following levels:

Transport Security - SSL/Basic Auth
Message Security - support for WS-Policy/WS-Security, SAML, UserID/Password, X509, Signing & Encryption, and Custom security credentials
Console Security - support for user Web Single-Sign-On and role based access
Policy - leverages WS-Security and WS-Policy

Figure 1-12 Optimized Pluggable Security Layer

Description of "Figure 1-12 Optimized Pluggable Security Layer"

For more information on Oracle Service Bus security features, see Oracle Fusion Middleware Developer's Guide for Oracle Service Bus.

1.3.3.3 Rich Service Composition Layer

Oracle Service Bus provides a rich environment for service configuration, modeling, discovery and message validation. It also supports message transformations, service callouts to external service providers, and a test browser.

Figure 1-13 Service Composition Layer

Description of "Figure 1-13 Service Composition Layer"

Oracle Service Bus configuration-driven composition environment, with Oracle Service Bus plug-ins for Eclipse and the Oracle Service Bus Console, is designed with a no coding approach, allows message flow modeling using versatile graphical modeling tools. The modeling capabilities allow for configuration of dynamic content-based routing, message validation and exception handling. For more information on dynamic routing, see Chapter 5, "Service Composition", topic Section 5.1, "Dynamic Content-Based Routing".

The composition environment includes a service discovery and validation capabilities for automatic import and synchronization of services with UDDI registries. This functionality allows for validation to ensure service integrity and reconciliation of conflicts before deployment. For more information on UDDI registries, see Chapter 4, "Service Configuration", Section 4.3.1, "UDDI Registry."

Oracle Service Bus supports XML and non-XML transformation of disparate data types shared between source and destination services. Data mappings using XQuery and the eXtensible Stylesheet Language Transformation (XSLT) standard are supported. These can be created externally and imported into Oracle Service Bus, or scripted using XQuery in the Oracle Service Bus Console. Message content reformatting can be performed using XQuery or XSLT or by manipulating message content by adding, removing, or replacing selected elements. For more information on transformations, see Chapter 5, "Service Composition", topic Section 5.3, "Transformations.".

Oracle Service Bus supports dynamic routing through a service callout feature which allows more flexible and sophisticated message flow modeling. Service callouts within message flows can be used to invoke other services registered within Oracle Service Bus and may be Java exit (Plain Old Java Object) or Web Services call-outs. The composition environment also features a test console for tracing and trouble-shooting services. For more information on service callouts, see "Constructing Service Callout Messages" in the Oracle Fusion Middleware Administrator's Guide for Oracle Service Bus.

1.3.3.4 Embedded Service Management Layer

Oracle Service Bus offers embedded service management capabilities that provide optimized governance of all messaging. Its preemptive support ensures that mission-critical business processes continue to serve customer needs, even as business demands, requirements, and workloads change.

Figure 1-14 Oracle Service Bus Embedded Service Management

Description of "Figure 1-14 Oracle Service Bus Embedded Service Management"

Oracle Service Bus Dashboard provides an unified data service interface for all application development and maintenance, service monitoring and management and improved operations support. The dashboard allows for monitoring of fault and performance metrics, viewing of summaries for aggregated ESB. It allows for dynamically defining and managing routing relationships, transformations, and policies. For more information on Dashboards, see Chapter 6, "Service Management", topic Section 6.1.1, "Dashboard".

Oracle Service Bus has built-in optimizations for performance and monitoring, guarantee quality of service through alert monitoring on single node or entire server, and configurable Service Level Agreements (SLAs) for messages. It also supports viewing and managing SLA alerts on operation metrics and message pipelines. For more information on configuring SLAs, see Chapter 6, "Service Management", topic Section 6.1.3, "SLA Enforcement via Alerts".

Oracle Service Bus allows integration of widely adopted out-of-the-box third-party reporting tools as well as custom Enterprise Systems Management frameworks. In addition, it supports open interfaces for operational and deployment customization, JMX monitoring interfaces and SNMP Alerts. For more information on reporting features, see Chapter 6, "Service Management", topic Section 6.2, "Message Reporting".

1.3.3.5 Feature Benefits

The following table summarizes functional features of the Oracle Service Bus and highlights the business requirements addressed by each functionality.

Table 1-1 Oracle Service Bus Features and Benefits

Functionality	Functional Feature	Business Benefit
Message Routing	Configuration-driven intelligent, content-based and identity-based routing	Rapidly respond to business needs by quickly configuring routing rules based on changes to business rules or existing IT systems, without coding
Message Transformation	Dynamic message transformation based on XQuery or XSLT, supporting multiple message formats	Flexibly adapt to evolving SOA and integration project scenarios through the ability to dynamically transform and route services using simple and/or complex routing rules and/or message payloads
Service Registry	Automated or administrator-driven interoperability with UDDI V3 registries for service publishing and reuse	Increase ease of re-use by automatically discovering existing services and exporting new services to the service registry
Service Provisioning	Simplified service provisioning	Increase ease of managing multiple versions of services, simplify and speed deployments by eliminating build-test development cycles
Message Security	Optimized, pluggable, policy-driven transport and message level security	Leverage existing investments in security infrastructure and seamlessly broker between multiple security frameworks
Service End-point Interoperability	Extensibility and expanded service end-point support	Extend solution to accommodate unique IT requirements using infrastructure with certified interoperability with multiple standards, protocols, and vendors
Service Level Agreements	Rules-driven, configurable Service Level Agreement (SLA) enforcement	Gain visibility and control by enabling users to set SLAs based on a number of factors and alerts when the SLAs are not met
Message Transport	Extensible support for heterogeneous transports between service end points including custom transports via the Custom Transport SDK	Provides flexibility to leverage existing investments in disparate systems and/or ensure smooth transition from older to newer systems
Message Brokering	WS-I compliant Intelligent messaging brokering with support for multiple transport types, message formats	Ensure investment protection and leverage existing infrastructure through the ability to orchestrate services from existing IT systems with disparate messaging protocols without needing to change the systems and styles
Service Availability	Proactive infrastructure health and availability monitoring with JMX and SNMP	Maintain health and availability of the SOA through easy configuration of support of performance metrics and SLAs using a built-in, feature-rich dashboard OR 3rd party performance management systems.
Service Monitoring Dashboard	Flexible, graphical, and embedded management and monitoring dashboard	Automatically monitor and manage status of performance metrics and SLAs using a built-in, feature-rich dashboard or 3rd party performance management systems. Proactively take corrective action based on alerts.
Service Deployment	Easy, customizable programmatic or console-driven deployment	Ability to enforce governance and speed deployments