XTPX transport system for flexible QoS support of multimedia applications

This paper describes design, implementation aspects and usage of a transport system based on XTPX (eXpress Transfer Protocol eXtended) for flexible Quality of Service (QoS) support of multimedia applications in a heterogeneous network, operating system and workstation environment. We focus especially on protocol mechanisms providing specific multimedia requirements. Rate control techniques for synchronization and bundling of multimedia connections as well as for multimedia traffic “squeezing” to control the discrete time independent (asynchronous) media used simultaneously with continuous time dependent (isochronous) media. Throughput scalability support based on dynamic rate control and threshold QoS monitoring using the XTPX Management Information Base. Adaptive acknowledgment and retransmission techniques considering QoS requirements (throughput, delay, delay jitter) of specific media data and different network conditions (ATM, LAN, satellite). The usage of these mechanisms is demonstrated with scenarios and performance measurements in PC environment on top of Ethernet network