Preparing for transition: Accommodation of mixed data communication equipage for a harmonized future

The Aeronautical Telecommunications Network using the Internet Protocol Suite (ATN/IPS) continues to progress in standardization and maturity towards becoming an implemented reality, and is a recognized end-state goal for United States (US) — European Union (EU) Data Communication Harmonization. However, the transition from existing data communications to ATN/IPS creates challenges for handling multiple applications and network protocols. Potentially, some form of accommodation of both existing Aeronautical Telecommunications Network using the Open System Interconnection (ATN/OSI) and the Aircraft Communication Addressing and Reporting System (ACARS) will be necessary to allow interoperability to occur on the network level as well as at the application level, considering Future Air Navigation System 1/A (FANS-1/A), Baseline 1 (B1), and Baseline 2 (B2) applications. Changing equipage on aircraft is expensive and time consuming, considering factors such as the appropriate time to make a change to the aircraft given its maintenance schedules, revenue flight load, etc., in addition to the costs for development, certification and installation of equipage. Air Navigation Service Providers (ANSPs) should also not be required to continually upgrade ground systems or implement duplicate networks to deal with these complexities. Therefore an approach is needed that would allow the initial introduction of ATN/IPS while preserving backwards compatibility for aircraft equipped with other technologies, ensuring that airline and ANSP investments are preserved as much as possible while providing a transition path to the envisaged end state. In order to enable that transition, depending on the final architecture and configuration, network diversity could be accommodated on the aircraft, on the ground, or a combination of both. As discussed in various forums such as the Airlines Electronic Engineering Committee (AEEC), it is unlikely that a triple stack (i.e., ACARS, ATN/OSI, and ATN/IPS) will be implemented in the aircraft given complexity, certification, and cost factors. Therefore, much of the accommodation would have to be done on the ground, potentially using a protocol gateway. This gateway would accommodate a both FANS-1/A and B1/B2 applications, meaning a combination of ACARS to ATN/IPS and ATN/OSI to ATN/IPS translation capabilities (and vice versa). This paper discusses efforts to further investigate this gateway concept, the types of capabilities that are needed, potential architectures, advantages and disadvantages, and prototype activities. Finally proposed future work that is necessary to reach Data Communication Harmonization goals and conclusions will be given.