Enhancing accuracy of probe packet-based congestion detection in high speed networks

A general technique to detect and control congestion status for high speed packet networks is formulated and analyzed. The technique is based on the notion of detection interval, which represents the time to complete a basic congestion detecting interaction between a packet source and destination. The congestion detection consists of having the source send special probe packets during a specified period of time and then await the return of a feedback packet from the destination, which conveys the result of analysis performed by the destination upon receiving the probe packets. The source would adjust its behavior to accommodate the network status reported by the feedback packet. We measure the performance of our congestion detecting scheme in terms of the detecting accuracy. Our analysis is based on a two-state model of network operation wherein a hypoexponential distribution is used for congestion durations. Analyses of our model have resulted in strategies to enhance the detecting accuracy for network congestion. An easily calculated approximation to determine the probe packet delay for optimal performance is provided, which can be employed by the destination to set probe waiting time in the detection interval to enhance the detecting accuracy.