A self-adjusting rate adaptation scheme with good fairness and smoothness properties

A novel feedback-based rate adaptation scheme is introduced and investigated in this paper. Its main innovative characteristic is the modulation of the rate increment by the distance between a flow's present rate and an assumed targeted maximum rate as dictated by the associated application. The previous along with the shaping of the rate decrement by the reported flow's losses are responsible for a dynamic and self-adjusting behavior that is shown to improve convergence to fairness, the oscillatory behavior of the rate and the induced packet losses when compared with the basic Additive Increase Multiplicative Decrease (AI/MD) scheme. Numerical results illustrate the good properties and intrinsic advantages of the proposed scheme both under the considered modeling assumptions, as well as under more real networking conditions by employing the ns-2 simulator. A brief comparison of the proposed scheme with the TCP-compatible schemes TFRC, IIAD and the non-AI/MD schemes AIPD, LIMPD, is included as well. Because of the aforementioned induced behavior and assumed flow's characteristics (min and max rates), the proposed congestion control scheme seems to be appropriate for regulating the rate of streaming applications. © 2004 Elsevier B.V. All rights reserved

A Self-adjusting Rate Adaptation Scheme with Good Fairness and Smoothness Properties

A novel feedback-based rate adaptation scheme is introduced and investigated in this paper. Its main innovative characteristic is the modulation of the rate increment by the distance between a flow’s present rate and an assumed targeted maximum rate as dictated by the associated application. The previous along with the shaping of the rate decrement by the reported flow’s losses are responsible for a dynamic and self-adjusting behavior that is shown to improve convergence to fairness, the oscillatory behavior of the rate and the induced packet losses when compared with the basic Additive Increase Multiplicative Decrease (AI/MD) scheme. Numerical results illustrate the good properties and intrinsic advantages of the proposed scheme both under the considered modeling assumptions, as well as under more real networking conditions by employing the ns-2 simulator. A brief comparison of the proposed scheme with the TCP-compatible schemes TFRC, IIAD and the non-AI/MD schemes AIPD, LIMPD, is included as well. Because of the aforementioned induced behavior and assumed flow’s characteristics (min and max rates), the proposed congestion control scheme seems to be appropriate for regulating the rate of streaming applications

Adaptive delay-constrained internet media transport

Reliable transport layer Internet protocols do not satisfy the requirements of packetized, real-time multimedia streams. The available thesis motivates and defines predictable reliability as a novel, capacity-approaching transport paradigm, supporting an application-specific level of reliability under a strict delay constraint. This paradigm is being implemented into a new protocol design -- the Predictably Reliable Real-time Transport protocol (PRRT). In order to predictably achieve the desired level of reliability, proactive and reactive error control must be optimized under the application\u27s delay constraint. Hence, predictably reliable error control relies on stochastic modeling of the protocol response to the modeled packet loss behavior of the network path. The result of the joined modeling is periodically evaluated by a reliability control policy that validates the protocol configuration under the application constraints and under consideration of the available network bandwidth. The adaptation of the protocol parameters is formulated into a combinatorial optimization problem that is solved by a fast search algorithm incorporating explicit knowledge about the search space. Experimental evaluation of PRRT in real Internet scenarios demonstrates that predictably reliable transport meets the strict QoS constraints of high-quality, audio-visual streaming applications.Zuverlässige Internet-Protokolle auf Transport-Layer erfüllen nicht die Anforderungen paketierter Echtzeit-Multimediaströme. Die vorliegende Arbeit motiviert und definiert Predictable Reliability als ein neuartiges, kapazitäterreichendes Transport-Paradigma, das einen anwendungsspezifischen Grad an Zuverlässigkeit unter strikter Zeitbegrenzung unterstützt. Dieses Paradigma wird in ein neues Protokoll-Design implementiert -- das Predictably Reliable Real-time Transport Protokoll (PRRT). Um prädizierbar einen gewünschten Grad an Zuverlässigkeit zu erreichen, müssen proaktive und reaktive Maßnahmen zum Fehlerschutz unter der Zeitbegrenzung der Anwendung optimiert werden. Daher beruht Fehlerschutz mit Predictable Reliability auf der stochastischen Modellierung des Protokoll-Verhaltens unter modelliertem Paketverlust-Verhalten des Netzwerkpfades. Das Ergebnis der kombinierten Modellierung wird periodisch durch eine Reliability Control Strategie ausgewertet, die die Konfiguration des Protokolls unter den Begrenzungen der Anwendung und unter Berücksichtigung der verfügbaren Netzwerkbandbreite validiert. Die Adaption der Protokoll-Parameter wird durch ein kombinatorisches Optimierungsproblem formuliert, welches von einem schnellen Suchalgorithmus gelöst wird, der explizites Wissen über den Suchraum einbezieht. Experimentelle Auswertung von PRRT in realen Internet-Szenarien demonstriert, dass Transport mit Predictable Reliability die strikten Auflagen hochqualitativer, audiovisueller Streaming-Anwendungen erfüllt