| This thesis is concerned with the study of Collision-Avoidance Star Local Area Networks (CASLANs). CASLANs are a class of random access star local area networks in which packet collisions are avoided by using a number of hardware switches. The study is divided into three parts. The first is an indepth analysis of the behavior and performance of CASLANs. The second part involves analysis of CASLANs in a time-constrained environment. In the third part, prioritized CASLANs for data, and integrated voice/data applications are studied.; During the course of this study several contributions to the understanding of the behavior and performance of CASLANs are made: (1) It is shown that decreasing the propagation delay between the nodes and the central node does not always mean better performance. Indeed, it is shown that increasing the propagation delay may result in a much improved performance. Also, it is proven that by choosing the right network parameters, packets could be guaranteed transmission rights. (2) It is shown that CASLANs, under very heavy load, operate in a round robin fashion, and that the delay is bounded. (3) A study of CASLANs for real-time applications is conducted, in which it is shown that CASLANs perform very well in a time-constrained environment. As well, the performance of CASLANs in a prioritized environment is explored. It is shown that CASLANs are very good candidates for voice and data integration.; Also, several other contributions to modeling the performance of CASLANs are made: (1) An exact, heavy load, performance model of a class of CASLANs is introduced. This model is used to show that the delay of CASLANs, under heavy load conditions, is bounded. (2) A new performance model for CASLANs is introduced. The model follows a tagged user in an exact analysis, while the rest of the users' behavior is approximated by mimicking that of the tagged user at steady state. This model is more accurate than all earlier CASLANs performance models. (3) A hard real-time performance model of CASLANs is presented. In this model, packet laxities are assumed to be exponentially distributed and packets that exceed their laxities are removed from the system. (4) A prioritized CASLANs model for moderately loaded systems is introduced. |
