ATM over VSAT networks using traditional bent-pipe or on-board processing satellites

Abstract

In this paper two VSA T satellite network architectures are proposed to offer access to the B-ISDN and accommodate ATM service needs in an integrated manner, while achieving maximum bandwidth utilisation of the satellite. The first architecture uses a traditional 'bent pipe' repeater satellite. The need for optimization of the channel capacity allocation scheme is discussed, using a preliminary performance analysis for a Dynamic Reservation TDMA system which takes advantage of the flexibility and the statistical multiplexing capabilities of ATM and supports various VBR and CBR services. Some bottlenecks, introduced by the satellite link, in the performance of protocols such as TCPIIP are highlighted. The second architecture uses an OBP satellite with spot beams and cell-switching capabilities. A novel approach, in which statistical multiplexing is performed on-board the satellite, is suggested and results show that a much better satellite bandwidth utilization can be achieved. In this architecture, smaller earth terminals can be used without complex dynamic reservation protocols, but at the cost of a more complex satellite payload.