| This research attempts to determine the possibility of finding "simple" approximated rule(s) to control new incoming traffic flows (accept/reject) while satisfying the Quality-of-Service of all traffic by means of connection admission control (CAC) under differential service (DiffServ) Networks. The study is done in statistical simulations based on a queuing process simulator called CAC SIM. The current program is only able to simulate quality of service (QoS) of single link network with different traffic sources, capable of supporting DiffServ, and export data for admission region plots.;The resulting admission regions are often linear or trapezoidal, and the linear approximations would be conservative. When the higher priority QoS agreements are better than the lower priority QoS agreements, priority queuing (PQ) has larger admission region than round robin (RR). If both have similar QoS agreements and similar traffic characteristics, RR would have larger admission region than PQ. Weighted round robin (WRR) always lies in between PQ and WRR.;For the traffic characteristics, the admission region size is directly proportional to the packet size, the packet inter-arrival time, the server capacity, etc. For the QoS agreements, looser QoS agreements would often increase the admission region size (not directly proportional). However, the jitter behaves differently when there are fewer number of traffic sources in the network. An increase of the number of traffic flows may improve the jitter performance.;In general, for every possible number of one type of traffic source, we ask the question of what is the maximum number of a second type of traffic source that would still satisfy the QoS agreement (using CAC SIM). By connecting these points, we obtain the admission region curve, and the admission region is the area under the curve. |
