Cyber Effects simulation, Data Link, Distributed Simulation, Interoperability, LVC, MILS, Security, TDL
A Tactical Data Link (TDL) concerns both processes and information exchange, and can be modelled at different levels of realism, depending on the purpose of the simulation environment. For instance, for purpose of Training and Exercise (T&E) with Computer Aided Exercises (CAX), a tactical data link can be modelled at a low level of realism. The processes and information exchange do not have to be performed in real time. Also, at this level it is sufficient to model a data link at a logical level, whereby the information can be supplemented with additional information for the purpose of the analysis. At the other end of the spectrum is the test and evaluation of live systems and live data flows. For this purpose, a tactical data link must be modelled with a much higher level of realism. Information exchange is (hard) real-time and data link information cannot be supplemented with information for, for instance, performance purposes. Special reconstruction tools are used to review and analyse the recorded (live) data stream. In the middle of this spectrum is training, where in many cases a tactical data link can be modelled at a logical level, but still at a higher level of realism than within the CAX example above. In practice gateway solutions are used to connect training systems and / or live systems to a common "backbone" for the exchange of simulation data and data link information.
Although there are simulation standards for data link modelling, these simulation standards usually follow the standards for live TDL data streams (such as SISO-STD-002-2006 for Link 16 over HLA). In the Link 16 example, Link 16 messages are exchanged as data in "binary large object models" (BLOBs) wrapped in a (HLA) simulation message and the exchange of simulation messages reflects the facets and complexity of the real TDL information exchange. When using a standard to simulate a real TDL, analysis tools and training systems must understand the complexity of the real tactical data link, and exchange and format messages conform the TDL standard. For non-real time analysis and simulation this complexity may not always be required. In addition, since messages are exchanged as a "binary object data" – reflecting the actual live binary format rather than structured and “open” HLA Federation Object Model (FOM) messages – it is not possible to develop generic (data stream agnostic) tools such as HLA simulation gateways and HLA security guards, or generic tools to inject cyber effects at the tactical level. These tools now need to be aware of the binary object data they exchange and implement the TDL standard to encode/decode messages in order to perform for example filter functions.
A generic TDL Federation Object Model (FOM) that models several tactical data links at a logical level may alleviate the complexity of using a tactical datalink in a simulation environment. A generic TDL data model should be a readable format , defined in an open standard, and should support the most relevant/common TDL message exchanges. A generic TDL would enable the use of generic Secure Guard solutions that can inspect and modify generic TDL message fields and release or block message to domains with lower security classifications. Also, generic TDL messages create the possibility to introduce the effects of cyber attack on C2 systems that rely on data link messages.