Output traffic analysis of a leaky bucket traffic shaper fed by a bursty source

Abstract

A leaky bucket traffic shaper, consisting of an infinite data buffer and a finite token pool, and fed by a bursty ON/OFF source, is considered. Tokens are generated periodically. Assuming geometrically distributed ON and OFF periods, the system is analyzed by means of a generating functions approach. A method for calculating the exact steady-state distributions of the data-buffer and the token-pool occupancies as well as the cell waiting times in the leaky bucket is presented. Also, a technique to derive the joint probability generating function of two consecutive interdeparture times at the output of the traffic shaper is described. From this pgf, closed-form expressions can be obtained for the variance of the interdeparture times and the correlation between two successive interdeparture times. The results are illustrated by means of some numerical examples and the influence of both the input-traffic characteristics and the leaky-bucket parameters on the output-traffic characteristics is investigated.<>