The network layer consists of a heterogeneous set of distributed computing and network resources, which are virtualized by a distributed content-based publish/subscribe routing layer. The publish/subscribe overlay exposes a set of communication abstractions including publish/subscribe and point-to-point interfaces. Using these interfaces, a distributed workflow execution engine is deployed, and finally various management and monitoring capabilities are provided to deploy, control or observe the various layers in the system.
A rich event mangement framework allows each layer in the architecture to report detailed information about its characteristics and behaviour. This data from across the layers can be filtered and correlated using a powerful subscription language in a flexible and efficient manner. The data from the event management framework is used both internally by the system to observe and optimize itself, and to report statistics externally to applications and users.