TCP flow performance guarantee in DiffServ networks

Recently, there has been increasing interest in providing differentiated services over the TCP/IP networks. One important network architecture is Differentiated Services (DiffServ). While the end-to-end feedback-based congestion control of TCP is very effective in achieving high throughput and avoiding congestion, many studies have shown that TCP flows suffer serious throughput and fairness problems in DiffServ networks. In this paper, we will study how to provide service guarantee for TCP flows in DiffServ networks. We will show that it is the lack of coordination between the flow control of TCP and traffic control of DiffServ that leads to the difficulty of performance guarantee. Based on the analytical study of flow throughput, we developed a new scheme(TCPTC) for better TCP flow conditioning. Simulations results have shown that this new algorithm outperforms the proposed schemes by a large margin. In the best of our knowledge, this is the first scheme that supports TCP flow performance guarantee in DiffServ networks and requires no modification of TCP congestion control protocol.