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This article proposes a new analytical method of determining occupancy distribution and blocking probability in multiservice switching networks with admission control mechanisms and resource management mechanisms. The proposed method is a universal one, which allows for determining blocking probability using the same model, regardless of the type of admission control mechanisms and resource management mechanisms. The versatility of the method is demonstrated in the article for two selected mechanisms, i.e. a threshold mechanism and a resource reservation mechanisms. The switching networks under consideration are offered multiservice traffic streams, generated by the so-called multiservice sources, according to Erlang, Engset and Pascal distributions. The proposed method is based on a generalised way of determining traffic characteristics for inter-stage links of switching networks with resource and call management mechanisms. Particular attention is given to determining the influence of the introduced mechanisms in outgoing links of the switching network on the traffic properties of inter-stage links of the network. The results of analytical calculations are then compared with the results obtained in digital simulation for a number of selected switching networks.

DWDM networks make use of optical switching networks that allow light waves of multiple lengths to be serviced and provide the possibility of converting them appropriately. Research work on optical switching networks focuses on two main areas of interest: new non-blocking structures for optical switching networks and finding traffic characteristics of switching networks of the structures that are already well known. In practical design of switching nodes in optical networks, in many cases, the Clos switching networks are successfully used. Clos switching networks are also used in Elastic Optical Networks that can effectively manage allocation of resources to individual multi-service traffic streams. The research outcomes presented in this article deal with the problems of finding traffic characteristics in blocking optical switching networks with known structures. This article aims at presenting an analysis of the influence of traffic management threshold mechanisms on the traffic characteristics of multi-service blocking Clos switching networks that are used in the nodes of elastic optical networks as well as their influence on the traffic efficiency of network nodes. The analysis was carried out on the basis of research studies performed in a specially dedicated purpose-made simulation environment. The article presents a description of the simulation environment used in the experiments. The study was focused on the influence of the threshold mechanism, which is one of the most commonly used and elastic traffic management mechanisms, and on the traffic characteristics of switching networks that service different mixtures of multi-service Erlang, Engset and Pascal traffic streams. The conducted study validates the operational effectiveness and practicality of the application of the threshold mechanism to model traffic characteristics of nodes in an elastic optical network.

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With the ever-increasing demand for bandwidth, appropriate mechanisms that would provide reliable and optimum service level to designated or specified traffic classes during heavy traffic loads in networks are becoming particularly sought after. One of these mechanisms is the resource reservation mechanism, in which parts of the resources are available only to selected (pre-defined) services. While considering modern elastic optical networks (EONs) where advanced data transmission techniques are used, an attempt was made to develop a simulation program that would make it possible to determine the traffic characteristics of the nodes in EONs. This article discusses a simulation program that has the advantage of providing the possibility to determine the loss probability for individual service classes in the nodes of an EON where the resource reservation mechanism has been introduced. The initial assumption in the article is that a Clos optical switching network is used to construct the EON nodes. The results obtained with the simulator developed by the authors will allow the influence of the introduced reservation mechanism on the loss probability of calls of individual traffic classes that are offered to the system under consideration to be determined.

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This article discusses a discretized model of resources to which a mixture of multi-service traffic streams is offered and the connections of individual traffic classes that require a large number of allocation units are always executed using adjacent allocation units. The necessity of occupying the adjacent allocation units is typical, for example, for elastic optical networks, in which these units are termed frequency slots. The present article proposes a new occupancy distribution specially designed for these systems. The new occupancy distribution discussed in the article is based on the approximation of the service process by a reversible Markov process. A particular attention is given to the method for the calculations of the so-called conditional transition probability of the transitions between neighboring states in the Markov process. The analytical results of the modeling are compared with the results of simulations of corresponding network systems.