QUEUING ANALYSIS OF A JOCKEYING MODEL

In this paper, we solve a type of shortest queue problem, which is rel ated to multibeam satellite systems. We assume that the packet interar rival times are independently distributed according to an arbitrary di stribution function, that the service times are Markovian with possibl y different service rates, that each server has its own buffer for pac ket waiting, and that jockeying among buffers is permitted. Packets al ways join the shortest buffer(s). Jockeying takes place as soon as the difference between the longest and shortest buffers exceeds a preset number (not necessarily 1). In this case, the last packet in a longest buffer jockeys instantaneously to the shortest buffer(s). We prove th at the equilibrium distribution of packets in the system is modified v ector geometric. Expressions of main performance measures, including t he average number of packets in the system, the average packet waiting time in the system, and the average number of jockeying, are given. B ased on these solutions, numerical results are computed. By comparing the results for jockeying and nonjockeying models, we show that a sign ificant improvement of the system performance is achieved for the jock eying model.