Vladanka S. Acimovic-Raspopovic

End-to-end quality of service specification and mapping: The third party approach

This article addresses an open issue of end-to-end service specification and mapping in next generation networks. A centralized approach has been considered, via the third party agent that manages negotiation process in a group of domains. We suggest a general structure of the service specification form, which contains technical parameters related with a particular service request. Relying on such general form, we further propose and evaluate an efficient algorithm for service class selection. The algorithm selects the most appropriate class for each domain by determining the closest conformance between the required and offered service level. We also present a numerical example that demonstrates operating of the algorithm. Performance evaluation has been performed on the prototype implementation. Results of the analysis have pointed out the following important advantages of our approach: fairness in resource consumption, flexibility in class selection according to specific management policy and adaptability to different quality of service models.

Responsive pricing modeled with Stackelberg game for next-generation networks

In this paper, we study the problem of resource allocation between users in next-generation networks. The starting assumption is that the service provider tries to come up with convincing offers of service level to subscribers, based on demand responsive pricing scheme, while trying to maximize its profit. We developed two algorithms with different usage-based pricing strategies. Both algorithms solve pricing optimization problem using Stackelberg game with service provider acting as a leader and users behaving as followers. We developed the bandwidth management server to perform automatic optimal bandwidth allocation to each users session and maximize its expected utility while maximizing the overall service providers revenue. For both algorithms, we also performed the procedure for optimization of the capacity offered to users.

A heuristic algorithm for lightpath scheduling in next-generation WDM optical networks

We study the routing and wavelength assignment (RWA) problem of scheduled lightpath demands (SLDs) in all-optical wavelength division multiplexing networks with no wavelength conversion capability. We consider the deterministic lightpath scheduling problem in which the whole set of lightpath demands is completely known in advance. The objective is to maximize the number of established lightpaths for a given number of wavelengths. Since this problem has been shown to be NP complete, various heuristic algorithms have been developed to solve it suboptimally. In this paper, we propose a novel heuristic RWA algorithm for SLDs based on the bee colony optimization (BCO) metaheuristic. BCO is a newborn swarm intelligence metaheuristic approach recently proposed to solve complex combinatorial optimization problems. We compare the efficiency of the proposed algorithm with three simple greedy algorithms for the same problem. Numerical results obtained by numerous simulations performed on the widely used realistic European Optical Network topology indicate that the proposed algorithm produces better-quality solutions compared to those obtained by greedy algorithms. In addition, we compare the results of the BCO–RWA–SLD algorithm with four other heuristic/metaheuristic algorithms proposed in literature to solve the RWA problem in the case of permanent (static) traffic demands.

Dynamic routing design under forecast uncertainty

Forecast errors are always present in network design since they arise either from overestimation or underestimation of future network load. Routing design procedure can correct the forecast errors. In this paper the capacity management model based on load forecast and using the dynamic routing for correction of forecast errors is presented. The results of using preplanned and fixed routing procedures are analyzed and compared.

Quality of Service Negotiation in Next Generation Networks

This paper addresses different aspects of quality of service (QoS) negotiation in next generation networks. The differentiated services (DiffServ) framework is assumed in a multi-domain network core, while access networks may implement other QoS models. QoS negotiation results in service level agreement (SLA), i.e., a contract between the provider and the user, which defines technical, financial and legal aspects related with particular service. Solutions for SLA structure and format are discussed, with respect to mapping algorithms on the network-to-network interface. Considering conditions of contract violation, different traffic conditioning policies have been compared by computer simulation. We further provide a brief overview of the recently proposed next steps in signaling (NSIS) framework. The paper also addresses possibilities to achieve efficient usage based pricing in accordance with negotiated technical parameters from the SLA. Finally, we briefly present the object-oriented design and implementation of the application SLA Manager (SLAM), which is intended for QoS negotiation in DiffServ IP network.

The analysis of telecom operator's revenue dependence on different routing and interconnection charging methods

Abstract Telecommunication operators endeavour to offer their users numerous services and, at the same time, to be competitive with other operators at the market while accomplishing high revenue. The only way to achieve all those goals is to make better usage of their network resources and realise high network efficiency. In this paper, we tested the assumption that a proper combination of the different dynamic telecommunication traffic routing methods and interconnection charging methods can provide higher operators revenue. In order to analyze the effects of combinations of four different routing and two interconnection charging methods on operators revenue, we developed new software for simulation of network operations. This software is used for simulation of the three interconnected networks operators. Results considering the dependence of operators revenue on routing and interconnection charging methods combination are analyzed and discussed.

Load balance routing for interconnected next generation networks performances improvement

In this paper, results of extensive research concerning synergy of dynamic routing and interconnection charging methods are presented. The impact of various dynamic traffic routing methods on different performances of interconnected telecommunications network with the application of bill-and-keep interconnection charging is analysed. For the purpose of our research, we developed the software for Routing and Interconnection Simulation — RIS. Analysing obtained results we noticed that with application of some routing methods, there are several links completely unused. We introduce the new load balance routing method in order to improve some performances of interconnected next generation networks — NGN.

Competitive pricing using Cournot game in Next Generation Networks

This paper covers some important requirements for game theory based pricing of services in Next Generation Networks. We propose the Cournot game for modelling the competition between two service providers offering the same service. In this paper we analyze simulation results and found equilibrium price for one special case of the proposed model.

An Application of Game Theory for the Selection of Traffic Routing Method in Interconnected NGN

In this paper, the impact of various dynamic traffic routing methods on different performances of interconnected telecommunications network with the application of bill-and-keep interconnection charging is presented. For the purpose of our research, we developed the software for Routing and Interconnection Simulation (RIS). We conducted two-stage analysis. First stage is concerning the shortest path routing, the three-hop routing, the random path routing and the last successful path routing, and their influence on certain network performance parameters. In second stage the coordination game theory model is proposed in order to determine the one routing method that provides the best results for all operators in terms of costs per link.

Web based e-learning software for optical link design

In distance learning, web-based software may provide an alternative to installation of expensive software on the student computer, or an alternative to expensive laboratory equipment. This paper describes the original web-based e-learning software, which enables teaching and learning of the optical link design. Optical link design is an iterative process involving trade-offs to achieve the desired performance: bit error rate, transmission distance, etc., at minimal cost. Fundamental elements of an optical fiber transmission link are the optical transmitter, the optical fiber with associated splices and connectors, and the optical receiver. The student must select appropriate devices from a set of available optical components to meet a given set of system requirements. Data concerning optical equipment that can be used for specific optical link design are stored in a database, that was created for the purpose of this software.