Analysis of feasible transport layer protocols for real-time data transmission in Diffserv networks

As real-time applications such as video and audio increase rapidly, it requires the Internet, to provide some quality of service (QoS) guarantees. DiffServ (Differentiated Service) is an emerging technology designed for supporting different levels of services including time-sensitive delivery over the Internet. In this paper, supposing that unidirectional streaming video data is transmitted over a DiffServ network, we have carried out a simulation experiment to evaluate the performance of existing transport layer protocols such as TCP and UDP, and tried to find out which shows better performance. From our experimental results, we know that when congestion happens and packets begin to be lost, TCP which has a reliable delivery mechanism behaves better than UDP. Furthermore, if deploying TCP with the SACK option, its rapid loss recovery function leads to even higher performance. So under our experimental environment, we conclude that TCP is an effective transport layer protocol for real-time data transmission in DiffServ networks.