Measuring the Utilization of a Synchronous Data Link: An Application of Busy-Period Analysis

01 May 1980

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Measuring the Utilization of a Synchronous Data Link: An Application of Busy-Period Analysis By T. Y U M (Manuscript received August 29, 1979) The utilization of links in a communication network is an important and easily measurable quantity; it is the fraction of time that a link is busy. We focus on the estimation of link utilization through measurements and consider, in particular, the duration of measurement required for a prescribed accuracy of the estimate. Two conflicting factors involved in the choice of measurement time are the desirability of a measurement of short, and thus recent, duration and the desirability of an interval of sufficient duration to assure statistical accuracy. We assume that the composite input of messages to an outgoing buffer of a synchronous data link constitutes a Poisson process. The message length is arbitrarily distributed and is in units of "packets." This allows us to model the transmission facilities as a continuous-time-input, discrete-time-output MG 1 queue. We analyze the output process of such a system and determine the time needed to measure link utilization with a prescribed accuracy. We also present an application to the Common Channel Interoffice Signaling network as an illustration of the analysis.