Expressiveness refers to the ability of the event notification service to provide a powerful data model with which to capture information about events, to express filters and patterns on notifications of interest, and to use that data model as the basis for optimizing notification delivery. In terms of scalability, we are referring not simply to the number of event generators, the number of event notifications, and the number of notification recipients, but also to the need to discard many of the assumptionsmade for local-area networks, such as low latency, abundant bandwidth, homogeneous platforms, continuous and reliable connectivity, and centralized control. We recognize that there are other important attributes of an.
