Using Differentiated Services Mechanisms to Improve Network Protocol and Application Performance

The differentiated services architecture (diffserv) includes lightweight mechanisms for service differentiation in the Internet. The primary motivation for diffserv has been enabling differentiation at a coarse granularity such as individual ISP customers. In this paper, we argue that the same or similar lightweight mechanisms could be employed fruitfully at a much finer granularity such as individual packets. The key benefit this would offer is that the sending host could exercise control on a much finer time-scale than traditional end-to-end mechanisms permit. We discuss several instances in the context of end-to-end protocols and applications where such enhanced control could help improve performance. We focus specifically on the TCP protocol and the Web browsing application, neither of which has received much attention in the traditional QoS research literature.