An applied research study for the provision of a QoS-oriented environment for voice and video services over satellite networks

Abstract

The aim of this paper is to present a network solution to provide Quality of Service (QoS) guaranteed voice and video services over a satellite test-bed based on the TCP/IP protocol suite, oriented to distance learning. The scope of the solutions proposed is a small private satellite network where specific services (e.g. tele-education) are offered to the users. The paper describes the main operating steps followed to perform the tests. The target service requirements are identified and the configuration of devices and protocols are described in detail. The Integrated Services approach is utilized along with three different scheduling mechanisms at IP layer. A proper routing protocol to support multicast is used. The work is a part of a project called ‘Integration of Multimedia Services over Heterogeneous Satellite Networks’, which has been developed by the Italian National Consortium of Telecommunications (CNIT) and funded by the Italian Space Agency (ASI). The test-bed is composed of two remote sites, connected through a satellite link at 2 Mbits/s and by one site, where no satellite device is available, connected by using ISDN. The results reported allow to test the application of bandwidth reservation strategies originally studied for a terrestrial environment and to measure the consequent performance improvement. The use of both subjective metrics as mean opinion score (MOS) and objective metrics, as audio/video packet loss and average bit rate, to perform the investigation, allow mapping the measure of P-QoS (Perceived-Quality of Service) with quantities uninfluenced by personal opinions. The configurations used represent the result of an applied research project and provide an operative solution, inclusive of technical details, to guarantee high quality of service for audio/video applications.