Abstract
Distributed systems have gained alot of acceptance, especially with the growth and popularity of the Internet. The Object Management Group (OMG) is a consortium established to create standards for distributed systems. In 1990, the OMG created the Common Object Request Broker Architecture (CORBA) as a standard architecture for distributed computing environments. CORBA is a well accepted distributed system integration framework based on object-oriented methodologies. CORBA allows the integration of heterogeneous hardware and software components to interact with each other using a common "information bus" called the Object Request Broker (ORB). The ORB is the common medium through which objects (client and server) located remotely from each other communicate. Furthermore, CORBA is an architecture that allows systems to be scalable, portable and interoperable through CORBA's different communication components. However, CORBA introduces a significant amount of communication overhead.

This thesis analyzes and quantifies what aspects of CORBA generate the communication overhead. First, an analysis of the CORBA communication architecture is presented. Second, a communication classification is developed for further analysis of the different communication components of CORBA. Third, a mathematical model is developed for quantifying the communication costs in CORBA under different communication scenarios. Fourth, a detailed analysis of the marshalling process is developed and finally, a benchmark program is developed for supporting and confirming the prior analysis. This thesis concludes that there is a significant communication overhead in CORBA systems.