RMIX: Multiprotocol RMI Framework for Java

Web Service technologies have recently attracted attention as promising vehicles for interoperability in e-commerce and enterprise collaboration. Attempts to leverage Web Services for high performance scientific and distributed computing, however, have encountered performance problems owing to the unsuitability of SOAP (the de facto Web Services wire protocol) for large volume data transfers. Alternative standards are likely to emerge, but currently, many different protocols remain in use. Supporting a scheme to dynamically select from multiple protocols as appropriate to the situation seems to be a sound solution. In the context of distributed computing with Java, RMI is a natural programming paradigm. However, the default RMI implementation is bound to a concrete wire protocol, JRMP, that is neither interoperable nor very efficient. In this paper, we propose a framework than permits the use of multiple wire protocols within the unified model of RMI. The wire protocols are defined in terms of pluggable transport protocol service providers that may be added to the system at any time. A suite of protocols with varying properties can then be used seamlessly and collectively. This approach facilitates applications that communicate with different classes of peers using various protocols, applications that are protocol-independent and migratable between different protocols, or distributed systems with dynamic peerto-peer protocol negotiation. Additionally, enhancements to the RMI model towards multi-user environments are proposed. We describe the design and implementation of the framework, and present two transport service providers: the JRMPX provider using the standard RMI wire protocol (JRMP), and the XSOAP provider using SOAP. We include benchmark results demonstrating performance characteristics of these two providers in comparison to standard RMI.