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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).
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.
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.
Policy based resource management for QoS aware applications in heterogeneous network environments
(2007)
Dynamic configuration and adaptation of resources for QoS-aware applications in heterogeneous access network environment (UMTS, WIMAX, WLAN DVB-T, DVB-H) using automated tools is a challenge today. The focus of this paper is a toolkit for intelligent management of resource allocation in heterogeneous network infrastructures based on policies of different actors (network operator, service providers and users). Policy based management of resources for QoS-aware applications (Video-on-Demand, Mobile TV) dependent on network capabilities, context learning and preferences of the policy actors is proposed, which enhances the current state-of-the-art and IETF standardisation. The policy management toolkit includes components for policy specification, adaptation and enforcement, which are interacting using policy repository. The design allows the automated resource adaptation for QoS based applications based on context information and hierarchical dependencies of policy actors. A learning component is integrated in order to discover the context considering measurement and monitoring data. The policy management tookit is discussed, emphasising on ontology driven policy repository design, context learning and flexible scenario-oriented management interfaces for policy specifications.
Influence of priorities on the performance of a fast packet switch in the case of bursty traffic
(1992)
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.
UTRAN Internet Access
(1999)
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.