01072nas a2200133   4500000000100000008004100001260001200042100001600054700002400070700001600094245012100110490000700231520070000238       2021                            d  c07/20211 aTomasz Nycz1 aTadeusz Czachórski1 aMonika Nycz00aDiffusion Model of Preemptive-Resume Priority Systems and Its Application to Performance Evaluation of SDN Switches.0 v213 a<p>The increasing use of Software-Defined Networks brings the need for their performance analysis and detailed analytical and numerical models of them. The primary element of such research is a model of a SDN switch. This model should take into account non-Poisson traffic and general distributions of service times. Because of frequent changes in SDN flows, it should also analyze transient states of the queues. The method of diffusion approximation can meet these requirements. We present here a diffusion approximation of priority queues and apply it to build a more detailed model of SDN switch where packets returned by the central controller have higher priority than other packets.</p>