Comparison of Two Middleware Data Dissemination Services in a Wide-Area Distributed System

This paper provides an experimental comparison of two middleware data dissemination services: a distributed object-based service, and a message-based service. This paper compares these two services in the context of a common application: a wide-area network collaboratory, namely the Upper Atmospheric Research Collaboratory (UARC). UARCis an example of an application that reliably-streams data from a set of suppliers to a set of receivers. This comparison highlights the tradeoffs between ease of implementation and performance for a data streaming middleware service. By relying on a rigid language primitive, namely remote method invocation, the object-based dissemination service gave up the control over its transport policies. In contrast, the lower-level socket-based service was specifically constructed to provide a flexible interface to its applications. This flexibility allowed the middleware to better support data delivery t o a heterogeneous set of receivers. This is important in a wide-area distributed system where hosts are connected together over a broad spectrum of network links. This paper provides a concrete example of the effects of high-level design choices an the implementation of a wide-area distributed system’s communication middleware.