47 research outputs found
Quality of service technologies for multimedia applications in next generation networks
Next Generation Networks are constantly evolving towards solutions that allow the operator to provide advanced multimedia applications with QoS guarantees in heterogeneous, multi-domain and multi-services networks. Other than the unquestionable advantages inherent the ability to simultaneously handle traffic flows at different QoS levels, these architectures require management systems to efficiently perform quality guarantees and network resource utilization. These issues have been addressed in this thesis.
DiffServ-aware Traffic Engineering (DS-TE) has been considered as reference architecture for the deployment of the quality management systems. It represents the most advanced technology to accomplish either network scalability and service granularity goals. On the basis of DS-TE features, a methodology for traffic and network resource management has been defined. It provides some rules for QoS service characterization and allows to implement Traffic Engineering policies with a class-based approach. A set of basic parameters for quality evaluation has been defined, that are the Key Performance Indicators; some mathematical model to derive the statistical nature of traffic have been analyzed and an algorithm to improve the fulfillment of quality of service targets and to optimize network resource utilization. It is aimed at reducing the complexity inherent the setting of some of the key parameters in the NGN architectures. Multidomain scenarios with technologies different from DS-TE have been also evaluated, defining some methodologies for network interoperability. Simulations with Opnet Modeler confirmed the efficacy of the proposed system in computing network configurations with QoS targets.
With regard to QoS performance at the application level, video streaming applications in wireless domains have been particularly addressed. A rate control algorithm to adjust the rate on a per-window basis has been defined, making use of a short-term prediction of the network delay to keep the probability of playback buffer starvation lower than a desired threshold during each window.
Finally, a framework for mutual authentication in web applications has been proposed and evaluated. It integrates an IBA password technique with a challenge-response scheme based on a shared secret key for image scrambling. The wireless environment is mainly addressed by the proposed system, which tries to overcome the severe constraints on security, data transmission capability and user friendliness imposed by such environment
Supporting Service Differentiation in Multi-domain Multilayer Optical Networks
Providing differentiated quality of service became more and more important. This is not only because some service requests a high quality and real time transportation, but also because other services such as the capacity greedy applications request a higher bandwidth. In the meantime, has been the hybrid architecture consists of IP/MPLS domain and ASON/GMPLS optical domain projected as the infrastructure of the future internet. This architecture supports the transportation of the in near future expected data traffic on the ASON/GMPLS over DWDM optical domain, whereas it supports all the IP based service applications using the IP/MPLS domain. However, supporting service differentiation in multi-domain multilayer optical networks require the invention on routing scheme that supports both routing policies, the Physical Topology First (PTF) and Virtual Topology First (VTP), which are used to accommodate traffic in multilayer networks. In this work we use a hierarchical routing algorithm to evaluate the service differentiation schemes that are known in the literature in an IP/MPLS over ASON/GMPLS multi-domain network scenario, these service differentiation schemes are the Routing Policy Differentiation (RPD), Virtual Topology Differentiation (VTD) and Virtual Topology Sharing (VTS). 
Resource allocation in cellular CDMA systems with cross- layer Optimization
Ph.DDOCTOR OF PHILOSOPH
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.
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
Internet Protocol/MultiProtocol Label Switching (IP/MPLS) Networks
This paper discusses different aspects of Multi-Protocol Label Switching (MPLS) networks. In this paper, we first discussed MPLS in detail, the technology was developed to advance the IP network
Preemption control of multi-class loss networks
This thesis addresses the analysis and optimization of preemption in multi-class loss networks. Preemption, admission control and rate adaptation, are control mechanisms that enable loss network operators to provide quality of service (QoS) guarantees for admitted calls. This research includes two parts: i) performance characterization of a two parallel link loss network servicing multiple classes of calls under a speci c preemption and admission policy, and ii) preemption and admission control policy analysis for a single loss link servicing two classes of calls.In Part I, we consider a two parallel link multi-class loss network, where a call may preempt, if necessary, any calls with lower priorities and may in turn be preempted by any calls with higher priorities. The preemption policy permits both preemption from a preferred link to a backup link if possible, and eviction from either link if necessary. Our contributions in this part include: i) characterizing the rates of each class causing preemption of active lower priority calls, and therates of each class being preempted by an arriving higher priority call in Erlang-B functions when all classes share a common service rate; ii) simple expressions of these preemption rates through uniform asymptotic approximation; and iii) asymptotic approximation of these preemption rates using nearly completely decomposable (NCD) Markov chain techniques when classes have individual service rates.After analyzing the performance of a typical policy, we would also like to study various policies. In Part II, we analyze di erent preemption and admission control policies for a two-class loss link where per-class revenue is earned per unit time for each active call, and an instantaneous preemption cost is incurred whenever the preemption mechanism is employed. Our contributions in this part include: i) showing that under reasonable reward models, if we always preempt when the link is full, then it is better not to preempt at non-full states; ii) a su cient condition under which the average revenue of optimal preemption policy without admission control exceeds that of optimal admission control policy without preemption, which are established via policy improvement theorems fromstochastic dynamic programming.Ph.D., Computer Engineering -- Drexel University, 201
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A Connection Admission Control Framework for UMTS based Satellite Systems.An Adaptive Admission Control algorithm with pre-emption control mechanism for unicast and multicast communications in satellite UMTS.
In recent years, there has been an exponential growth in the use of
multimedia applications. A satellite system offers great potential for
multimedia applications with its ability to broadcast and multicast a large
amount of data over a very large area as compared to a terrestrial system.
However, the limited transmission capacity along with the dynamically
varying channel conditions impedes the delivery of good quality multimedia
service in a satellite system which has resulted in research efforts for deriving
efficient radio resource management techniques. This issue is addressed in
this thesis, where the main emphasis is to design a CAC framework which
maximizes the utilization of the scarce radio resources available in the
satellite and at the same time increases the performance of the system for a
UMTS based satellite system supporting unicast and multicast traffic.
The design of the system architecture for a UMTS based satellite system is
presented. Based on this architecture, a CAC framework is designed
consisting of three different functionalities: the admission control procedure,
the retune procedure and the pre-emption procedure. The joint use of these
functionalities is proposed to allow the performance of the system to be
maintained under congestion. Different algorithms are proposed for different
functionalities; an adaptive admission control algorithm, a greedy retune
algorithm and three pre-emption algorithms (Greedy, SubSetSum, and
Fuzzy).
A MATLAB simulation model is developed to study the performance of the
proposed CAC framework. A GUI is created to provide the user with the
flexibility to configure the system settings before starting a simulation. The
configuration settings allow the system to be analysed under different
conditions.
The performance of the system is measured under different simulation
settings such as enabling and disabling of the two functionalities of the CAC
framework; retune procedure and the pre-emption procedure. The simulation
results indicate the CAC framework as a whole with all the functionalities
performs better than the other simulation settings