Experimental issues in design and implementation of the BODBA protocol

We report some experimental issues related to the implementation of the BODBA protocol. BODBA, which stands for the Best effort delivery of the on demand bandwidth allocation, is a layer two protocol for satellite communication. It uses statistical TDM in out-route and MF-TDMA, multifrequency time division multiple access, in the in-route. This requires scheduling some of the tasks periodically, and consequently, using an operating system with real-time capabilities. Even though the protocol has been designed for a relatively slow medium, below 10 Mbps, implementing it in a general propose operating system such as LINUX and meeting all requirements was challenging in practice. Our experience proved that not taking into account the overall performance in development cycle of the protocol could be a disaster. Techniques employed to optimize the code are explained. Some of the techniques arc the familiar classic techniques to optimize the code. However, the authors are not aware of any paper addressing all of them. In particular, the protocol has been implemented in multithread and scheduling them profoundly affects the system performance.