Joanna Weissenberg

Modeling Erlang's Ideal Grading with Multirate BPP Traffic

This paper presents a complete methodology for modeling gradings (also called non-full-availability groups) servicing single-service and multi-service traffic streams. The methodology worked out by the authors makes it possible to determine traffic characteristics of various types of gradings with state-dependent call arrival processes, including a new proposed structure of the Erlang’s Ideal Grading with the multirate links. The elaborated models of the gradings can be used for modeling different systems of modern networks, for example, the radio interfaces of the UMTS system, switching networks carrying a mixture of different multirate traffic streams, and video-on-demand systems. The results of the analytical calculations are compared with the results of the simulation data for selected gradings, which confirm high accuracy of the proposed methodology.

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.

The Queueing Model of a Multiservice System with Dynamic Resource Sharing for Each Class of Calls

The paper presents a new model of a multiservice queueing system with limited queue and state-dependent dynamic resource sharing of the server between individual classes of calls. The advantage of the proposed model is the possibility to evaluate the average parameters of queues for individual classes of calls. The proposed model can be taken as a basis for further research on multiservice queueing systems.

Lagrangian relaxation in the multicriterial routing

Communications networks routing is not a new subject. However, with a growth of packet networks and the increase of their range and importance, the task of conveying information over the web has grown beyond its original shape and has become far more sophisticated. It is no longer computer scientists and the military that make use of the global network exclusively; it can be stated that almost every possible group from the global population has numerous representatives among Internet users. This fact is coupled with a decrease in the popularity of the original communication media such as the telephone and the e-mail. This is mainly due to them being assimilated into packet networks along with the process of network convergence. A number of different types of information streams in packet networks has been observed and classified. It turns out that careful resources management itself may lead to an increase in the information transporting efficiency. In this paper, an approach is explored - the Lagrangian relaxation - that enables incorporating multiple criteria into the routing problem solution. At the same time, the low computation complexity is maintained that enables further consideration of the technique also in practical scenarios.

Queuing Model of the Access System in the Packet Network

This article proposes a new multi-dimensional Erlang’s Ideal Grading (EIG) model with queues that can service a number of call classes with differentiated access to resources. The model was used to determine delays and packet loss probabilities in the access system composed of a node in the operator’s network and a number of users. The analytical results obtained in the study were then compared with the results of a simulation, which confirmed the essential and required accuracy of the proposed model. The model developed in the study can be used to analyse, design and optimize present-day operator’s networks.

The Model of the DWDM Access Node

The following work presents an analytical model of a queuing system with a non-full-availability server and multi-service traffic. This model is then used for an analysis of a DWDM (Dense Wavelength Division Multiplexing) networks access node. Such an approach to DWDM node modeling enables the basic characteristics of the system to be determined and, in particular, allows the average waiting time for service to be estimated. This is of particular importance to operators that take advantage of DWDM networks to offer real-time services.

Queueing model of a multi-service system with elastic and adaptive traffic

Abstract This paper presents and discusses a multi-service model of a queueing system with elastic and adaptive traffic. The presented model permits to determine the characteristics of a multi-service queueing system, such as blocking probability or the average queueing length. The model can be used for analysis of modern network systems based on TCP/IP protocols, particularly the Internet.

The new approximative model of multiservice Erlang's ideal grading with queues

The paper presents a new approximate model for multi-service, non-full-availability queueing system. This model can be used to model the access nodes of the network. Due to the fact that this model is a approximate model, the results obtained were compared with the results of simulation experiments. The comparison has allowed us to confirm the correctness of the models assumptions.

A Model of Erlang's Ideal Grading with Multi-service Traffic Sources

The paper, Maciej presents a new model of Erlang’s Ideal Grading with multi-service traffic sources. Traffic sources of this kind correspond better with actual devices utilized by network users. As the proposed model is an approximate one, the results obtained with its help have been compared to the results of a computer simulation. The comparison has confirmed the correctness of the model’s theoretical assumptions. The new model may successfully be used for modeling modern communication systems.

Queuing models for wireless mesh networks

Abstract In this paper we discuss a proposition of various applications of new queueing models that have been developed within the CARMNET project in nodes of the mesh network. These models allow characteristics of systems that service multi-rate traffic to be determined, e.g., the average queue length or the average waiting time for calls of a given class. The proposed models can be used to design, analyse and optimize multiservice networks