Abstrzict ' Elenientary congestion models sornetimes require analysis of G/Gfl systems with hyperexponentially distributed interarrival time and service time distributions. It is shown that for such systems, the ergodic waiting time distribution is itself hyperexponentially distributed, A siinple computational procedure is provided to find the parameters needed, Green's function methods are employed to motivate the factorization required, The releyance of these results to the delay in the overflow process of MIM!S is dis¢ ussed.

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