Modelling Pascal traffic in overflow systems

In this paper, impact of changes in parameters of offeredtraffic on the accuracy of determining the parameters of overflowtraffic in hierarchy systemswithmulti-service traffic was presented. Pascal typetrafficstreamswereoffered to the consideredsystems. The study investigated the impact of changes in the number of sources, intensity of trafficoffered by individualclasses, as well as changes in the trafficoffered by single free source. The presentedresultsarebased on determined relative errors of the values of overflowtrafficobtained in simulations and on the basis of calculations

Properties of Recurrent Equations for the Full-Availability Group with BPP Traffic

The paper proposes a formal derivation of recurrent equations describing the occupancy distribution in the full-availability group with multirate Binomial-Poisson-Pascal (BPP) traffic. The paper presents an effective algorithm for determining the occupancy distribution on the basis of derived recurrent equations and for the determination of the blocking probability as well as the loss probability of calls of particular classes of traffic offered to the system. A proof of the convergence of the iterative process of estimating the average number of busy traffic sources of particular classes is also given in the paper

On IPv6 Experimentation in Wireless Mobile Ad Hoc Networks, Journal of Telecommunications and Information Technology, 2014, nr 3

With the growing interest towards the Internet of Things IPv6-based mobile ad hoc networks (MANETs) become a key enabling technology offering the possibility of automated, unsupervised network configuration and operation. Such a functionality calls for an accurate and reliable testing of the newly proposed solutions, which is challenging due to the dynamic, decentralized and ad hoc nature of MANETs. In this work selected topics are presented on performing IPv6 protocols experimentation in wireless, IPv6-only mobile ad hoc networks – including both simulation – and testbed-based evaluation. Based on the authors experience with the evaluation of the extended IPv6 Neighbor Discovery protocol (ND++) proposed during the course of research, the selection of an opensource simulation environment is presented and a comparison between simulation and emulation experimentation methods is provided. Benefits and drawbacks of both these methodologies for testing IPv6 solutions are depicted. Moreover, the important aspects of topology and mobility considerations are considered. Finally the authors propose a testing approach that would allow for a detailed and accurate evaluation by means of open-source, easily accessible and low-cost methodologies

Recurrent Method for Blocking Probability Calculation in Switching Networks with Overflow Links, Journal of Telecommunications and Information Technology, 2013, nr 1

This article presents a new recurrent method for modelling multi-service switching networks with overflow links. In the proposed method, the blocking probability for a given stage of the switching network is determined on the basis of the characteristics of the preceding stage. A particular attention is given to a possibility of a considerable reduction of the internal blocking probability of the switching network that would result from an application of additional overflow links between neighbouring switches of the first stage of the network. The results of the analytical modelling of selected multi-service switching networks with overflow links in the first stage are compared with the results of the simulation experiments. The study confirms the accuracy of all the adopted theoretical assumptions in the proposed analytical model of the multi-service switching network

Traffic Modeling in Industrial Ethernet Networks

This article discusses the traffic types typically used in industrial networks. The authors propose a number of methods of generating traffic that can be used in modeling traffic sources in the networks under consideration. The proposed traffic models have been developed on the basis of the ON/OFF model. The proposed solutions can be applied to model typical traffic types that are used in industrial systems, such as Time-Triggered (TT) traffic, Audio-Video Bridging (AVB) traffic or Best Effort traffic. The article discusses four traffic models with modifications and shows how the proposed models can be used in modeling different traffic types used in industrial networks

Packet switch architecture with multiple output queueing, Journal of Telecommunications and Information Technology, 2004, nr 4

In this paper the new packet switch architecture with multiple output queuing (MOQ) is proposed. In this architecture the nonblocking switch fabric, which has the capacity of NxN2, and output buffers arranged into N separate queues for each output, are applied. Each of N queues in one output port stores packets directed to this output only from one input. Both switch fabric and buffers can operate at the same speed as input and output ports. This solution does not need any speedup in the switch fabric as well as arbitration logic for taking decisions which packets from inputs will be transferred to outputs. Two possible switch fabric structures are considered: the centralized structure with the switch fabric located on one or several separate boards, and distributed structure with the switch fabric distributed over line cards. Buffer arrangements as separate queues with independent write pointers or as a memory bank with one pointer are also discussed. The mean cell delay and cell loss probability as performance measures for the proposed switch architecture are evaluated and compared with performance of OQ architecture and VOQ architecture. The hardware complexity of OQ, VOQ and presented MOQ are also compared. We conclude that hardware complexity of proposed switch is very similar to VOQ switch but its performance is comparable to OQ switch

Modelling Pascal traffic in overflow systems

In this paper, impact of changes in parameters of offered traffic on the accuracy of determining the parameters of overflow traffic in hierarchical systems with multi-service traffic was presented. Pascal type traffic streams were offered to the considered systems. The study investigated the impact of changes in the number of sources, intensity of traffic offered by individual classes, as well as changes in the traffic offered by a single free source. The presented results are based on determined relative errors of the values of overflow traffic obtained in simulations and on the basis of calculations

On Increasing the Accuracy of Modeling Multi-Service Overflow Systems with Erlang-Engset-Pascal Streams

In this article, we present an analysis of the accuracy level of methods for modeling the multi-service overflow systems that service Erlang, Engset, and Pascal traffic. In systems with traffic overflow, new calls that cannot be serviced by the primary resources are overflown (directed) to other available resources that can service a given call, that is, to the secondary resources (alternative resources). In the article, we focus on studying the influence of methods for determining the parameters of traffic that overflows to the secondary resources on the accuracy of determining the traffic characteristics of overflow systems. Our analysis revealed that the main source of the inaccuracy of the existing methods is their approach to determining both the average value and the variance of multi-service Pascal traffic streams offered to the secondary resources. Therefore, we proposed a new method for determining the parameters of Pascal overflow traffic. The method is based on the decomposition of multi-service primary resources into single-service resources and the subsequent conversion of Engset and Pascal streams into equivalents of Erlang traffic. The results of the analytical calculations obtained on the basis of the new method are then compared with the results of simulation experiments for a number of selected structures of overflow systems that service Erlang, Engset, and Pascal traffic. The results of the study indicate that the proposed theoretical model has a significantly higher accuracy than the models proposed in the literature. The method can be used in the analysis, dimensioning, and optimization of multi-service telecommunication systems composed of separated resources, for example, mobile cellular systems