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Filling the Pipe
(1995)
An Information on Demand teleservice that was developed at the German National Research Center for Information Technology (GMD) provides remote access to multimedia information consisting of audio, video, and text [jonas et al. 94]. It uses a bidirectional narrowband message link between the end user and the service provider, and a unidirectional broadband data link from the service provider to the end user. Since the IoD teleservice is used across a satellite connection (among others), it turned out to be necessary to implement an access protocol that is optimized for the access of real-time multimedia data across a long-delay high-bandwidth link, a long fat pipe [jacobsen et al. 92]. This paper introduces the MediaService Protocol (MSP) and describes a prototype implementation (version 0.6).
Influence of priorities on the performance of a fast packet switch in the case of bursty traffic
(1992)
The Internet Engineering Task Force (IETF) is currently working on the development of Differentiated Services (DiffServ). DiffServ seems to be a promising technology for next-generation IP networks supporting Quality-of-Services (QoS). Emerging applications such as IP telephony and time-critical business applications can benefit significantly from the DiffServ approach since the current Internet often can not provide the required QoS. This paper describes an implementation of Differentiated Services for Linux routers and end systems. The implementation is based on the Linux traffic control package and is, therefore, very flexible. It can be used in different network environments as first-hop, boundary or interior router for Differentiated Services. In addition to the implementation architecture, the paper describes performance results demonstrating the usefulness of the DiffServ concept in general and the implementation in particular.
ATM virtual studio services
(1996)
The term "virtual studio" refers to real-time 3D graphics systems used to render a virtual set in sync with live camera motion. As the camera pans and zooms, the virtual set is redrawn from the correct perspective. Using blue room techniques, actors in front of the real camera are then “placed in” the virtual set. Current virtual studio systems are centralized – the blue room, cameras, renderers etc. are located at a single site. However distributed configurations offer significant economies such as the sharing of expensive rendering equipment among many sites. This paper describes early expe- riences of the DVP1 project in the realization of a distributed virtual studio. In particular we de- scribe the first video production using a distributed virtual studio over ATM and make observations concerning network QOS requirements.
Three emerging technologies are combined in a setup that has been installed and tested at GMD - the German National Research Center for Information Technology: 1. Multimedia Telecooperation Applications; 2. ATM-based high-speed networks; 3. Satellite links. The results are promising: After some initial problems, the complete scenario is up and running, allowing the interconnection of local high-speed infrastructures in rural areas to a core network via satellite. This paper describes the R&D background and state- of-the-art that led us to this approach. It then describes the communication infrastructure and the application infra- structure of the setup, the problems we had and the solu- tions we found. Finally, our experiences are summarized, and an outlook is made for future implementations.
Multipoint data-communications is among the hot topics of communication research and development. A lot of studies and ideas have been presented, the vast majority focusing on a homogenous environment in terms of physical network, communication protocol stacks, coding schemes and/or service qualities. First straight-forward implementations –Steve Deering‘s IP multipoint on the MBone being the most popular one– already give an idea of the capabilities of a multipoint environment.
This paper presents the current stage of an IP-based architecture for heterogeneous environments, covering UMTS-like W-CDMA wireless access technology, wireless and wired LANs, that is being developed under the aegis of the IST Moby Dick project. This architecture treats all transmission capabilities as basic physical and data-link layers, and attempts to replace all higher-level tasks by IP-based strategies.
UTRAN Internet Access
(1999)
Reliable multicast transport services for content delivery in heterogeneous mobile environment
(2007)
For efficient deployment of new reliable multicast applications in heterogeneous mobile Internet environments, appropriate retransmission strategies are proposed. The focus is the minimization of the protocol overhead for reliable transport taking into account behaviour in mobile networks (oss and handover behaviour) and application requirements (such as carousel file transfer, one-to-many download and media streaming combined with recording). The proposed techniques are designed as building blocks for localized multicast error control supported by access routers. Considering IETF RMT standardization work, the discussed retransmission approaches can be used for flexible configuration of tree-based reliable multicast protocols in converged wired and wireless Internet environment. The implementation developed for the European project DAIDALOS [1] is based on Linux IPv6 environment. Simulations in ns2 focusing on the benefits of the proposed multicast retransmission schemes for particular application scenarios are presented.
With the rapid advances in multimedia content delivery technologies, there is an increasing challenge for efficient Quality of Service (QoS) based multicast transport in mobile Internet environment. This paper discusses architectural approach for provision of multicast services in heterogeneous mobile IPv6 environment using context transfer. Following issues of QoS based mobile multicast transport are addressed: - Application of context transfer between access routers for seamless handover of active multicast services; - Adaptation of multicast group management and routing designed for wired IPv6 infrastructures to heterogeneous mobile environment; - Candidate access router discovery and context aware user interfaces for optimised handover; - Reliable mobile multicast for content delivery supported by context transfer at access routers; - Distributed QoS management of multicast services in heterogeneous mobile environment. The work is part of the mobile architecture developed in the EU IST project DAIDALOS.
Bei der Datenübertragung im Internet ist es wünschenswert, daß unterschiedliche Datenpackete unterschiedlich behandelt werden können, damit für die zeitkritischen Anwendungen wie Internet-Telefonie die größere Priorität gewährleisten könnte. Erst dann kann ein Netzbetreiber seinen Kunden verschiedene Dienstqualitäten anbieten. Zwei grundsätzliche Mechanismen existieren, um dem Netzwerk solche Anforderungen mitzuteilen: explizit, indem vor der eigentlichen Datenübertragung Kotrollnachrichten ausgetauscht werden; implizit, indem jedes Datenpacket eine Kennzeichnung erhält. Der zweite, Differentiated Services(DS), Ansatz ist Thema dieses Referates. Bei DS wird jedem Packet den sogenannten DS-Codepoint (DSCP) im IP-Header zugewiesen, und dementsprechend erfährt ein Datenpaket eine bestimmte Behandlung durch einen DS-fähigen Router. Drei unterschiedliche Dienstklassen wurde bisher spezifiziert: Best-Effort entspricht dem derzeit im Internet verwendeten Mechanismus; Premium-Service entspricht einer virtuellen Mietleitung und soll eine rasche Weiterleitung von Paketen gewährleisten; Datenpakete mit Assured Forwarding Service (AFS) sollen besser behandelt werden als Best-Effort. Bei AFS wurden insgesamt drei Verlustklassen und vier Weiterleitungsklassen definiert. Es wird auch verschiedene Typ von DS-Router vorgestellt und diskutiert. Der praktische Einsatz erfolgte bisher immer in Laborumgebung (Uni Bern, Uni Karlsruhe, EPFL, Forschungszentrum NEC Research), größere Feldversuche stehen noch aus.