A new packet marking strategy for explicit congestion notification in the internet

Abstract

A window-based flow control is a sort of feedback-based congestion control mechanisms, and has been widely used in current TCP/IP networks. In the feedback-based congestion control, feedback delay of the congestion information from the bottleneck node is one of the important elements that affect the performance. Recently, the use of an explicit congestion notification (ECN) mechanism as congestion indication from the network to source hosts has been actively discussed in the IETF. In this paper, we propose an enhanced marking strategy for ECN that can reduce the transfer delay of congestion information of a router in multiple-hop network environments. At a transit router, the proposed method relays the congestion experienced (CE)-bit contained in an incoming IP packet to the head-of-line packet with a corresponding flow which is waiting for transmission in the output buffer. Simulation results showed that ECN with the proposed mark-relay strategy produced a superior performance in terms of throughput and fairness between TCP flows.