End-to-End Latency Prediction for General-Topology Cut-Through Switching Networks

Low latency networking is gaining attention to support futuristic network applications like the Tactile Internet with stringent end-to-end latency requirements. In realizing the vision, cut-through (CT) switching is believed to be a promising solution to significantly reduce the latency of today's store-and-forward switching, by splitting a packet into smaller chunks called flits and forwarding them concurrently through input and output ports of a switch. Nevertheless, the end-to-end latency performance of CT switching has not been well studied in heterogeneous networks, which hinders its adoption to general-topology networks with heterogeneous links. To fill the gap, this paper proposes an end-to-end latency prediction model in a heterogeneous CT switching network, where the major challenge comes from the fact that a packet's end-to-end latency relies on how and when its flits are forwarded at each switch while each flit is forwarded individually. As a result, traditional packet-based queueing models are not instantly applicable, and thus we construct a method to estimate per-hop queueing delay via M/G/c queueing approximation, based on which we predict end-to-end latency of a packet. Our extensive simulation results show that the proposed model achieves 3.98-6.05% 90th-percentile error in end-to-end latency prediction

Quality of Service over Specific Link Layers: state of the art report

The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service

Klausurtagung des Instituts für Telematik. Schloss Dagstuhl, 29. März bis 1. April 2000

Der vorliegende Bericht gibt einen Überblick über aktuelle Forschungsarbeiten des Instituts für Telematik an der Universität Karlsruhe (TH). Das Institut für Telematik ist in einem Teilgebiet der Informatik tätig, welches durch das Zusammenwachsen von Informatik und Kommunikationstechnik zur Telematik geprägt ist. Es gliedert sich in die Forschungsbereiche Telematik, Telecooperation Office (TecO), Cooperation & Management, Hochleistungsnetze und Netzwerkmanagement sowie dezentrale Systeme und Netzdienste. Die Schwerpunkte des Forschungsbereichs "Telematik" (Prof. Dr. Dr. h.c. mult. G. Krüger) liegen in den Bereichen "Dienstgüte", "Mobilkommunikation" und "Verteilte Systeme". Gemeinsames Ziel ist die Integration heterogener Netze (Festnetze und Funknetze), Rechnersysteme (von Workstations bis zu PDAs) und Softwarekomponenten, um damit den Anwendern eine Vielzahl von integrierten Diensten effizient und mit größtmöglicher Qualität zu erbringen. Das "Telecooperation Office" (TecO, Prof. Dr. Dr. h.c. mult. G. Krüger) ist ein Institutsbereich, der in Zusammenarbeit mit der Industrie anwendungsnahe Forschungsthemen der Telematik aufgreift. Im Mittelpunkt steht die innovative Nutzung von Kommunikationsinfrastrukturen mit den Schwerpunkten Softwaretechnik für Web-Anwendungen, neue Formen der Telekooperation sowie tragbare und allgegenwärtige Technologien (Ubiquitous Computing). Die Kernkompetenz des Forschungsbereichs "Cooperation & Management" (Prof. Dr. S. Abeck) liegt im prozessorientierten Netz-, System- und Anwendungsmanagement. Es werden werkzeuggestützte Managementlösungen für Betriebsprozesse entwickelt und in realen Szenarien erprobt. Ein wichtiges Szenario stellt das multimediale Informationssystem "NEXUS" dar, das als Plattform eines europaweit verteilten Lehr- und Lernsystems genutzt wird. Der Forschungsbereich "Hochleistungsnetze & Netzwerkmanagement" (Prof. Dr. W. Juling) befasst sich mit Technologie und Konzepten moderner leistungsfähiger Netzwerke sowie darüber hinaus mit sämtlichen Aspekten des Managements dieser zumeist ausgedehnten Netze. Um eine enge Abstimmung zwischen Forschungsaktivitäten und betrieblicher Praxis zu erzielen, werden insbesondere auch Synergien zwischen Institut und Rechenzentrum angestrebt. Die Arbeiten des Forschungsbereichs "Dezentrale Systeme und Netzdienste" (Prof. Dr. L. Wolf) befassen sich mit der Unterstützung verteilter Multimedia-Systeme, auch unter Berücksichtigung von Komponenten mit drahtlosem Zugang und den dafür geeigneten Architekturen und Infrastrukturen. Dabei werden vor allem Aspekte der Kommunikationssysteme wie Protokollmechanismen, Ressourcenverwaltung und adaptive und heterogene Systeme untersucht

Voice packet delay evaluation in an IP network using voice stream multiplexing scheme

Orientador: Shusaburo MotoyamaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Neste estudo são avaliados o desempenho e o impacto do tráfego de voz em uma rede IP. Na rede IP o sinal de voz é transmitido através de pacotes que são identificados por um conjunto de cabeçalhos. Cada pacote de voz tem a carga útil, composta por um quadro (frame) de voz, muito menor que a carga útil de um pacote de dados. Desta forma, a rede IP pode tornar-se pouco eficiente para transportar sinal de voz. Além disso, o serviço de voz requer também interatividade o que implica em realocar, através de mecanismos apropriados, os recursos da rede IP. Uma das técnicas que pode ser usada é a aplicação de política de priorização do tráfego de voz que em contrapartida pode degradar o desempenho de tráfego com prioridade menor. A previsão de tráfego de voz crescente na rede IP pode torná-la bastante ineficiente, além de degradar o desempenho do tráfego de dados. Para minimizar este problema o esquema de multiplexagem dos quadros de voz pode ser usado. Um modelo matemático é proposto neste estudo para analisar o impacto do tráfego do pacote de voz em uma rede IP. O estudo é conduzido considerando-se sem e com a aplicação de multiplexagem de quadros de voz nos pacotes de voz e o parâmetro de desempenho é o atraso de cada pacote na rede IP. Em seguida, um outro modelo mais complexo, com fontes de voz ON-OFF e de dados do tipo HTTP, é simulado no ambiente do MatLab/SimEvent para o mesmo cenário estudado no modelo analítico. Os resultados obtidos mostraram que o comportamento da rede IP é similar tanto no modelo analítico como no modelo simulado e que a técnica de multiplexagem dos quadros de voz é um esquema eficiente para economizar a largura de banda de um enlace da rede IP.Abstract: In this study, the performance and impact of voice traffic in an IP network are evaluated. In the IP network, the voice signal is transmitted through packets that are identified by a set of headers. Each voice packet has payload composed of one voice frame, which is smaller than the payload of data packet. In this way, the IP network may become ineffective to carry the voice signal. Furthermore, the voice service also requires interactivity which means the need for reallocation, through appropriate mechanisms, the resources of the IP network. One of the techniques may be used is through the adoption of voice traffic priority policy which on other hand it may degrade the performance of data traffic with lower priority. The expected fast growing of voice traffic in IP network can make it inefficient as well as to degrade the data traffic performance. To minimize this problem the voice stream multiplexing scheme can be used. A mathematical model is proposed in this study to examine the impact of voice packet traffic in an IP network. The study is carried out considering with and without the application of voice frame multiplexing and the performance parameter is the delay of each packet in the IP network. Then, a more complex model, with ONOFF voice sources and data sources of HTTP type, is simulated in MatLab/SimEvent environment for the same scenario used in analytical model. The obtained results showed that the IP network behavior is similar in both analytical and simulated models and that voice frame multiplexing technique is an efficient scheme to save the bandwidth of a link.MestradoTelecomunicações e TelemáticaMestre em Engenharia Elétric

Traffic Engineering And Supporting QoS

ABSTRACT Traffic Engineering describes techniques for optimising network performance by measuring, modelling, characterizing and controlling Internet traffic for specific performance goals [11]. This is a comprehensive definition. Traffic engineering performance goals typically fall into one of two categories. The first one is traffic related performance objectives such as minimizing packet loss, lowering end-to-end delay, or supporting a contracted Service Level Agreement (SLA). The second category is efficiency related objectives, such as balancing the distribution of traffic across available bandwidth resources. Traffic related performance goals are set in order to meet contracted service levels and offer competitive services to customers. Efficiency related goals, are required by the service provider to minimize the cost of delivering services, especially the cost of utilizing expensive network resources. The objective of this thesis is to present a description of Multi Protocol Label Switching (MPLS) architecture and its functionality to achieve a tool for performing traffic engineering and QoS support. We simulate traffic engineering with MPLS on a simple network and measure its performance. We analyse measurements related to queuing delay, throughput and other traffic related issues. We then move on fine-tuning the MPLS-TE network to also take into consideration QoS support when aggregating flows through a single label- switching path. We combine differentiated services with MPLS architecture in order to support QoS requirements. The simulation tool used in this thesis is called OPNET Modeler version 8.11

Architecture and prototype of an optical UNI for the GIGA network

Orientador: Mauricio Ferreira MagalhãesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Os principais interesses do Projeto GIGA são o desenvolvimento de Tecnologias de Redes Ópticas, Serviços e Aplicações de Rede, Serviços Experimentais de Telecomunicações e Aplicações Científicas. No contexto deste Projeto, nosso grupo de pesquisa tem trabalhado no desenvolvimento de um Plano de Controle IP/WDM para integrar a Rede Cliente IP/MPLS com a Rede Óptica de Transporte WDM, de acordo com as especificações GMPLS e ASON. Especificamente neste trabalho é proposta uma Arquitetura para a UNI (User Network Interface) independente de protocolo de sinalização para prover a integralização entre as Redes Cliente e a Rede Óptica de Transporte. A Arquitetura da UNI proposta neste trabalho mantém inalterada a semântica de sinalização das redes cliente e de transporte da rede de testes do Projeto GIGA. Esta dissertação descreve como a Arquitetura desenvolvida suporta a independência quanto ao protocolo de sinalização e apresenta o protótipo implementado para validar a Arquitetura propostaAbstract: The main interests of the GIGA Project are the deployment of Optical Network Technology, Network Services and Applications, Experimental Telecommunication Services and Scientific Applications. In the context of this Project, our research group has been working on the design of an IP/WDMControl Plane to integrate the IP/MPLS Client Network with the Optical Transport Network (WDM), according to the GMPLS and ASON specifications. Specifically in this work is proposed a signaling protocol independent UNI (User Network Interface) architecture to integrate the Client and the Optical Transport Networks. The proposed UNI architecture maintains unchanged the client and transport networks signaling semantics for the GIGA testbed network. This dissertation describes how the designed architecture supports the independence of the signaling protocol and presents the prototype implemented to validate the architectureMestradoEngenharia de ComputaçãoMestre em Engenharia Elétric

Методи розрахунку пропускної здатності та продуктивності гілок мережі MPLS при обслуговуванні голосових повідомлень

Дисертація присвячена розробки методів оцінки якості обслуговування і пропускної спроможності мережі MPLS при обробці голосових повідомлень. Розроблено математичну модель функціонування мережі MPLS в режимі обслуговування голосових повідомлень, дана модель дозволяє провести декомпозицію мережі на окремі напрямки зв'язку, поставити у відповідність напрямку відповідний LSP мережі MPLS, привести модель до стандартної СМО. Удосконалено метод розрахунку пропускної здатності мережі MPLS відмінністю від існуючих є те, що введено етап прогнозування імовірності втрат на тунелях мережі до етапу розподілу навантаження. Удосконалено метод розрахунку необхідної продуктивності гілок мережі MPLS за показниками пропускної спроможності. Зменшена обчислювальна складність при однозначному визначенні порядку вибору для розрахунку напрямків зв'язку, а також підвищена точність отриманих результатів