Abstract: At Old Dominion University, we have designed and implemented a Java-based distance education system, which we term IRI-h (for Interactive Remote Instruction-heterogeneous). IRI-h is designed to function on a number of heterogeneous platforms, and within heterogeneous network environments. IRI-h builds on the success of its predecessor system IRI, but attempts to avoid a number of identified pitfalls and deficiencies such as platform dependence, poor scalability, and the need for a homogeneous controlled network environment. In this paper, we present the design and software architecture of IRI-h which continues to offer audio, video, and tool sharing services within a synchronous virtual classroom environment, albeit in a platform independent manner. Furthermore, the proposed architecture accommodates class participants with no multicast capabilities, or limited connectivity bandwidth by offering tunneling, and rate adaptation services.