System dynamics simulation of computer networks: Price-controlled QoS framework

The dynamics of computer networks was until recently modelled mostly with discrete-event simulations and queuing systems. Modern computer networks are becoming large and complex, and discrete-event simulation schemes are too slow to successfully model their behavior. Researchers and engineers are switching to more novel approaches, like fluid simulation schemes, where network elements are described as fluid servers which process workload continuously, yet the traffic source can be of arbitrary type, including discrete-event source and fluid source. We are developing this idea further and propose even simpler schema, using the systems dynamics simulation approach in our schema, the network topology and routing information is represented by relatively simple matrix algebra. The schema can be used to model computer systems for various purposes, from the topology and capacity design and optimization in every day practice, to more theoretical work like testing new technology and policy approaches. Besides the formal description of the proposed schema, the paper also gives an example of its adaptation to model the behavior of a price-controlled end-to-end QoS provision in computer networks.