QRP08-2: A Method of User-Level QoS Guarantee by Session Control in Audio-Video Transmission over IP Networks

This paper proposes a session control method which provides a mechanism to achieve desirable user-level QoS (i.e., perceptual QoS) of audio-video transmission over IP networks. The proposed method, which is referred to as GPSQ (Guarantee of Psychologically Scaled Quality), utilizes a user-level QoS parameter of the interval scale in the psychometric analysis. GPSQ involves four kinds of components: media terminals, a SIP server, a QoS manager and bandwidth-controllable routers. From the media terminals, the SIP server obtains the information for this control, which is further delivered to the QoS manager. The QoS manager keeps a database of representative regression lines which express user-level QoS as a function of guaranteed bandwidth of audio and that of video. Using the regression line, the QoS manager calculates necessary guaranteed bandwidth according to user-level QoS specified by the user. Then, the QoS manager sets up routers to guarantee the calculated bandwidth. We implemented GPSQ in a simple experimental network and confirmed its effectiveness.