Deploying IP Telephony Over Satellite Links

IP telephony is one of the fastest growing technologies. It is based on the TCP/IP protocol suite. However to provide the same services and service qualities like legacy telephony networks, special care has to be taken for the IP network design. The TCP/IP protocol suite is also increasingly used for satellite communications, which offers wide-area broadband connections to any point within the satellite´s footprint. In order to implement voice over IP (VoIP) over satellite links, the network design has additionally to consider the physical characteristics of the link. This paper presents the implementation of VoIP over satellite links, which are also used in parallel for data transfer and video conferencing. Quality of service (QoS) is thereby the key technology to enable the combination of data and voice services. It is investigated which level of service quality can be achieved both on the LAN and on the satellite link by using QoS mechanisms available in off-the-shelf routers and switches. This paper includes a presentation of the basic technologies, the architectural design and an in-depth discussion of the configuration used. Finally, the resulting service quality is discussed