Quality-of-service management in IP networks

Quality of Service (QoS) in Internet Protocol (IF) Networks has been the subject of active research over the past two decades. Integrated Services (IntServ) and Differentiated Services (DiffServ) QoS architectures have emerged as proposed standards for resource allocation in IF Networks. These two QoS architectures support the need for multiple traffic queuing systems to allow for resource partitioning for heterogeneous applications making use of the networks. There have been a number of specifications or proposals for the number of traffic queuing classes (Class of Service (CoS)) that will support integrated services in IF Networks, but none has provided verification in the form of analytical or empirical investigation to prove that its specification or proposal will be optimum. Despite the existence of the two standard QoS architectures and the large volume of research work that has been carried out on IF QoS, its deployment still remains elusive in the Internet. This is not unconnected with the complexities associated with some aspects of the standard QoS architectures. [Continues.

Delay analysis for wireless applications using a multiservice multiqueue processor sharing model

The ongoing development of wireless networks supporting multimedia applications requires service providers to efficiently deliver complex Quality of Service (QoS) requirements. The wide range of new applications in these networks significantly increases the difficulty of network design and dimensioning to meet QoS requirements. Medium Access Control (MAC) protocols affect QoS achieved by wireless networks. Research on analysis and performance evaluation is important for the efficient protocol design. As wireless networks feature scarce resources that are simultaneously shared by all users, processor sharing (PS) models were proposed for modelling resource sharing mechanisms in such systems. In this thesis, multi-priority MAC protocols are proposed for handling the various service traffic types. Then, an investigation of multiservice multiqueue PS models is undertaken to analyse the delay for some recently proposed wireless applications. We start with an introduction to MAC protocols for wireless networks which are specified in IEEE standards and then review scheduling algorithms which were proposed to work with the underlying MAC protocols to cooperatively achieve QoS goals. An overview of the relevant literature is given on PS models for performance analysis and evaluation of scheduling algorithms. We propose a multiservice multiqueue PS model using a scheduling scheme in multimedia wireless networks with a comprehensive description of the analytical solution. Firstly, we describe the existing multiqueue processor sharing (MPS) model, which uses a fixed service quantum at each queue, and correct a subtle incongruity in previous solutions presented in the literature. Secondly, a new scheduling framework is proposed to extend the previous MPS model to a general case. This newly proposed analytical approach is based on the idea that the service quantum arranged by a MAC scheduling controller to service data units can be priority-based. We obtain a closed-form expression for the mean delay of each service class in this model. In summary, our new approach simplifies MAC protocols for multimedia applications into an analytical model that includes more complex and realistic traffic models without compromising details of the protocol and significantly reduces the number of MAC headers, thus the overall average delay will be decreased. In response to using the studied multiservice multiqueue PS models, we apply the MPS model to two wireless applications: Push to Talk (PTT) service over GPRS/GSM networks and the Worldwide Interoperability for Microwave Access (WiMAX) networks. We investigate the uplink delay of PTT over traditional GPRS/GSM networks and the uplink delay for WiMAX Subscriber Station scheduler under a priority-based fair scheduling. MAC structures capable of supporting dynamically varying traffic are studied for the networks, especially, with the consideration of implementation issues. The model provides useful insights into the dynamic performance behaviours of GPRS/GSM and WiMAX networks with respect to various system parameters and comprehensive traffic conditions. We then evaluate the model under some different practical traffic scenarios. Through modelling of the operation of wireless access systems, under a variety of multimedia traffic, our analytical approaches provide practical analysis guidelines for wireless network dimensioning

ADAPTIVE CAPACITY ALLOCATION IN MPLS NETWORKS

Traffic Congestion is one of the salient issues that affect overall network performance. Network traffic has become very dynamic due to a variety of factors, such as, the number of users varies with time of the day, multimedia applications, bursts in traffic due to a failure and so on. Recently, Multi-Protocol Label Switching (MPLS) networks have emerged as a technology with many promising features such as traffic engineering, QoS provisioning, and speeding up the traffic transmission. However, MPLS still suffers from the nonstationary/transient conditions that sometimes cause congestion. Actually, congestion does not always occur when the network is short capacity, but rather, when the network resources are not efficiently utilized. Thus, it is very important to develop an algorithm that efficiently and dynamically adjusts the available capacity. In this thesis, we propose an adaptive capacity allocation scheme. We have started our consideration with a single traffic class system that has dynamic traffic where traffic arrival is considered at the level of connection/call arrival. We assume that the virtual network for this traffic class operates as a loss system; i.e. if a connection does not find bandwidth, the connection is blocked and cleared from the system. Then, we extended our work to include the multiple traffic classes. Two cases have been studied and analyzed; when classes have no coupling and when they are coupled. The capacity allocation scheme is derived from a first-order, differential equation-based, fluid-flow model that captures the traffic dynamics. The scheme aims to maintain the connection blocking probability within a specified range by dynamically adjusting the allocated capacity. A fluid flow differential equation model is developed to model the changing traffic environment. Using the fluid flow model, Lyapunov Stability theory is used to derive a novel adaptive capacity adjustment scheme which guarantees overall system stability while maintaining the target QoS parameters. Numerical results are given which show that the Lyapunov control based scheme successfully provides the desired QoS requirements and performs better than existing schemes in the literature

JTIT

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Modelling, Dimensioning and Optimization of 5G Communication Networks, Resources and Services

This reprint aims to collect state-of-the-art research contributions that address challenges in the emerging 5G networks design, dimensioning and optimization. Designing, dimensioning and optimization of communication networks resources and services have been an inseparable part of telecom network development. The latter must convey a large volume of traffic, providing service to traffic streams with highly differentiated requirements in terms of bit-rate and service time, required quality of service and quality of experience parameters. Such a communication infrastructure presents many important challenges, such as the study of necessary multi-layer cooperation, new protocols, performance evaluation of different network parts, low layer network design, network management and security issues, and new technologies in general, which will be discussed in this book

Dynamic bandwidth allocation in ATM networks

Includes bibliographical references.This thesis investigates bandwidth allocation methodologies to transport new emerging bursty traffic types in ATM networks. However, existing ATM traffic management solutions are not readily able to handle the inevitable problem of congestion as result of the bursty traffic from the new emerging services. This research basically addresses bandwidth allocation issues for bursty traffic by proposing and exploring the concept of dynamic bandwidth allocation and comparing it to the traditional static bandwidth allocation schemes

Telecommunications Networks

This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing

On greening optical access networks

With the remarkable growth of fiber-based services, the number of FTTx subscribers has been dramatically increasing in recent years. Owing to the environmental concern, reducing energy consumption of optical access networks has become an important issue for network designers. In Ethernet passive optical network (EPON), the optical line terminal (OLT) located at the central office broadcasts the downstream traffic to all optical network units (ONUs), each of which checks all arrival downstream packets to obtain those destined to itself. Since traffic of ONUs changes dynamically, properly defining the sleep mode for idle ONUs can potentially save a significant amount of energy. However, it is challenging to shut down an ONU receiver as the ONU needs to receive some downstream control packets to perform upstream transmission. In this framework, a novel sleep control scheme is proposed to address the downstream issue which can efficiently put ONU receivers to sleep. This dissertation further defines multiple levels of power saving in which the ONU disables certain functions based on the upstream and downstream traffic load. The proposed schemes are completely compatible with the multi-point control protocol (MPCP) and EPON standards. Elimination of the handshake process makes the sleep control schemes more efficient. Currently, OLTs also consume a significant amount of energy in EPON. Therefore, reducing energy consumption of OLT is as important as reducing energy consumption of ONUs; such requirement becomes even more urgent as OLT keeps increasing its provisioning data rate, and higher data rate provisioning usually implies higher energy consumption. Thus, a novel energy-efficient OLT structure, which guarantees services of end users with a smallest number of power-on OLT line cards, is proposed. More specifically, the number of power-on OLT line cards is adapted to the real-time incoming traffic. Also, to avoid service disruption resulted by powering off OLT line cards, a proper optical switch is equipped in OLT to dynamically configure the communications between OLT line cards and ONUs. By deploying a semi-Markov based technique, the performance characteristics of the sleep control scheme such as delay and energy-saving are theoretically analyzed. It is shown that, with proper settings of sleep control parameters, the proposed scheme can save a significant amount of energy in EPON

Journal of Telecommunications and Information Technology, 2009, nr 3

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