Strategic-tactical interface prototype:

A new gateway for interoperable U.S./North Atlantic Treaty Organization/Partnership for Peace voice and data networks in U.S. European Command

by Roger Carpenter, John Jannis, Steve Sardi and Rob van Engelshoven

An emerging North Atlantic Treaty Organization interface has been successfully tested for use with U.S. mobile-subscriber equipment and triservice-tactical tactical switches. This interface, the strategic-tactical interface prototype, supports strategic-to-tactical and tactical-to-tactical interconnections between the United States and many allied and partner nations.

STIP doesn’t replace any existing interfaces but adds a new capability, conforming to a new digital strategic-tactical gateway NATO standards agreement (STANAG 4578). The gateway employs the Euro-Integrated Services Digital Network format, which is emerging as NATO’s principal switched-transmission resource.

STIP strategic-to-tactical interface STIP strategic-to-tactical interface.

This year’s U.S. European Command-sponsored Combined Endeavor 2000 exercise provided a venue for comprehensive trials of STIP in supporting communications with many other nations’ tactical and strategic systems.

CE 2000

CE 2000 was held during May (see related story) with more than 35 NATO and Partnership for Peace nations and organizations participating. The exercise, now in its sixth year, has measured and documented the interoperability existing between an increasing number of national tactical systems. Also, CE has served to stimulate development of solutions to create mutual interoperability and has influenced new-system acquisition decisions to that end.

CE has achieved near-seamless tactical switched, router-based and transmission multinational networks. The exercise now hosts a sophisticated and unique multinational testbed, appropriate for interoperability testing of the U.S. STIP gateway with many other nations’ switches.

Need for STIP

NATO and PfP nations have started to aggressively upgrade or replace their military analog networks with modern digital systems that apply many commercial techniques. The NATO core network/NATO general-purpose communications segment is the lead model for this trend. Taking advantage of European commercial telecommunications offerings, these new NATO strategic/public networks will be based upon a common Euro-ISDN interface to connect to direct subscribers, private-branch exchanges and both strategic and tactical networks. Given this introduction of new Euro-ISDN-based systems into the NATO telecommunications environment, an interface standard and associated gateway product were required to assist interoperation of the new ISDN networks with existing tactical switched networks of allied and PfP nations.

The DSTG STANAG has been developed over the last few years to meet the operational requirements NATO’s Command, Control and Communications Agency has specified. The Netherlands government’s TNO-FEL labs designed and produced the initial gateway product (STIP) under NC3A’s guidance.

STIP was initially used in the laboratory environment to help test, evaluate and validate the specifications and performance for developing the DSTG standard. However, given the rapid movement toward ISDN networks in Europe, the availability of a DSTG capability has quickly become critical to emerging military-communications upgrade plans across the NATO and PfP communities.

With an eye on this growing interest, STIP’s developers repackaged the mature STIP to produce a deployable product. To fully verify its design and features, developers required a forum in which to demonstrate and verify the STIP gateway capabilities in a much larger and more realistic, operator-oriented environment. The interface standards and STIP required a "live test" of the technical nuances and functional details associated with its operation in the various national strategic and tactical circuit-switched networks to ensure NATO standards were indeed complete and fully incorporated in STIP.

Also, the various national command, control, communications, computers and intelligence user organizations needed to see how STIP could interface with their existing tactical systems in a real-world environment, and understand or consider the best implementation in future communications systems and networks.

For instance, STIP’s modular design allows the use of different types of tactical interface boards. The initial STIP version incorporated a European-communications type of interface. The U.S. version required a redesign of this board.

STIP provides all the necessary interworking functions to automatically handle both data and voice services. In its maximum configuration, STIP can support up to 16 user circuits. Secure voice and data connections over STIP can also be achieved, and the user determines which options and interfaces will be used.

Also, the U.S. C4I acquisition community is determining the near-term and long-range implementation plans for this new capability. For instance, the gateway functions could be implemented in a stand-alone box configuration or embedded into existing or emerging system designs.

Testing STIP

CE provided the ideal venue for the development community, acquisition community and user community to come together to verify multinational interoperation and to refine and resolve issues associated with this new interoperability requirement.

At EUCOM’s request, the U.S. Army’s Commander-in-Chief Interoperability Program Office at Communications-Electronics Command responded to an immediate operational need for a tactical-to-commercial ISDN interface during the Kosovo operation. CIPO pulled together the development community’s technical expertise and helped facilitate the user community’s (EUCOM, 5th Signal Command and 7th Signal Brigade) requirements statement.

User requirements from EUCOM were collected and then reviewed with the NC3A/TNO-FEL design and the available previous STIP test data. Based on this information, the U.S. acquisition community (CECOM, CIPO and the program manager for Warfighter Information Network-Tactical) ensured these emerging standards could be achieved in a future PM WIN-T operational-requirements document as a "born joint/coalition capable" system.

In addition, to ensure the present MSE/TRITAC systems will function correctly with these emerging NATO interfaces, the acquisition team quickly proceeded with developing a stand-alone U.S. STIP variant. In less than nine months, the development and acquisition communities moved from a paper design to a multinational-user test event at CE 2000.

CE results

During CE 2000, the U.S.-modified STIP was successfully tested with 7th Signal Brigade switches. Testing was conducted with 14 other nations’ tactical-communications systems. The tests focused on voice calls across various national ISDN and tactical networks with a channel rate up to 64 kilobits per second. The tests were held over both wire and wireless transmission media.

Given these results, U.S. operational users and the U.S. acquisition community are confident the strategic-to-tactical gateway requirements have been well-defined and proven. As envisioned by NATO and EUCOM, the U.S. STIP gateway can deliver a flexible and interoperable interface for current and future multinational networks, which may be a critical part of future NATO and PfP deployments.

The way ahead

Because the ISDN interface specified for the DSTG is, in principle, able to support all the services required for international tactical-to-tactical connections, NATO nations are now specifying the necessary extensions to the DSTG standard for this. For the future, this would mean that only one type of gateway would be required to support both strategic-tactical as well as tactical-to-tactical connection scenarios.

Most of these extensions to the current DSTG standard have already been implemented in STIP. EUCOM is now providing the U.S. warfighter with an initial STIP capability and is exploring the option of fielding/acquiring more STIPs for future exercises and operations.

Mr. Carpenter works at EUCOM’s J6-X office, as does Mr. Jannis, a Mitre employee. Mr. Sardi is assigned to CIPO. Mr. van Engelshoven works at NC3A.

Acronym QuickScan
C4I – command, control, communications, computers and intelligence
CE – Combined Endeavor
CIPO – Commander-in-Chief Interoperability Program Office
DSTG – digital strategic-tactical gateway
EUCOM – (U.S.) European Command
ISDN – Integrated Services Digital Network
MSE – mobile-subscriber equipment
NATO – North Atlantic Treaty Organization
NC3A – N(orth Atlantic Treaty Organization) Command, Control and Communications Agency
PfP – Partnership for Peace
PM WIN-T – program manager for Warfighter Information Network-Tactical
STANAG – (NATO) standards agreement
STIP – strategic-tactical interface prototype
TRITAC – triservices tactical

dividing rule

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