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The research task group NATO STO/IST-150 «NATO Core Services profiling for Hybrid Tactical Networks» is working towards profiling Core Services for the tactical domain, which can be characterized as DIL (disconnected, intermittent and limited) environments. In this context, our work is intended to feed into future spirals of the Federated Mission Networking (FMN) concept, which, until recently, has been mostly focused on fixed/stable infrastructure networks. In IST-150, we specifically address information exchange needs of deployed coalition forces. Hence, our work is an enabler for the future of command and control systems, which will need to use efficient and appropriate solutions ensuring timely delivery of data and information superiority up to the last mile. In IST-150 we have analyzed and experimented with several message broker mechanisms for information exchange, including the NATO recommended WS-Notification standard for publish/subscribe. We have found that the Message Queuing Telemetry Transport (MQTT) industry standard exhibits low overhead and is worth further studies. In this paper, we continue our analysis in the application of MQTT to tactical networks. We pursue a comparative experiment between three different approaches to sharing data in a federated environment. The first and the second approaches involve multiple MQTT brokers, using the MQTT bridge and a bespoke MQTT mesh approach respectively. The third approach is a brokerless solution based on UDP. The paper investigates these approaches from a performance viewpoint, varying characteristics such as data exchange frequency, network delay and packet loss in an emulated tactical network. The data exchange consists of Blue Force Tracking information transmitted by all units. We present the obtained performance results between brokers considering the different network characteristics. Importantly, we identify the brokers’ advantages and bottlenecks allowing a better understanding of the conditions in which they can be deployed.

This paper describes a hierarchical queuing mechanism designed to monitor and control radio buffers while delivering web services in tactical networks. Our solution was motivated by the restrictions imposed by VHF radios, which have large coverage (∼20 km) but very low data rate (e.g. up to 9.6 kbps). Therefore we implemented two queues, one for messages (Qm) and another for IP packets (Qp), shaping the user-generated data traffic to avoid buffer overflow. The queues complement each other, behaving like control points in a feedback loop. Both control points use the current radio buffer occupancy to decide when to dequeue messages and IP packets. We studied the performance of a prototype in a testbed using real military radios with focus on two variations of our control mechanism (reactive/proactive). The quantitative analysis shows our queuing mechanism successfully avoiding buffer overflow under challenging network conditions.

This paper sketches a service-oriented and hierarchical queuing mechanism designed to manage radio buffers while delivering web services. The goal is avoid buffer overflow implementing a three-level queuing mechanism. The first level is the message queue which stores messages from user-facing services. At the second level, the messages are fragmented into IP packets which are stored in the packet queue. Finally, the third level is the radio buffer itself. As a result, a multi-homed node has queues for each radio, capturing the likely differences of data rate, buffer size and current usage. A prototype based on web services was tested using real military radios; VHF radios with large coverage (∼20 km) but very low data rate (2.4–9.6 kbps). We analyzed the trade-offs within the system configuration, targeting at an optimal and robust radio buffer management.

In this paper, we describe the need, requirements and challenges for implementing a global information grid. The grid connects all participating elements in a military mission and provides them with all mission-relevant information in a timely and secure manner, independent of the used command and control information systems (C2IS), the available communication technologies, the degree of mobility, and the kind of communication networks. Furthermore, we provide an outline for a solution for a Shared Information Space, an implementation of a global information grid meeting these requirements. The proposed Shared Information Space is a concept for a distributed database with an efficient, secure and flexible replication mechanism that features a context-based filtering mechanism (depending on the role, mission, and device) and takes the bandwidth restrictions and disruptions of tactical networks into account. Furthermore, the Shared Information Space acts as a generic mediation service, converting between different interoperability standards. C2IS can connect to the Shared Information Space via a new lightweight Access API1 or via established military standards like NFFI2, NVG3 and MIP4.

In this paper, we describe our experiment and demonstration in applying Service Oriented Architecture (SOA) to mobile nodes in the tactical domain. Our scenario encompasses two convoys that exchange information using NATO standards in order to achieve Friendly Force Tracking between different nations. NATO has identified the WS-Notification standard for the publish/subscribe pattern, so we use that as our messaging middleware to convey NATO Friendly Force Information (NFFI) data. We use a hybrid setup consisting of real nodes using Wireless Broadband Mobile Networks (WBMN) for one convoy and emulated nodes using the Common Open Research Emulator (CORE). The experiments involved components provided by nations participating in the NATO research task group (RTG) IST-RTG-118 “SOA recommendations for disadvantaged grids in the tactical domain”. The group addresses the challenge of implementing the SOA paradigm at the tactical level by providing guidance and best practices. In our work we provide empirical results from our work on publish/subscribe, and give recommendations as to the applicability of the standard in the tactical domain.

The NATO research task group IST-118 titled “SOA recommendations for disadvantaged grids in the tactical domain” is addressing the challenge of implementing the Service Oriented Architecture (SOA) paradigm at the tactical level by providing guidance and best practices in the form of a Tactical SOA Profile. The group will conduct identification and feasibility assessments of possible improvements of the Tactical SOA Profile, over a series of live and emulated experiments. In this paper, we describe our first experiments in applying SOA Web services to mobile nodes that are connected using Wireless Broadband Mobile Networks (WBMN) in the tactical domain. The experiments involved components provided by various nations, including radio hardware equipment, the Publish/Subscribe messaging service and NATO Friendly Force Information (NFFI) (as our functional service). We measured the system performance at service and physical (radio) levels in the presence of network disruption. We conclude by presenting the results of the experiments and a view of future work.

In this paper, we introduce an architectural concept for the adaption of SOA-technology (in particular Web services) in order to enable operational use in the tactical domain (typically featuring low-bandwidth communication links with high delays and frequent disruptions). For this purpose, an Enterprise Service Bus specially tailored for the tactical domain (a “tactical ESB”) is used as a technical infrastructure for the SOA. On the network side, a “tactical router” provides connections to different radio technologies (e.g. VHF, HF based radios, satellite communication, etc.). A specially tailored cross-layer middleware is introduced to coordinate ESB (infrastructure) services with the tactical router. The middleware uses a specific state exchange mechanism in order to increase the efficiency of the overall system. Therefore, it obtains characteristics of the network environment and takes advantage of them in order to improve the quality of data transfers. In addition, a prototypical implementation of the architectural concept is briefly described. There, the designed components and interfaces were prototypically implemented and coupled with RuDi (an Apache CXF - based ESB by IABG [4]) and an in-house developed prototype of a tactical router.

We present a tool box for functional testing of complex distributed IT systems specially tailored for the tactical environment. In order to construct suitable test beds for such systems we capture their 'ambient' infrastructure by means of virtualization and real-time simulation. As an example, we describe how our approach can be used for testing a complex distributed system consisting of (multiple instances of) a tactical command and control information system, a communications server system and a radio communications system. The combined system is part of the standard equipment of various German Army mobile platforms. Aside testing, our tool box also has many potential applications in the domain of training support.