Optimal Traffic Shaping with Deterministic Guarantees Using GPS Scheduling
IDMS/PROMS 2002 Proceedings of the Joint International Workshops on Interactive Distributed Multimedia Systems and Protocols for Multimedia Systems: Protocols and Systems for Interactive Distributed Multimedia
Client-centric usage environment adaptation using MPEG-21
Journal of Mobile Multimedia
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This paper studies bandwidth allocation schemes for the transmission of VBR video traffic with deterministic guarantees, i.e. no packets lost and no missed deadlines. Specifically, we propose and investigate a policy namedquasi-constant policy . A VBR encoder attempts to keep the quality of video output constant by varying the transmission rate (constant quality); on the other hand, with a quasi-constant policy the video quality transmission is reduced when congestion occurs. We assume that this reduction is obtained by exploiting source scalability. By characterizing the traffic of a source with a constraint function, we define the relationship between the amount of bandwidth assigned to a VBR source and the maximum delay the application may experience. By applying this relationship to long MPEG 2 traces (more than one hour) we show that the quasi-constant policy is a very promising direction for providing, in an efficient way, a deterministic QoS to VBR video traffic. Specifically, the results presented indicate that with the quasi-constant quality approach we can achieve a utilization greater than 50% with a deadline of one second with only eight reduced-quality frames out of 1000. On the other hand, previous works ([1, 2]) indicate that with a constant quality transmission, a 50% network utilization can be achieved only by tolerating a seven-second deadline.