Service-oriented computing (SOC) promotes the idea of assembling application components into a network of loosely coupled services to create flexible, dynamic business processes and agile applications that span organizations and computing platforms. SOC uses services to support the development of rapid, low-cost, interoperable, evolvable, and massively distributed applications. Services are autonomous, platform-independent entities that can be described, published, discovered, and loosely coupled in novel ways. They perform functions ranging from answering simple requests to executing sophisticated business processes. Services reflect a "service-oriented" approach to programming, allowing organizations to expose their core competencies programmatically over the Internet or various networks using standard XML-based languages and protocols. Web services are currently the most promising SOC-based technology. They use the Internet as the communication medium and open Internet-based standards, including SOAP, WSDL, and BPEL4WS. SOC enables developers to dynamically grow application portfolios more quickly by creating compound solutions that use internal organizational software assets and combining these solutions with external components. The SOC research road map introduces an extended SOA that separates functionality into three planes: service foundations, service composition, and service management and monitoring. The perpendicular axis indicates service characteristics that cut across all three planes, including semantics, non-functional service properties, and quality of service (QoS). QoS encompasses important functional and nonfunctional attributes such as performance metrics, security attributes, transactional integrity, reliability, scalability, and availability. The SOC research road map also defines several roles, including service requester, provider, aggregator, and operator. Service foundations consist of a service-oriented middleware backbone that realizes the runtime SOA infrastructure. This infrastructure connects heterogeneous components and systems and provides multiple-channel access to services over various networks. The state of the art in SOC includes the enterprise service bus (ESB), which enables efficient integration of numerous different application components. The ESB is an open-standards-based message backbone designed to enable the implementation, deployment, and management of SOA-based solutions. It supports service, message, and event-based interactions with appropriate service levels and manageability. Research challenges in SOC include dynamically reconfigurable runtime architectures, end-to-end security solutions, infrastructure support for data and process integration, semantically enhanced service discovery, and QoS-aware service compositions. Additionally, challenges in service composition include ensuring that service compositions understand and respect one another's policies, performance levels, security requirements, and service-level agreement (SLA) stipulations. Service management and monitoring involve assessing the health of systems that implement Web services and the status and behavior patterns of loosely coupled applications. Service monitoring involves monitoring events or information produced by the services and processes, monitoring instances of business processes, and viewing process-instance statistics. Service design and development involve engineering service applications, flexible gap-analysis techniques, service versioning and adaptivity, and service governance. SOC is a vast and complex subject that requires integrating many technologies in an intricate manner. By focusing on the inherently related themes of service foundations, service composition, serviceService-oriented computing (SOC) promotes the idea of assembling application components into a network of loosely coupled services to create flexible, dynamic business processes and agile applications that span organizations and computing platforms. SOC uses services to support the development of rapid, low-cost, interoperable, evolvable, and massively distributed applications. Services are autonomous, platform-independent entities that can be described, published, discovered, and loosely coupled in novel ways. They perform functions ranging from answering simple requests to executing sophisticated business processes. Services reflect a "service-oriented" approach to programming, allowing organizations to expose their core competencies programmatically over the Internet or various networks using standard XML-based languages and protocols. Web services are currently the most promising SOC-based technology. They use the Internet as the communication medium and open Internet-based standards, including SOAP, WSDL, and BPEL4WS. SOC enables developers to dynamically grow application portfolios more quickly by creating compound solutions that use internal organizational software assets and combining these solutions with external components. The SOC research road map introduces an extended SOA that separates functionality into three planes: service foundations, service composition, and service management and monitoring. The perpendicular axis indicates service characteristics that cut across all three planes, including semantics, non-functional service properties, and quality of service (QoS). QoS encompasses important functional and nonfunctional attributes such as performance metrics, security attributes, transactional integrity, reliability, scalability, and availability. The SOC research road map also defines several roles, including service requester, provider, aggregator, and operator. Service foundations consist of a service-oriented middleware backbone that realizes the runtime SOA infrastructure. This infrastructure connects heterogeneous components and systems and provides multiple-channel access to services over various networks. The state of the art in SOC includes the enterprise service bus (ESB), which enables efficient integration of numerous different application components. The ESB is an open-standards-based message backbone designed to enable the implementation, deployment, and management of SOA-based solutions. It supports service, message, and event-based interactions with appropriate service levels and manageability. Research challenges in SOC include dynamically reconfigurable runtime architectures, end-to-end security solutions, infrastructure support for data and process integration, semantically enhanced service discovery, and QoS-aware service compositions. Additionally, challenges in service composition include ensuring that service compositions understand and respect one another's policies, performance levels, security requirements, and service-level agreement (SLA) stipulations. Service management and monitoring involve assessing the health of systems that implement Web services and the status and behavior patterns of loosely coupled applications. Service monitoring involves monitoring events or information produced by the services and processes, monitoring instances of business processes, and viewing process-instance statistics. Service design and development involve engineering service applications, flexible gap-analysis techniques, service versioning and adaptivity, and service governance. SOC is a vast and complex subject that requires integrating many technologies in an intricate manner. By focusing on the inherently related themes of service foundations, service composition, service