Definition, Implementation and Testing of an XML-based Packet Description Language for Traffic Analysis in a SpaceWire Communication

The on-board communication standard adopted in current generation space missions of the European Space Agency (ESA), and many other agencies as well, is SpaceWire (SpW). In a SpW network, data are exchanged as well-formed packets, which structure offers low packet overhead and allows developers to easily tailor their implementation for SpW applications. The flexible structure of SpW packets has allowed the definition of several SpW protocols, such as the Remote Memory Access Protocol (RMAP), that can be used in specific SpW applications. This paper presents the definition of the SpW Packet Description Language (SpW PDL), based on the eXtensible Markup Language (XML), to provide SpW developers with an instrument to easily define SpW packets, in both human-readable and machine-readable manner, aiding in the development of packet-format independent SpW applications. The SpW PDL allows the developer to simply define a single, or a set of, SpW packet structures by means of an XML file, adhering to a specifically designed XML schema. Such XML file can then be used by specific software for SpW-based systems. To verify the compliance with the SpW standard, it is critical to dispose of a set of tools and instrumentation to test SpW applications and SpW-based systems. Such equipment is part of the Electrical Ground Support Equipment (EGSE). In this scope, the SpW PDL described in this paper has been integrated into the SpaceART SpaceWire Sniffer, a user-friendly SpW link analyzer, designed to unobtrusively test and verify SpW communication between two SpW nodes. To prove the potential of the provided solution, a test-case in which SpW PDL is exploited for SpW traffic analysis is presented, demonstrating the benefits of the adoption of the SpW PDL in SpW systems test and verification. The present work comprises five sections: at first, an introduction about EGSE, SpW Standard, and SpW packet format is given, introducing also the RMAP SpW protocol. Then the SpW PDL is presented, describing its definition and implementation. Later on, the SpaceART SpW Sniffer is described followed by a use-case scenario in which it is used to analyse SpW traffic, exploiting the SpW PDL. In conclusion, the result of the use of such technologies is given.