Real-Time Traffic Transmissions Over the Internet

Multimedia applications require the transmission of real-time streams over a network. These streams often exhibit variable bandwidth requirements, and require high bandwidths and guarantees from the network. This creates problems when such streams are delivered over the Internet. To solve these problems, recently, a small set of differentiated services has been introduced. Among these, Premium Service is suitable for transmitting real-time stored stream (full knowledge of the stream characteristics). It uses a bandwidth allocation mechanism (BAM) based on the stream peak rate. Due to the variable bandwidth requirement, the peak rate BAM can waste large amount of bandwidth. In this paper we propose a new BAM that uses less bandwidth than the peak rate BAM, while providing the same service. Our BAM does not affect the real-time stream quality of service (QoS) and does not require any modification to the Premium Service Architecture. We also introduce several frame dropping mechanisms that further reduce bandwidth consumption subject to a QoS constraint when coupled with the above BAM. The proposed BAM and the dropping mechanisms are evaluated using Motion JPEG and MPEG videos and are shown to be effective in reducing bandwidth requirements. Further, since VCR operations are very useful in video streaming, we propose a mechanism that introduces these operations in our BAM. Through simulations we show the effectiveness of this mechanism.