CAM04-2: A Congestion Control Method Jointly Utilizing Delay and Marking/Loss Feedback

Depending upon the type of feedback that is utilized, network congestion control schemes can be classified into two categories: marking/loss based (e.g., TCP Reno) or delay based (e.g., TCP Vegas). Delay-based schemes have garnered much attention due to their higher network throughput than loss-based methods. Delay provides a much finer-grained measure of congestion than packet loss or packet marking feedback. However, when there are multiple bottleneck links or inadequate buffer sizes in the path between a source and destination, delay information alone is insufficient for revealing the incipient network congestion. In this paper, we consider the design of a congestion control scheme that transcends the two normal categories and instead jointly exploits both delay and marking/loss feedback. In particular, we introduce the concept of normalized queuing delay, and demonstrate how a controller based on joint feedback provides high throughput even under highly dynamic network conditions as evidenced by ns2 simulations.