In this master's thesis I deal with modelling and simulating of multicast routing protocol PIM Sparse Mode in OMNeT++. I also describe basic information about multicast, protocol PIM-SM, its configuration and multicast data streams visualization in computer networks. The thesis is especially focused on design and implementation of PIM-SM in OMNeT++ and extension of ANSAINET library.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / The NASA Communications (Nascom) Division has been directed to deploy Internet Protocol (IP) based technology for the ground segments of all present and future spaceflight telemetry networks. The Nascom network supports all NASA spaceflight telemetry, command and status requirements, from sounding rockets and balloons to the Hubble Space Telescope and the Space Shuttle. This paper discusses the challenges of transitioning a 35 year old, custom engineered, worldwide legacy telemetry network to IP, and the resulting, new NASA IP Operational Network for ground transport of spacecraft telemetry and command.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Range Instrumentation and Control System (RICS) is a PC-based multi-platform data acquisition and display system utilizing CORBA and Multicast UDP in a client/server architecture. Its main purpose is to collect time-space position information (TSPI) from one or more remote radar sites and distribute it in real-time across a wide area network (WAN). This paper describes the collection of MS Windows-based software applications that are designed to control and monitor data acquisition in real-time from a remote console.

The majority of ATM switches that have been proposed only support unicast (point-to-point) connections. Those supporting multicast (point-to-multipoint) connections tend to perform poorly, with acceptable multicast performance only achievable using an excessive amount of hardware. Because of the growing importance of multicast traffic, there is the demand for multicast switch designs which offer both low hardware complexity and high performance. This research investigates a class of multicast ATM switches called recycling switches which can satisfy both requirements. Recycling switch performance is studied using a simulated network model. The major performance parameters measured are the loss rate, mean delay, and delay variance of cells crossing through the switch under uniform and bursty traffic patterns. The reason recycling is not more widely used in multicast switches is the perception that it can lead to some multicast cells receiving lower quality of service than others. This research demonstrates a new priority-based approach to designing recycling multicast ATM switches which addresses this problem while maintaining low complexity and excellent scalability. / Masters Thesis

La thèse s'intéresse au problème de la gestion de la fiabilité dans les réseaux par satellite basés sur la norme de diffusion DVB-S, pour des applications multipoints. En raison de possibles fluctuations des conditions de propagation, le service offert par le lien satellite n'est pas garanti. Le cas échéant, il doit être complété par un service de niveau transport, contraint à limiter l'utilisation de la voie de retour en raison du nombre potentiellement élevé de récepteurs. La première problématique étudiée concerne les concepts à envisager pour concevoir une architecture protocolaire appropriée. L'architecture prévoit de reconsidérer l'utilisation des contrôles d'intégrité des données, et de renforcer la fiabilité sur les en-têtes des différentes couches protocolaires. Ce mécanisme est appelé Multi Protocol Header Protection. La réalisation de ces concepts est également étudiée. Elle est proposée dans le cadre de la méthode Ultra Lightweight Encapsulation permettant la livraison de datagrammes IP par les réseaux DVB. L'exploitation de l'architecture pour deux services de fiabilité est ensuite discutée au niveau des protocoles de transport. Le premier service, appelé fiabilité binaire non contrôlée, peut être offert pour des applications tolérantes aux erreurs binaires. Des simulations démontrent l'intérêt de l'architecture pour ce service. Pour un service de fiabilité totale, l'élaboration d'un procédé de fiabilisation adapté à l'architecture est étudiée. Le procédé fait intervenir un algorithme de décodage FEC adapté. L'évaluation globale de l'approche estime que pour un service identique, 5 à 30 fois moins de données peuvent être économisées comparativement à une architecture conventionnelle.

<p>In recent years, with the fast development of resource capability of both the Internet and personal computers, multimedia applications like video-on-demand (VOD) streaming have gained dramatic growth and been shown to be potential killer applications in the current and next-generation Internet. Scalable deployment of these applications has become a hot problem area due to the potentially high server and network bandwidth required in these systems.</p><p>The conventional approach in a VOD streaming system dedicates a media stream for each client request, which is not scalable in a wide-area delivery system serving potentially very large numbers of clients. Recently, various efficient delivery techniques have been proposed to improve the scalability of VOD delivery systems. One approach is to use a scalable delivery protocol based on multicast, such as periodic broadcast or stream merging. These protocols have been mostly developed for single-server based systems and attempt to have each media stream serve as many clients as possible, so as to minimize the required server and network bandwidth. However, the performance improvements possible with techniques that deliver all streams from a single server are limited, especially regarding the required network bandwidth. Another approach is based on proxy caching and content replication, such as in content delivery networks (CDN). Although this approach is able to effectively distribute load across multiple CDN servers, the cost of this approach may be high.</p><p>With the focus on further improving the system efficiency regarding the server and network bandwidth requirement, a new scalable streaming protocol is developed in this work. It adapts a previously proposed technique called hierarchical multicast stream merging (HMSM) to use a peer-to-peer delivery approach. To be more efficient in media delivery, the conventional early merging policy associated with HMSM is extended to be compatible with the peer-to-peer environment, and various peer selection policies are designed for initiation of media streams. The impact of limited peer resource capability is also studied in this work. In the performance study, a number of simulation experiments are conducted to evaluate the performance of the new protocol and various design policies, and promising results are reported.

För att installera flera operativsystem samtidigt finns det olika verktyg avsedda för att underlätta denna process. Det finns både kommersiella- och gratisalternativ ute på marknaden. En av de ledande kommersiella replikeringsmjukvarorna är Symantec Ghost. I detta arbete jämförs Symantec Ghosts mot Free open-source ghost (FOG) för att mäta användbarheten med avseende på kritiska attribut. Kritiska attribut är baserade på utförandet av en fullständig replikeringsprocess samt hur en användare upplever hanteringen av mjukvaran. Resultaten består av både kvalitativa och kvantitativa resultat som sammanställs i en jämförelsematris som presenterar för- och nackdelar med mjukvarorna. Resultaten visar att användbarheten är relativt likvärdig men att FOG presterar lite bättre än Symantec Ghost.

<p>In recent years, with the fast development of resource capability of both the Internet and personal computers, multimedia applications like video-on-demand (VOD) streaming have gained dramatic growth and been shown to be potential killer applications in the current and next-generation Internet. Scalable deployment of these applications has become a hot problem area due to the potentially high server and network bandwidth required in these systems.</p><p>The conventional approach in a VOD streaming system dedicates a media stream for each client request, which is not scalable in a wide-area delivery system serving potentially very large numbers of clients. Recently, various efficient delivery techniques have been proposed to improve the scalability of VOD delivery systems. One approach is to use a scalable delivery protocol based on multicast, such as periodic broadcast or stream merging. These protocols have been mostly developed for single-server based systems and attempt to have each media stream serve as many clients as possible, so as to minimize the required server and network bandwidth. However, the performance improvements possible with techniques that deliver all streams from a single server are limited, especially regarding the required network bandwidth. Another approach is based on proxy caching and content replication, such as in content delivery networks (CDN). Although this approach is able to effectively distribute load across multiple CDN servers, the cost of this approach may be high.</p><p>With the focus on further improving the system efficiency regarding the server and network bandwidth requirement, a new scalable streaming protocol is developed in this work. It adapts a previously proposed technique called hierarchical multicast stream merging (HMSM) to use a peer-to-peer delivery approach. To be more efficient in media delivery, the conventional early merging policy associated with HMSM is extended to be compatible with the peer-to-peer environment, and various peer selection policies are designed for initiation of media streams. The impact of limited peer resource capability is also studied in this work. In the performance study, a number of simulation experiments are conducted to evaluate the performance of the new protocol and various design policies, and promising results are reported.

Multicast is an effective technology to save network bandwidth while transmitting data packets in WiFi networks. However, it lacks of a mechanism to recover lost packets. When interference or congestion occurs in wireless networks, the receiver cannot receive complete data. In this Thesis, we propose a multicast retransmission mechanism which integrates NACK in WiFi networks. Also, the sender can dynamically adjust retransmission parameters according to the network status reported from the receiver. To demonstrate our proposed mechanism, three parts are implemented on the Linux platform. First, the RTP header is added in each packet and the buffer is maintained in both the sender and the receiver before the sender can transmit data. Second, a module is installed in the wireless card driver to examine the CRC errors caused by interference. Then the sender can be notified by NACK such that the sender may know the reasons of packet loss and the numbers of dropped packets. Third, the sender utilizes RTCP to calculate RTT and derive RTO. The retransmission time is calculated based on RTO, interferences, and congestion. Finally, our measurement results show that the sender can effectively use multicast retransmission according to various background traffics. Besides, the number of retransmitted packets can be significantly reduced.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme (Fakultaet fuer Informatik) der TU Chemnitz. Workshop-Thema: Infrastruktur der ¨Digitalen Universitaet¨ Der Vortrag gibt einen Überblick über den aktuellen Stand (April 2000) von IP-Multicast im Campusnetz und die MBONE-Anbindung der TU Chemnitz.