which was published in IEEE Journal on Selected Areas in Communications, vol.SAC-4, no.6, pp.802-812, September 1986.
We first consider the interdeparture process of a symmetric polling system with single buffer at each station, where distributions of transmission times and switchover times are assumed to be general. Under the assumption that consecutive interdeparture times are independent, the probability distribution is analyzed and the Laplace-Stieltjes transform is given. Numerical examples show that the coefficient of variation of interdeparture times is not monotomic with respect to the arrival rate. Based on the analysis, we can obtain the characteristics of outbound traffic if we are concerned with unidirectional traffic flow. In general, however, there is inbound traffic from external networks in the interconnected communication system and its effect on performance characteristics should be taken into account. We next propose the model of a polling system having traffic from outside the system. The model consisits of homogeneous stations with single buffers and a depot station with infinite buffer where inbound traffic is dealt with. We analyze the model and obtain the throughput and mean waiting time for the case of constant transmission times and constant switchover times. Numerical examples show that throughput of the system is not sensitive to inbound traffic if the total load of the system is moderate.
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