Onsatsim: a simulation tool for for on-board satellite switching systems

In this paper we will present the model for on-board satellite switching networks that was used as the underlying model for ONSATSIM, a simulation package for the study of satellite networks with on-board switching that was developed by the authors, at Queen's University. We will also present the software implementation and validation procedure for ONSATSIM, and an example of its application by using it to obtain preliminary performance results for a proposed 2-bit/4-level reactive flow control discipline. In the past, communications satellites have essentially performed as amplifier/repeaters, with all switching, routing, network control, and signal processing functions performed by the earth stations. Recently, however, there has been a move towards multi-spot beam switching satellites, which will allow the satellite links to be integrated into the network at a much lower hierarchal level 14],[2). This is required in order for the satellites to be able to cope with the traflic resulting from the new trend towards VSAT (Very Small Aperture Terminal) packet switched networks. This trend is due to both the rapid drop in the prices of Earth station equipment, and the growing demand for ISDN services [3].