STANAG 4856 command and control to simulation (C2SIM) interoperability

What it is

STANAG 4856 is a NATO Standardization Agreement, currently Edition 1, dated 15 March 2023. It is not a technical specification. It is the agreement by which NATO nations commit to implement two standards published by the Simulation Interoperability Standards Organization (SISO): SISO-STD-019, the standard for command and control systems to simulation systems interoperation, and SISO-STD-020, its land operations extension. The technical detail, the data exchange rules a reader usually wants, lives inside those two SISO standards, not inside this six-page cover. Read on its own, STANAG 4856 requires almost nothing of a supplier directly. Its obligations run to nations, and it reaches a contractor only indirectly, once a nation has implemented it and a contract or tender names SISO-STD-019 or SISO-STD-020.

Who it binds, and how

STANAG 4856 is explicit that it binds nations rather than organisations. It "is effective upon receipt for use by the participating nations and NATO bodies." Its letter of promulgation describes the enclosed agreement as one "which has been ratified by member nations, as reflected in the NATO Standardization Document Database (NSDD), is promulgated herewith." Ratification and implementation are separate steps: nations that "have not already done so" are invited to "advise the NSO of their intention regarding its ratification and implementation." So "is STANAG 4856 mandatory" has no single answer. It depends on whether a given nation has ratified and implemented it, and, for a supplier, on whether a specific contract invokes SISO-STD-019 or SISO-STD-020 as a result.

What the agreement actually commits nations to

The stated aim is "to respond to the following interoperability requirements": extending "consultation, command and control (C3)" to "act together coherently, effectively and efficiently to exchange data with simulations, in order to achieve the Alliance's objectives"; doing so "by defining a standard way to express and exchange command and control (C2) information providing tasking to simulation systems and feedback reports from those systems, along with information required for synchronized initialization and operation of those simulation systems"; enabling coalitions to "train as you fight" through "automated linkage to multiple participating simulation systems"; and enabling other C3 activities "such as mission rehearsal and decision support to make plug-and-play use of multiple participating simulation systems." Under "Agreement," participating nations "agree to implement the following standards": SISO-STD-019 and SISO-STD-020. None of this is written as a duty on a supplier directly; it is a duty on the nation, and on the systems that nation fields.

A cover agreement, not the interoperability specification

A reader who only has STANAG 4856 in hand does not yet have the interoperability specification itself. SISO-STD-019 and SISO-STD-020 hold that. This document names two further related publications for context, SISO-GUIDE-010 ("Guide for Command and Control Systems - Simulation Systems Interoperation") and STANAG 5524, which covers ADatP-34, the NATO Interoperability Standards and Profiles. Neither is a prerequisite in a supplier's own sense; they show where SISO-STD-019 and SISO-STD-020 sit among NATO's other interoperability documents. STANAG 4856 supersedes no earlier document: "This STANAG does not supersede any document."

Implementation and review

STANAG 4856 is implemented "when it has issued instructions that all relevant future systems, which interface to NATO and other national systems when engaged in NATO operations, will conform to the specifications detailed in the above-cited SISO standards." That conformance "requires use of data model ontologies, and their transformation to Extensible Markup Language (XML) schema for data exchange, as defined by the cited SISO standards." The NATO Effective Date is stated as "Not applicable," and national ratification and implementation details are reported through the electronic reporting tool and recorded in the NSDD. The STANAG "is to be reviewed in accordance with AAP-03," with the result recorded in the NSDD, and the agreement is supervised under NATO's Modelling and Simulation Group.

What it does not cover

STANAG 4856 names no supplier obligation directly: every duty in the text runs to "nations" or "NATO bodies," never to a contractor or manufacturer. It also names no assessment or certification scheme of any kind. The only stated check is that the agreement itself is reviewed periodically against AAP-03, not that a system, a supplier or an organisation is certified against it. What SISO-STD-019 and SISO-STD-020 actually require of a C2 or simulation system is not described here beyond their titles.

Standards it references

• STANAG 5524Background