The EuQoS system: A solution for QoS routing in heterogeneous networks

EuQoS is the acronym for “end-to-end quality of service support over heterogeneous networks,”which is a European research project aimed at building an entire QoS framework,addressing all the relevant network layers, protocols, and technologies. This framework, which includes the most common access networks (xDSL, UMTS, WiFi, and LAN) is being prototyped and tested in a multidomain scenario throughout Europe, composing what we call the EuQoS system. In this article we present the novel QoS routing mechanisms that are being developed and evaluated in the framework of this project. The preliminary performance results validate the design choices of the EuQoS system, and confirm the potential impact this project is likely to have in the near future.Postprint (published version

Implementation and performance analysis of a QoS-aware TFRC mechanism

This paper deals with the improvement of transport protocol behaviour over the DiffServ Assured Forwarding (AF)class. The Assured Service (AS) provides a minimum throughput guarantee that classical congestion control mechanisms, like window-based in TCP or equation-based in TCP-Friendly Rate Control (TFRC), are not able to use efficiently. In response, this paper proposes a performance analysis of a QoS aware congestion control mechanism, named gTFRC, which improves the delivery of continuous streams. The gTFRC (guaranteed TFRC) mechanism has been integrated into an Enhanced Transport Protocol (ETP) that allows protocol mechanisms to be dynamically managed and controlled. After comparing a ns-2 simulation and our implementation of the basic TFRC mechanism, we show that ETP/gTFRC extension is able to reach a minimum throughput guarantee whatever the flow’s RTT and target rate (TR) and the network provisioning conditions

gTFRC: a QoS-aware congestion control algorithm

This study addresses the end-to-end congestion control support over the DiffServ Assured Forwarding (AF) class. The resulting Assured Service (AS) provides a minimum level of throughput guarantee. In this context, this paper describes a new end-to-end mechanism for continuous transfer based on TCP-Friendly Rate Control (TFRC) originally proposed in [11]. The proposed approach modifies TFRC to take into account the QoS negotiated. This mechanism, named gTFRC, is able to reach the minimum throughput guarantee whatever the flow's RTT and target rate. Simulation measurements show the efficiency of this mechanism either in over-provisioned or exactly-provisioned network. In addition, we show that the gTFRC mechanism can be used in the same DiffServ/AF class with TCP or TFRC flows

Network emulation focusing on QoS-Oriented satellite communication

This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication

GTFRC, a TCP friendly QoS-aware rate control for diffserv assured service

This study addresses the end-to-end congestion control support over the DiffServ Assured Forwarding (AF) class. The resulting Assured Service (AS) provides a minimum level of throughput guarantee. In this context, this article describes a new end-to-end mechanism for continuous transfer based on TCP-Friendly Rate Control (TFRC). The proposed approach modifies TFRC to take into account the QoS negotiated. This mechanism, named gTFRC, is able to reach the minimum throughput guarantee whatever the flow’s RTT and target rate. Simulation measurements and implementation over a real QoS testbed demonstrate the efficiency of this mechanism either in over-provisioned or exactly-provisioned network. In addition, we show that the gTFRC mechanism can be used in the same DiffServ/AF class with TCP or TFRC flows

A study of packet losses in the EuQoS network

As Internet usage grows, more efforts are put into analyzing its internal performance, usually such analysis comes through simulation using different models. While simulation can provide a good approximation of network behavior, modeling such a complex network as the Internet is very difficult if not impossible. This paper studies the network’s performance from an experimental point of view using the EuQoS project’s overlay network as a testbed. In the framework of the EuQoS project, many performance tests have been done for proving the reliability of the data transmission. The tests show some rough edges which need further analysis, the most important being random packet losses in UDP flows, and a great amount of out of order packets. This paper focuses on the study of such packet losses, searching for their causes, and more importantly, to show their effects on real-time traffic such as VoIP. As a basis for comparison, the paper also uses TCP traffic to relate the performance of bulk data transfer versus the sustained rate of UDP/RTP flows used for real-time applications. To achieve this goal, several applications are used to generate and capture such traffic and measure its behavior at network level.Peer ReviewedPostprint (author’s final draft

Selected Issues of QoS Provision in Heterogenous Military Networks

Tactical ad-hoc networks are evolving today towards complex heterogeneous networks in terms of architecture, protocols and security. Due to the difference in network resources and reliability, end-to-end quality of service provisioning becomes very challenging. If we also take into account communication issues such as unpredictable connectivity, preferential forwarding for special traffic classes, intermittency due to node or communication link failure, the problem is further aggravated.In this article, we examine the major challenges that must be solved in order to provide efficient QoS provisioning in the heterogeneous network. Finally we describe QoS-aware mechanisms for inter-domain and intra-domain heterogeneous networks, also including real-time services provision in highly mobile environments.

Distributed Sampling for On-line SLA Assessment

New business infrastructures over the Internet pose a new set of traffic constraints. In particular, multimedia and interactive contents require guarantees of bandwidth and delivery time. The broad deployment and real-time nature of this class of applications require the provisioning of specific resources in the network to guarantee a certain level of Quality of Service (QoS). QoS techniques need ways of obtaining feedback about the status of the QoS enabled paths, for example, for checking the fulfilment of Service Level Agreements (SLA). A possible technique for obtaining such feedback is by passively monitoring the network traffic. The issue with traffic monitoring is the additional bandwidth needed by the control traffic generated by the different collection points in order to synchronise its acquired QoS metrics. Moreover, passive monitoring at line speed is an expensive process both in terms of resource consumption and price. However, some of these requirements can be significantly reduced by using traffic sampling. This paper presents a novel methodology for intra-domain on-line distributed QoS monitoring, which makes an efficient use of the network resources by employing distributed sampling mechanisms. The proposal is validated by performing real tests on an European-wide testbed. Our results show that the sampling technique can significantly reduce the traffic overhead, while obtaining very accurate estimations of the One Way Delay performance metricPostprint (published version

Autorização de serviços com garantias de QoS baseada em perfis de usuário

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.Vários trabalhos recentes propõem soluções de QoS permitindo que os usuários especifiquem explicitamente a qualidade de serviço requisitada durante a chamada invocação explícita de serviço com QoS. Esta flexibilidade requer uma negociação dinâmica de QoS, incluindo novos mecanismos para autenticação, autorização e contabilidade (AAA). Em especial, uma organização deveria ser capaz de controlar o uso dos serviços de rede, de modo a atender aos seus objetivos de negócios, autorizando somente serviços de rede com QoS baseados em regras de destino de serviços, de aplicações e de usuários. Esta dissertação trata do modelo do conjunto de dados e conhecimentos para suportar o processo de concessão de autorização para requisições de acesso a serviços com requisitos de QoS, e propõe um modelo de perfil de usuário para autorização de serviços com QoS, baseado em uma descrição semântica do SLA contratado com a operadora, utilizando uma ontologia para a definição de conceitos empregados. Nesta proposta, os usuários podem ser classificados de acordo com as necessidades das funções que exercem em perfis específicos. Cada perfil de usuário indica os serviços que onusuário está autorizado a requisitar, seus limites de consumo e escopo. Políticas de autorização baseadas em perfil de usuário podem ser definidas e executadas durante a invocação de serviços com QoS explícita. Recent works propose QoS solutions allowing the users to explicitly specify the quality level they are requesting, during a so-called explicit QoS service invocation. This flexibility requires dynamic QoS service negociation including new mechanisms for authentication, authorization and accounting (AAA). In particular, an organization should be able to control their network services usage so as to support their main business objectives, by bauthorizing only network QoS services based on service destinations, applications and users to support the authoriza ion concession of explicit QoS services requests and proposes a user profile model for QoS service authorization, based on a semantic description of the SLA signed with the NSP, using an ontology for the definition of applied concepts. In this proposal, the users may be classified according to their job activities into specific profiles. Each user profile indicates the services that the user is authorized to request, their consumption limits and scope. User profile-based authorization polices may be defined and executed during explicit QoS service invocations

Progettazione e Realizzazione del Modulo di "Traffic Engineering" nell'Ambito della Piattaforma e-learning del progetto EuQoS (EU)

The aim of this thesis work is to develop the Traffic Engineering e-learning course among the EuQoS project. This e-learning system provides theory section concerning know-how about the dealt technology, interactive animations and a remotely accessible laboratory to run network simulation