Overload control using rate control throttle: selecting token bank capacity for robustness to arrival rates

The design of rate-control throttles, which are used for overload control of computer and communication networks is discussed. An analysis of the rate-control throttle is presented. It is found that if the token bank capacity is 10 or more and if jobs arrive as a Poisson process, then for many practical applications in digital switching systems and telecommunication networks the control settings can be set independently of the arrival rate and need only be adjusted for changes in the desired departure rate. If the arrival of jobs is bursty (coefficient of variation of interarrival times is greater than 1), then the robustness declines but may remain quite good, depending on parameter values. The rate-control throttle with any token bank capacity is significantly more robust to arrival rates than either a percent-blocking throttle or a call-gapping throttle