An Investigation into the Effects of GEO Satellite Environments upon H.323-based Voice over IP

The work presented in this report was performed within the IMMSAT project, a project carried out during Q2-Q4 2000 by Norsk Regnesentral [21] and Nera SatCom AS [23]. IMMSAT comprised both a theoretical and an empirical study of technical aspects concerning “Internet Protocol based MultiMedia Services over a Satellite Network”. Specifically, the project focussed upon technical aspects involved in the delivery of Voice over IP (VoIP), Video over IP, and Fax over IP within a GEO satellite-based environment. Originally, the empirical work within IMMSAT intended to look into the effects of satellite characteristics such as latency, jitter, packet loss and bit error rate (BER) upon all three XoIP services. Due to limited feasibility and time for testing, however, prototype testing was focused upon an H.323based VoIP service. The primary objective during prototype testing was to validate, while simulating GEO satellite network characteristics, that H.323 protocols and an H.323-based VoIP service could successfully be used in a GEO satellite-based IP network. The primary types of VoIP tests carried out during prototype testing were call establishment and audio voice quality. For these test types, the investigation proceeded with an effort to identify the parametric limits for latency, jitter, and packet loss/BER where: • the H.323-based protocols could no longer provide an acceptable service for establishing VoIP calls (i.e., where call establishment becomes severely impaired and/or ceases to function in a timely manner) and • the VoIP audio voice quality becomes unacceptable (i.e., where audio voice quality degrades such that usability of the service is severely and/or wholly impaired). This document presents the outcomes of prototype testing, along with an accompanying analysis. Conclusions are also drawn about the robustness and quality for H.323-based VoIP services via satellite. Emneord/