The SpaceWire standard defines a network designed for handling payload data and control information onboard a spacecraft. Among the goals of SpaceWire are re-usability and reliability. The use of network protocols on top of SpaceWire is expected to enhance the already rich re-usability and reliability characteristics of SpaceWire. The Space Systems Research Group at the University of Dundee have developed software to allow data to be sent over SpaceWire using standard network protocols such as TCP/IP, as part of a program of work looking at network protocols for SpaceWire. This paper describes network protocols and their relationship to SpaceWire, introduces software written to allow network protocols +to be layered on to SpaceWire, describ...