A heterogeneous SCAN service polling model with single-message buffer

Abstract A performance analysis is given for a polling system in which the server polls N stations, back and forth, according to the so-called SCAN system. The arrangement of the stations along the line is symmetric, but in other respects the stations are not homogeneous. Messages arrive at station i in Poisson fashion at an average rate λ i . The number of characters in the messages received at station i has a geometric distribution with mean 1/ σ i . The service time per character at station i is a constant b i . The switchover time between adjacent stations is a constant r. An exact analysis is given, although because of associated computational problems this has limited application. Performance measures such as average polling cycle time, mean response time (at individual stations or overall) are easily calculated.