154 research outputs found
E3MS: A traffic engineering prototype for autoprovisioning services in IP/DiffServ/MPLS networks
This paper presents the testbed definition, implementation and trials of a new strategy for traffic autoprovisioning for MPLS and IP/DiffServ. This is the proof of concept of a new scenario for traffic engineering, for selfconfiguring control and end-to-end quality of service management by means of a tool based on Web Services. The system is structured in 3 layers: A Graphical User Interface, a Network Elements layer (an interface to physical devices) and, in the middle, a Network Management System layer, where decisions about admission, load balancing, path selection, rerouting and bandwidth allocation per class are taken. The system includes Dynamic Resource Allocation (DRA) and Background Monitoring System (BMS) modules to globally manage network resources. The so-called Squatter and Legalization mechanisms are introduced as novelties added to traffic engineering. Those strategies permit the use of part of the available resources from other classes only while unused by the class owning them. The trials hav validated the management system, using Cisco routers.Postprint (published version
Theories and Models for Internet Quality of Service
We survey recent advances in theories and models for Internet Quality of Service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also briefly discussed. We then turn our attention to statistical performance guarantees, and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review recent proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support
A QoS-enabled resource management scheme for F-HMIPv6 micro mobility approach
In the near future, wireless networks will certainly run real-time applications with special Quality of Service (QoS) requirements. In this context micro mobility management schemes such as Fast Handovers over Hierarchical Mobile IPv6 (F-HMIPv6) will be a useful tool in reducing Mobile IPv6 (MIPv6) handover disruption and thereby to improve delay and losses. However, F-HMIPv6 alone does not support QoS requirements for real-time applications. Therefore, in order to accomplish this goal, a novel resource management scheme for the Differentiated Services (DiffServ) QoS model is proposed to be used as an add-on to F-HMIPv6. The new resource management scheme combines the F-HMIPv6 functionalities with the DiffServ QoS model and with network congestion control and dynamic reallocation mechanisms in order to accommodate different QoS traffic requirements. This new scheme based on a Measurement-Based Admission Control (MBAC) algorithm is effective, simple, scalable and avoids the well known traditional resource reservation issues such as state maintenance, signaling overhead and processing load. By means of the admission evaluation of new flows and handover flows, it is able to provide the desired QoS requirements for new flows while preserving the QoS of existing ones. The evaluated results show that all QoS metrics analyzed were significantly improved with the new architecture indicating that it is able to provide a highly predictive QoS support to F-HMIPv6
Advances in Internet Quality of Service
We describe recent advances in theories and architecture that support performance guarantees needed for quality of service networks. We start with deterministic computations and give applications to integrated services, differentiated services, and playback delays. We review the methods used for obtaining a scalable integrated services support, based on the concept of a stateless core. New probabilistic results that can be used for a statistical dimensioning of differentiated services are explained; some are based on classical queuing theory, while others capitalize on the deterministic results. Then we discuss performance guarantees in a best effort context; we review: methods to provide some quality of service in a pure best effort environment; methods to provide some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support
Scalable Bandwidth Management in Software-Defined Networks
There has been a growing demand to manage bandwidth as the network traffic increases. Network applications such as real time video streaming, voice over IP and video conferencing in IP networks has risen rapidly over the recently and is projected to continue in the future. These applications consume a lot of bandwidth resulting in increasing pressure on the networks. In dealing with such challenges, modern networks must be designed to be application sensitive and be able to offer Quality of Service (QoS) based on application requirements. Network paradigms such as Software Defined Networking (SDN) allows for direct network programmability to change the network behavior to suit the application needs in order to provide solutions to the challenge. In this dissertation, the objective is to research if SDN can provide scalable QoS requirements to a set of dynamic traffic flows. Methods are implemented to attain scalable bandwidth management to provide high QoS with SDN. Differentiated Services Code Point (DSCP) values and DSCP remarking with Meters are used to implement high QoS requirements such that bandwidth guarantee is provided to a selected set of traffic flows. The theoretical methodology is implemented for achieving QoS, experiments are conducted to validate and illustrate that QoS can be implemented in SDN, but it is unable to implement High QoS due to the lack of implementation for Meters with DSCP remarking. The research work presented in this dissertation aims at the identification and addressing the critical aspects related to the SDN based QoS provisioning using flow aggregation techniques. Several tests and demonstrations will be conducted by utilizing virtualization methods. The tests are aimed at supporting the proposed ideas and aims at creating an improved understanding of the practical SDN use cases and the challenges that emerge in virtualized environments. DiffServ Assured Forwarding is chosen as a QoS architecture for implementation. The bandwidth management scalability in SDN is proved based on throughput analysis by considering two conditions i.e 1) Per-flow QoS operation and 2) QoS by using DiffServ operation in the SDN environment with Ryu controller. The result shows that better performance QoS and bandwidth management is achieved using the QoS by DiffServ operation in SDN rather than the per-flow QoS operation
Implementation and Performance Evaluation of an NGN prototype using WiMax as an Access Technology
Telecommunications networks have evolved to IP-based networks, commonly known as Next Generation Networks (NGN). The biggest challenge in providing high quality realtime multimedia applications is achieving a Quality of Service (QoS) consistent with user expectations. One of the key additional factors affecting QoS is the existence of different QoS mechanisms on the heterogeneous technologies used on NGN platforms. This research investigates the techniques used to achieve consistent QoS on network technologies that use different QoS techniques. Numerous proposals for solving the end-to-end QoS problem in IP networks have adopted policy-based management, use of signalling protocols for communicating applications QoS requirements across different Network Elements and QoS provisioning in Network Elements. Such solutions are dependent on the use of traffic classification and knowledge of the QoS requirements of applications and services on the networks. This research identifies the practical difficulties involved in meeting the QoS requirements of network traffic between WiMax and an IP core network. In the work, a solution based on the concept of class-of-service mapping is proposed. In the proposed solution, QoS is implemented on the two networks and the concept of class-of-service mapping is used to integrate the two QoS systems. This essentially provides consistent QoS to applications as they traverse the two network domains and hence meet end-user QoS expectations. The work is evaluated through a NGN prototype to determine the capabilities of the networks to deliver real-time media that meets user expectations
A QoS-aware architecture for mobile internet
Tese de doutoramento InformáticaHoje em dia, as pessoas pretendem ter simultaneamente mobilidade, qualidade de serviço e
estar sempre connectados à Internet. No intuito, de satisfazer estes clientes muito exigentes,
os mercados das telecomunicações estão a impor novos e dificeis desafios às redes móveis,
através da demanda, de heterogeneidade em termos de tecnologias de acesso rádio, novos
serviços, niveis de qualidade de serviço adequados aos requisitos das aplicações de tempo
real, elevada taxa de utilização do recursos disponiveis e melhor capacidade de desempenho.
A Internet foi concebida para fornecer serviços sem qualquer tipo de garantias de qualidade
à s aplicações, apenas se comprometendo em oferecer o melhor serviço possÃvel. No
entanto, nos útlimos anos diversos esforços foram levados a cabo no sentido de dotar a
Internet com o suporte à qualidade de serviço. Dos esforços desenvolvidos resultaram
dois paradigmas para o suporte da qualidade de serviço: o modelo de Serviços Integrados
(Integrated Services - IntServ) e o modelo de Serviços Diferenciados (Differentiated Services
- DiffServ). Todavia, estes modelos de qualidade de serviço (QoS) foram concebido antes
da existência da Internet móvel, portanto o desenvolvimento destes modelos não teve em
consideração a questão da mobilidade.
Por outro lado, o protocolo padrão actual para a Internet móvel, o MIPv6, revela algumas
limitações nos cenários onde os utilizadores estão constantemente a moverem-se para
outros pontos de acesso. Neste tipo de cenários, o MIPv6 introduz tempos de latência que
não são sustentáveis para aplicações com requisitos de QoS mais restritos. Os factos revelados,
demonstram que existe uma emergente necessidade de adaptar o actual protocolo de
mobilidade, e também de adaptar os modelos de QoS, ou então criar modelos alternativos
de QoS, para satisfazer às exigências do utilizador de hoje de redes móveis.
Para alcançar este objectivo o presente trabalho propõe melhorias no sistema de gestão
da mobilidade do protocolo MIPv6 e na gestão de recursos do modelo DiffServ. O MIPv6 foi
melhorado para os cenários de micro-mobilidade com a abordagem para micro-mobilidade do F-HMIPv6. Enquanto que, o modelo DiffServ foi melhorado para os ambientes móveis
com funcionalidades dinâmicas e adaptativas através da utilização de sinalização de QoS e
da gestão distribuida dos recursos.
A gestão da mobilidade e dos recursos foi também acoplada na solução proposta com o
propósito de optimizar a utilização dos recursos num meio onde os recursos são tipicamente
escassos.
O modelo proposto é simples, é de fácil implementação, tem em consideração os requisitos
da Internet móvel, e provou ser eficiente e capaz de fornecer serviços com QoS de
elevada fiabilidade às aplicações.Over the last few years, several network communication challenges have arisen as a
result of the growing number of users demanding Quality of Service (QoS) and mobility
simultaneously.
In order to satisfy these very demanding customers, the markets are imposing new
challenges to wireless networks by demanding heterogeneity in terms of wireless access
technologies, new services, suited QoS levels to real-time applications, high usability and
improved performance.
However, the Internet has been designed for providing application services without quality
guarantees. That explains why, in the last years several efforts have been made to
endow Internet with QoS support. From the developed efforts have resulted two QoS
paradigms: Integrated Services (IntServ) which offers the guaranteed service model and
the Differentiated Services (DiffServ) which offers the predictive service model.
Although these QoS models have been designed before the existence of mobile Internet,
so they do not consider the mobility issue. For instance, the guaranteed service model
requires that whenever a Mobile Node (MN) wants to move to a new location, the allocated
resources in the old path must be released and a new resource reservation in a new path must
be made, resulting in extra signaling overhead, heavy processing and state load. Therefore,
if handovers are frequent, large mobility and QoS signaling messages will be created in
the access networks. Consequently, significant scalability problems may arise with this type of
service model.
The predicted service model, on the other hand, requires an additional features such
as dynamic and adaptive resource management in order to be efficient in a very dynamic
network such as a mobile network.
A QoS solution for mobile environments must provide the capacity to adapt its resource
utilization to a changeable nature of wireless networks because they have a more dynamic behavior due to incoming or outgoing handovers. For this reason, a QoS signalization for
dynamic resource provisioning is necessary in order to supply adequate QoS levels to mobile
users.
On the other hand, the current standard protocol for mobile Internet, Mobile IPv6
(MIPv6), reveals limitations in scenarios where users are constantly moving to another
point of attachment. In these situations, MIPv6 introduces latency times that are not
sustainable for applications with strict QoS requirements.
All things considered, reveal the emerging need to adapt the current standard mobility
protocol and QoS models to satisfy today’s mobile user’s requirements.
To accomplish this goal, the present work proposes enhancements in terms of the MIPv6
protocol mobility management scheme as well as in DiffServ QoS model resource management.
The former was enhanced for micro-mobility scenarios with a specific combination of
FMIPv6 (Fast Mobile IPv6) and HMIPv6 (Hierarchical Mobile IPv6) protocols. Whereas,
the latter was enhanced for mobile environments with dynamic and adaptive features by
using QoS signalization as well as distributed resource management.
The mobility and resource management has also been coupled in the proposed solution
with the objective of optimizing the resource utilization in a environment where resources
are typically scarce.
In order to assess model performance as well as its parametrization, a simulation model
has been designed and implemented in the Network Simulator version two (NS-2).
The model´s performance evaluation has been conducted based on the respective data
acquired from statistical analysis in order to validate and consolidate the conclusions. Simulation
results indicate that the solution avoids network congestion and starvation of less
priority DiffServ classes.
Moreover, the results also indicate that bandwidth utilization for priority classes increases
and the QoS offered to MN’s applications, in each DiffServ class, remains unchangeable
with MN mobility.
The proposed model is simple and easy to implement. It considers mobile Internet
requirements and has proven to be effective and capable of providing services with highly
reliable QoS to mobile applications.Fundação para a Ciência e a Tecnologia (FCT) - Bolsa SFRH/BD/35245/200
Admission control in multiservice IP networks : architectural issues and trends
The trend toward the integration of current and emerging applications and services in the Internet has launched new challenges regarding service deployment and management. Within service management, admission control (AC) has been recognized as a convenient mechanism to keep services under controlled load and assure the required QoS levels, bringing consistency to the services offered. In this context, this article discusses the role of AC in multiservice IP networks and surveys current and representative AC approaches. We address and compare the architectural principles of these AC approaches and their main features, virtues and limitations that impact on the quality control of network services. We identify important design aspects that contribute to the successful deployment of flexible and scalable AC solutions in multiservice networks
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