STP-ISS transport protocol for spacecraft on-board networks

SpaceWire is a data-handling network for spacecraft which combines simple, low-cost implementation, with high performance and architectural flexibility. SpaceWire is intended for data-handling applications but does not address such aspects of quality of service as robustness, determinism and durability that are essential requirements. Nowadays there is a number of transport protocols intended to operate over SpaceWire. They are: RMAP, CCSDS PTP, STUP, JRDDP and STP. Each of them is designed to solve its particular tasks. However, there is no SpaceWire oriented transport protocol providing reliability, guaranteed services and scheduling. The paper presents the new Transport protocol STP-ISS for SpaceWire networks. Firstly, it gives an overview and analysis of SpaceWire oriented transport protocols, then, considers general requirements for the Transport protocol to operate over the SpaceWire network technology. Finally, we describe the current status of the STP-ISS specification and consider the future evolution of the standard.