Considerations for a TSAT quality of service architecture

Transformation communications SATCOM (TSAT) is planned to be the satellite networking system for tactical and strategic warfighters of the future. TSAT is an integral part of the global information grid (GIG) architecture. The TSAT component of the architecture is used primarily in situations where user mobility, horizon limitations/obstructions or "last mile\´\´ economic considerations favor SATCOM use over the other media. TSAT is being designed as both an IP and circuit based core network that can support a multitude of applications, those in use presently as well as futuristic ones envisaged by the DoD. These applications or application categories have different QoS requirements as they relate to parameters such as throughput, delay jitter and packet error rates. A critical objective of the TSAT program is to provide such differentiated and guaranteed QoS based services. Designing an optimal TSAT QoS architecture is a challenging proposition for a number of reasons. These include constraints associated with the onboard IP router, the bandwidth on demand based radio channels, long propagation delays, delay jitter due to TDMA, the large number of terminal types (fixed and mobile), separation between red/black networks, and DoD specific preemption and priority requirements (MLPP). This paper describes approaches being evaluated to solving different facets of the TSAT QoS problem. These include techniques for service differentiation, dynamic QoS signaling, management of flows and call admission control.