An Experimental Evaluation of DCCP Transport Protocol: A Focus on the Fairness and Hand-Off over 802.11g Networks

This paper presents an experimental study of streaming multimedia packets using DCCP transport protocol over 802.11 g networks. Our main focus is to study the behavior of DCCP flows over real-time multimedia applications. The approach taken was to use DCCP flows in the presence of TCP and UDP flows, then analyze the behavior of each protocol, mainly in regards to the congestion control algorithms of both protocols. Furthermore, we also considered end-points mobility requirements, such as hand-off between multiples access points. Needless to say, the DCCP protocol was recently standardized by IETF as an alternative for streaming multimedia flows on computer networks. Before that, developers had to choose between either TCP or UDP as their transport protocol to stream multimedia packets. However, the lack of some features in both cases makes DCCP an interesting alternative for this kind of application. Therefore, the results presented in this paper show that TCP and DCCP protocols can share the network bandwidth without affecting each other. On the other hand, UDP flows can aggressively degrade TCP and DCCP flows due to the absence of any kind of flow control. Although UDP flows reach high bandwidth throughput, it loses a considerable amount of data taking into account limited bandwidth channels, such as 802.11 g networks. Finally, this work also shows that TCP and DCCP can think of loss of packets as network congestion while experimenting hand-offs, thus decreasing their throughput.