Overlay Multicast Networks: Elements, Architectures and Performance

To my beloved family. Today, the telecommunication industry is undergoing two important developments with implications on future architectural solutions. These are the irreversible move towards Internet Protocol (IP)-based networking and the deployment of broadband access. Taken together, these developments offer the opportunity for more advanced and more bandwidth-demanding multimedia applications and services, e. g., IP television (IPTV), Voice over IP (VoIP) and online gaming. A plethora of Quality of Service (QoS) requirements and facilities are associated with these applications, e. g., multicast facilities, high bandwidth and low delay/jitter. Moreover, the architectural solution must be a unified one, and be independent of the access network and content management. An interesting solution to these challenges is given by overlay multicast networks. The goal of these networks is to create and to maintain efficient multicast topologies among the multicast participants as well as to minimize th

Mätningar av en-vägskorsningstid i IP routrar

The main goals of this thesis are towards an understanding of the delay process in best-effort Internet for both non-congested and congested networks. A novel measurement system is reported for delay measurements in IP routers, which follows specifications of the IETF RFC 2679. The system employs both passive measurements and active probing and offers the possibility to measure and analyze different delay components of a router, e.g., packet processing delay, packet transmission time and queueing delay at the output link. Dedicated application-layer software is used to generate UDP traffic with TCP-like characteristics. Pareto traffic models are used to generate self-similar traffic in the link. The reported results are in form of several important statistics regarding processing and queueing delays of a router, router delay for a single data flow, router delay for multiple data flows as well as end-to-end delay for a chain of routers. They confirm results reported earlier about the fact that the delay in IP routers is generally influenced by traffic characteristics, link conditions and, to some extent, details in hardware implementation and different IOS releases. The delay in IP routers may also occasionally show extreme values, which are due to improper functioning of the routers. Furthermore, new results have been obtained that indicate that the delay in IP routers shows heavy-tailed characteristics, which can be well modeled with the help of several distributions, either in the form of a single distribution or as a mixture of distributions. There are several components contributing to the OWTT in routers, i.e., processing delay, queueing delay and service time. The obtained results have shown that, e.g., the processing delay in a router can be well modeled with the Normal distribution, and the queueing delay is well modeled with a mixture of Normal distribution for the body probability mass and Weibull distribution for the tail probability mass. Furthermore, OWTT has several component delays and it has been observed that the component delay distribution that is most dominant and heavy-tailed has a decisive influence on OWTT.Mätningar och modeller för en-vägskorsningstid presenteras

Overlay Multicast Networks : Elements, Architectures and Performance

Today, the telecommunication industry is undergoing two important developments with implications on future architectural solutions. These are the irreversible move towards Internet Protocol (IP)-based networking and the deployment of broadband access. Taken together, these developments offer the opportunity for more advanced and more bandwidth-demanding multimedia applications and services, e. g., IP television (IPTV), Voice over IP (VoIP) and online gaming. A plethora of Quality of Service (QoS) requirements and facilities are associated with these applications, e. g., multicast facilities, high bandwidth and low delay/jitter. Moreover, the architectural solution must be a unified one, and be independent of the access network and content management. An interesting solution to these challenges is given by overlay multicast networks. The goal of these networks is to create and to maintain efficient multicast topologies among the multicast participants as well as to minimize the performance penalty involved with application layer multicasting. Since they operate at the application layer, they suffer from two main drawbacks: higher delay and less efficient bandwidth utilization. It is therefore important to assess the performance of overlay multicast networks in “real- world”-like conditions. For this purpose, we first performed an in-depth measurement and modeling study of the packet delay at the network layer. The reported results are in the form of several important statistics regarding processing and queueing delays of a router. New results have been obtained that indicate that the delay in IP routers shows heavy-tailed characteristics, which can be well modeled with the help of several distributions, in the form of a single distribution or as a mixture of distributions. There are several components contributing to the delay in routers, i. e., processing delay, queueing delay and service time. It was observed that the component delay distribution that is most heavy-tailed has a decisive influence on delay. Furthermore, we selected three representative categories of overlay multicast networks for study, namely Application Level Multicast Infrastructure (ALMI), Narada and NICE is the Internet Cooperative Environment (NICE). The performance of these overlay multicast protocols was evaluated through a comprehensive simulation study with reference to a detailed set of performance metrics that captured application and network level performance. A particular interest was given to the issues of scalability, protocol dynamics and delay optimization as part of a larger problem of performance-aware optimization of the overlay networks. The simulations were configured to emulate “real-world”-like characteristics by implementing a heavy-tailed delay at the network level and churn behavior of the overlay nodes. A detailed analysis of every protocol is provided with regard to their performance. Based on our study, significant conclusions can be drawn regarding the scalability of the protocols with reference to overlay multicast group management, resource usage and robustness to churn. These results contribute to a deeper understanding of the requirements for such protocols targeted at, e. g., media streaming

Measurements and Models of One-Way Transit Time in IP Routers

The main goals of this thesis are towards an understanding of the delay process in best-effort Internet for both non-congested and congested networks. A novel measurement system is reported for delay measurements in IP routers, which follows specifications of the IETF RFC 2679. The system employs both passive measurements and active probing and offers the possibility to measure and analyze different delay components of a router, e.g., packet processing delay, packet transmission time and queueing delay at the output link. Dedicated application-layer software is used to generate UDP traffic with TCP-like characteristics. Pareto traffic models are used to generate self-similar traffic in the link. The reported results are in form of several important statistics regarding processing and queueing delays of a router, router delay for a single data flow, router delay for multiple data flows as well as end-to-end delay for a chain of routers. They confirm results reported earlier about the fact that the delay in IP routers is generally influenced by traffic characteristics, link conditions and, to some extent, details in hardware implementation and different IOS releases. The delay in IP routers may also occasionally show extreme values, which are due to improper functioning of the routers. Furthermore, new results have been obtained that indicate that the delay in IP routers shows heavy-tailed characteristics, which can be well modeled with the help of several distributions, either in the form of a single distribution or as a mixture of distributions. There are several components contributing to the OWTT in routers, i.e., processing delay, queueing delay and service time. The obtained results have shown that, e.g., the processing delay in a router can be well modeled with the Normal distribution, and the queueing delay is well modeled with a mixture of Normal distribution for the body probability mass and Weibull distribution for the tail probability mass. Furthermore, OWTT has several component delays and it has been observed that the component delay distribution that is most dominant and heavy-tailed has a decisive influence on OWTT

On the Performance of Overlay Multicast Networks

The paper reports on a performance study of several Application Layer Multicast (ALM) protocols. Three categories of overlay multicast networks are investigated, namely Application Level Multicast Infrastructure (ALMI), Narada and NICE is the Internet Cooperative Environment (NICE). The performance of the overlay multicast protocols is evaluated with reference to a set of performance metrics that capture both application and network level performance. The study focuses on the control overhead induced by the protocols under study. This further relates to the scalability of the protocol with increasing number of multicast participants. In order to get a better assessment of the operation of these protocols in "real-life"-like conditions, we implemented in our simulations a heavy-tailed delay at the network level and churn behavior of the overlay nodes. Our performance study contributes to a deeper understanding and better assessment of the requirements for such protocols targeted at, e.g., media streaming

Implementation of Application Layer Multicast in OverSim

This paper presents an overview of the implementation of Application Layer Multicast (ALM) in OverSim, a simulation framework designed specifically for simulating overlay networks. OverSim builds upon the OMNeT++ discrete event simulator. In addition, the paper presents guidelines for further research work based on reliable and Quality of Service (QoS)-aware multicast overlay networks. This research work is part of a bigger research project, called "Routing in Overlay Networks (ROVER)" which is focused on unicast and multicast routing in overlay networks with QoS guarantees and congestion control facilities on top of existing and future Peer-to-Peer (P2P) networks

Measurement of One-Way Transit Time in IP Routers

The main goals of the tutorial are towards an understanding of the delay process in best-effort Internet for both non-congested and congested networks. A novel measurement system is reported for delay measurements in IP routers, which follows specifications of the IETF RFC 2679. The system is using both passive measurements and active probing and offers the possibility to measure and analyze different delay components of a router, e.g., packet processing delay, packet transmission time and queueing delay at the output link. Dedicated application-layer software is used to generate UDP traffic with TCP-like characteristics. Pareto traffic models are used to generate self-similar traffic in the link. The reported results are in form of several important statistics regarding processing and queueing delays of a router, router delay for a single data flow, router delay for more data flows as well as end-to-end delay for a chain of routers. We confirm results reported earlier about the fact that the delay in IP routers is generally influenced by traffic characteristics, link conditions and, at some extent, details in hardware implementation and different IOS releases. The delay in IP routers may also occasionally show extreme values, which are due to improper functioning of the routers. Furthermore, new results have been obtained that indicate that the delay in IP routers shows heavy-tailed characteristics, which can be well modeled with the help of three distributions, either in the form of single distribution or as a mixture of two distributions. There are several components contributing to the One-Way Transit Time (OWTT) in routers, i.e., processing delay, queueing delay and service time. Our results have shown that, e.g., the processing delay in a router can be modeled with the Normal or skewed Normal distribution, and the queueing delay is well modeled with a mixture of Normal distribution for the body probability mass and of Weibull distribution for the tail probability mass. It has been also observed that One-Way Transit Time (OWTT) is well modeled with the generalized Pareto distribution. Furthermore, OWTT has several component delays and it has been observed that the component delay distribution that is most dominant and heavy-tailed has a decisive influence on OWTT. To the best of our knowledge, this is the first time we understand the distributional properties of the delay process in an IP router

On Kleinrock's Independence Assumption

The paper is about analyzing the delay performance in a chain of IP routers, with focus on queueing delay and the correlations existing in a tandem queueing system. Leonard Kleinrock independence assumption is particularly considered, based on which the correlations can be ignored, and the effect on delay performance is negligible, under specific assumptions like for instance Poisson arrival processes, Exponential distribution for packet lengths, sufficient traffic mixing and moderate-to-heavy traffic loads. Furthermore, the paper is reporting on results obtained in experiments done at the Blekinge Institute of Technology in Karlskrona, Sweden, on measurements, modeling and analysis of delay in a chain of IP routers. Particular focus is given to validating the Kleinrock independence assumption regarding the effect of correlations in a tandem queueing system. Our results show that this assumption is not valid in our experiments, and this is particularly observed in the end-to-end delay distribution