Unified service-oriented architecture for federated and locally distributed CAMX publish/subscribe middleware

CAMX (computer aided manufacturing using XML) production systems are built on message-oriented middleware frameworks, offering standards-based communication among machines and control software applications. CAMX frameworks implement publish/subscribe of XML messages through an entity called the message broker (MSB), which provides the messaging service using a SOAP interface. A challenge for MSB-based systems is that they must scale to handle large volumes of messaging traffic, characteristic of information-intensive manufacturing systems. This paper firstly tackles this challenge by presenting an architecture for creating locally distributed MSB clusters, which increase the capacity of the framework by distributing the load among several processing units. This centralized approach is complementary to a previously presented architecture for federated message broker nodes. A unified architecture is subsequently presented that enhances federated frameworks by enabling dynamically increasing the capacity of a node by adding new computational resources and forming locally distributed MSB clusters. Service-oriented architecture is used to provide a uniform interface for distributed MSB elements, whether federated or locally distributed. The service-oriented approach is also used to dynamically discover resources and invoke the configuration and messaging services provided by system components.