OBEX is a session protocol designed to transmit data objects between resource-limited devices. It has been adopted as the framework for object exchange for wireless transports including IrDA and Bluetooth. A mathematical analysis for OBEX throughput-over the IrDA protocol stacks is carried out in this paper. OBEX maximum packet size and turnaround time are optimized for the system throughput. Numerical results show that OBEX throughput improves significantly by the optimization. We also offer suitable OBEX parameters selection guidelines for different data rates by considering the trade off between system performance and hardware requirements.