Semantic Distributed Messaging Middleware

Messaging middleware provides asynchronous communication between services in distributed environments. However, security, reliability and performance issues compel such middleware to be distributed, and distribution throws up its own problems such as identifying messaging channels which could then be subscribed to. In particular, interested parties need to identify channels defined in remote locations while not knowing details of how they are defined. A common vocabulary using semantic descriptions offers a solution to this problem. In this paper, we describe the design and implementation of federated messaging middleware using semantic description of channels.

The myGrid Notification Service

The notification service is the part of myGrid that enables asynchronous delivery of messages between distributed components. It includes features such as topic-based publish-subscribe messaging, push/pull models, asynchronous delivery, persistence, transient and durable subscriptions, durable topics, negotiation of QoS, hierarchical topic structure and federation of services. Some of these features are novel in the area of messaging middleware. A cost evaluation of some of these features indicate that the overhead incurred is justified in terms of compensating benefits gained.