Frank T. Johnsen

Using web services to realize service oriented architecture in military communication networks

The principles of network enabled capability highlight the need for seamless information exchange. The service oriented architectural paradigm has been recognized as one of the key enablers to achieve this. At the same time, Web services have become the de facto standard for implementing service oriented architecture. However, these technologies have been developed for environments with abundant data rates, environments which are very different from military tactical networks. In this article, we present possible solutions and remaining challenges on the way toward also realizing service oriented architecture on the tactical level. Our goal is to make it possible to take advantage of the benefits promised by this architectural paradigm at all military levels, ranging from strategic to tactical networks.

Robust web services in heterogeneous military networks

NATO Network Enabled Capability is first and foremost about achieving better interaction between the different actors involved in military operations. This implies more efficient exchange of information. Consequently, the NATO information infrastructure will consist of a federation of systems, including a plethora of different information and communication systems, as well as a mix of new and legacy systems. NATO recommends a service-oriented architecture approach based on Web services to enable such a federation. In this article we explain how the communication protocols normally used in Web services are unsuited for disadvantaged and heterogeneous networks. We then present our prototype proxy, which enables the use of standard unmodified Web services across all network types, including tactical networks with low data rates and frequent disruptions. It is designed to work with existing security mechanisms, and also offers further optimizations in the form of optional plug-ins.

Web services discovery across heterogeneous military networks

NATO has identified Web services standards as a key enabler for interoperability between the different military systems used by various NATO nations. Compared to many civilian systems, military networks vary greatly in terms of computing resources, network bandwidth, mobility and stability, and distributed applications use several different networks concurrently or interact across them. In such dynamic and heterogeneous environments, runtime service discovery is a necessity. According to the W3C, discovery is the act of locating a machine-processable description of a Web service-related resource that may have been previously unknown and that meets certain functional criteria. In this article we present our approach to service discovery, where we combine Web services standards and proprietary solutions using our prototype interoperability gateway. This approach has been experimentally evaluated in a military experiment featuring both mobile ad hoc networks and fixed infrastructure networks, and the results show that transparent discovery between proprietary solutions and Web services discovery standards can be achieved.

Workload Characterization for News-on-Demand Streaming Services

This paper focuses on design issues for multimedia distribution architectures and the impact workload characteristics have on architecture design. Our contribution is an analysis of server load and user behavior in a news-on-demand environment, with focus on access patterns, popularity modeling, and the formation of traffic peaks. Finally, we evaluate an existing synthetic workload generator, MediSyn, and suggest some enhancements which will improve its suitability for news-on-demand workload modeling.

Mist: A Reliable and Delay-Tolerant Publish/Subscribe Solution for Dynamic Networks

In this paper, we present Mist: a reliable and delay-tolerant middleware for information dissemination between highly mobile devices. Mist provides publish/subscribe with guaranteed message delivery in fully connected networks. Through emulation we show how the middleware is effective in static networks, as well as in dynamic topologies with high mobility. We describe how Mist is able to scale using a topic routing mechanism, allowing groups of mobile units to cooperate with infrastructure-based P2P-networks. Finally, we describe recent experiments where Mist has been employed successfully in real-life deployments. The implementation of the middleware, written in Java, is released as open source.

Efficient Web Services in Mobile Networks

Efficient solutions for Web services on mobile devices would allow truly global, platform independent, and interoperable information access, anywhere and at any time. While Web services are continuously gaining ground, they are commonly reserved for use on personal computers and high-capacity servers. However, mobile devices are gradually becoming more advanced in terms of processing resources and wireless communication capabilities, making it feasible to use Web services on such devices as well. Some of the challenges related to mobile Web services are limited bandwidth, high communication latency and high communication cost. In this paper, we focus on techniques for reducing XML overhead as a solution to overcome these challenges. Compression is a well known technique for reducing bandwidth consumption. Our contribution is an evaluation of compression techniques for use with Web services in mobile networks. In addition to performing simulations, we have verified our results using real GPRS and UMTS network connections.

Delay and disruption tolerant Web services for heterogeneous networks

Web services technology is considered a key enabler for NEC. However, existing Web service protocols are designed for use over the Internet, and cannot necessarily be directly applied in military tactical networks where bandwidths are low and communication disruptions are frequent. In this paper we present a novel prototype proxy solution which adds both delay and disruption tolerance to SOAP. The ¿Delay and disruption tolerant SOAP Proxy¿ solution can bridge heterogeneous networks and offers store-and-forward capabilities, delay tolerant network capabilities and swappable transport protocols while retaining backward compatibility with COTS Web service clients and servers. The proxy solution does not rely upon parsing or inspecting the SOAP messages, which allows for end-to-end security through encryption.

Information-centric networking in the tactical domain

Information-centric networking is a communication paradigm where there is no focus on endpoint addressing; rather, it is an attempt to achieve efficient information dissemination by focusing on the content that is distributed. In this article we describe how information-centric networking can be leveraged in order to extend NATO core enterprise services (CES) into the tactical domain. The paradigm can be implemented using decentralized publish/subscribe along with content caching. We present our information-centric middleware, Mist, and perform a comparative evaluation with an existing framework called Haggle. Mist is tailored to mitigate challenges encountered in mobile ad hoc networks. As a proof of concept, we implement a gateway between Mist and WS-Notification, which is the standard used in the Publish/Subscribe CES. This shows that with little effort it is possible to create gateways from networks using Mist to Web services-enabled infrastructure networks, ensuring compatibility and interoperability with higher levels in the chain of command, and also with other nations.

Enabling Publish/Subscribe with COTS Web Services across Heterogeneous Networks

In scenarios such as search-and-rescue operations, it may be required to transmit information across multiple, heterogeneous networks, often experiencing unreliable connections and limited bandwidths. Under such conditions, Publish/subscribe-based communication, combined with store-and-forward capabilities in the network nodes, greatly improves the ability to transmit information. At the same time, it is desirable to use commercial, standards-based software as much as possible, in order to reduce both cost and development time, and to ease the interconnection of systems from different organizations. In this paper, we present our prototype middleware solution called the Delay and Disruption Tolerant SOAP Proxy (DSProxy) which adds Publish/Subscribe functionality to standard, unmodified Web services. Together with its ability to make Web services delay and disruption tolerant, the DSProxy enables SOA based on Web services in scenarios as described above. The DSProxy has been tested in field trials, with promising results.

An Emulated Test Framework for Service Discovery and MANET Research Based on ns-3

In this paper we present our framework for emulated evaluation of service discovery protocols in mobile ad-hoc networks (MANETs). Emulation is preferable to simulation when evaluating real world software implementations, as it provides a controlled network environment without requiring modifications to the software. We base our work on the open-source simulator ns-3, which also has support for network emulation. Our own test framework consists of a set of scripts running in Linux Containers, providing a means to bootstrap and populate service discovery protocols with services and queries. Our setup allows us to perform controlled and repeatable service discovery protocol experiments in MANETs with a high degree of automation. Experiment series are set up, controlled, and statistics calculated by scripts, thus enabling complex, large, and real-time evaluations to be performed without human interaction.