Prioritized Congestion Control with Explicit Congestion Notification for TCP

摘要

In the TCP, the congestion detection by communication timeout is used for the end-to-end congestion control. However, it is not able to reflect the exact congestion status in the inside of the network, especially to wide area networks. To improve this problem, in addition to the existent methods, the explicit congestion notification is proposed to notify the congestion status through routers in the network. The one of its famous methods is the RED (Random Early Detection) gateway. By the way, in general, communicated data are classified into delay sensitive ones and others. If the congestion control reflects the priorities with respect to such communication qualities required by services, it can be expected to improve the utilization of the entire network. This paper expands the explicit congestion notification of the RED gateway for prioritized communications. The priorities are expressed by the one of the IPv6. The congestion control extension header is defined and the congestion control algorithm for the priorities is proposed. Finally, the network simulation under the nearer conditions to the real network concludes that the proposed method can provide the priority control on data traffic, while it keeps the average throughput similar to the one of the ordinary ones.