A design framework for Internet-scale event observation and notification
David S. Rosenblum, Alexander L. Wolf · ACM SIGSOFT Software Engineering Notes · 1997
There is increasing interest in having software systems execute and interoperate over the Internet.Execution and interoperation at this scale imply a degree of loose coupling and heterogeneity among the components from which such systems will be built.One common architectural style for distributed; loosely-coupled, heterogeneous software systems is a structure based on event generation, observation and notification.The technology to support this approach is well-developed for local area networks, but it is illsuited to networks on the scale of the Internet.Hence, new technologies are needed to support the construction of large-scale, event-based software systems for the Internet.We have begun to design a new facility for event observation and notification that better serves the needs of Internet-scale applications.In this paper we present results from our first step in this design process, in which we defined a framework that captures many of the relevant design dimensions.Our framework comprises seven models-an object model, an event model, a naming model, an observation model, a time model, a notification model, and a resource model.The paper discusses each of these models in detail and illustrates them using an example involving an update to a Web page.The paper also evaluates three existing technologies with respect to the seven models.