Optimizing a CORBA IIOP Protocol Engine for Minimal Footprint Multimedia Systems

Communication software for hand-held devices must be flexible and efficient to deliver the necessary Quality of Service (QoS) to multimedia applications such as real-time audio and video, video on-demand, electronic mail and fax, and Internet telephony. CORBA Object Request Brokers (ORBs) are an emerging middleware standard targeted for distributed applications. The stringent memory constraints imposed by handheld device hardware necessitates a minimal footprint for ORB-based applications. This paper provides three contributions to developing efficient ORB middleware for hand-held devices. First, we describe protocol implementation optimizations we employed to develop a timeand space-efficient interpretive IIOP protocol engine. Second, we describe IDL compiler optimizations for generating efficient stubs and skeletons that use our IIOP protocol engine. Finally, we empirically compare the performance and memory footprint of interpretive marshaling versus compiled marshaling for a wide range of IDL data types. Our optimizations to the interpretive IIOP protocol engine improve its performance substantially and it is now comparable the performance of compiled marshaling. Moreover, our IDL compiler optimizations yielded stubs and skeletons whose footprint is substantially smaller than those using compiled marshaling.