Ketil Lund

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.

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.

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.

Distributed chat in dynamic networks

Chat is becoming increasingly important in military operations. XMPP is the de facto chat protocol in use in NATO today. XMPP is intended for use in stable networks with high bit rate (e.g., LAN, Internet) and does not function well in military tactical networks where resources are scarce and disruptions are frequent. In this paper, we present our novel decentralized solution specially tailored for multi user chat in tactical mobile ad-hoc networks. Our protocol is implemented in Java, and then tested in emulated network conditions. Compatibility with XMPP is achieved through the use of a gateway, so that compatibility with existing deployed chat infrastructure is ensured. Our tests show that our chat solution has a higher message delivery rate in poor conditions than XMPP.

A protocol for robust and efficient service discovery in large, highly mobile radio networks

Existing service discovery mechanisms for ad hoc networks are often designed with one specific network type in mind. Solutions capable of handling highly mobile nodes usually have high bandwidth requirements, particularly as the number of nodes increases. The bandwidth requirement can be reduced by locally caching state information, but this increases the risk of nodes having outdated state information when mobility is high. Some solutions avoid these two issues by tightly coupling service discovery with the routing mechanism itself. However, this requires that nodes are homogeneous on the network layer. We propose a solution that leverages the special properties inherent in broadcast-based radio networks. In such networks, every node within transmission range will hear a transmission, be it unicast or broadcast. Each node therefore aggregates relevant service information and broadcasts it at regular intervals. Unnecessary transmissions are suppressed by efficiently synchronizing local state information. In this paper, we describe the Mist-protocol, a robust and efficient adaptive service discovery protocol, that supports large, highly mobile networks consisting of heterogeneous nodes. We test the protocol in large scale simulations in both static and mobile environments. Finally, we show that it is feasible to actually implement the design by providing a proof-of-concept prototype, which has been evaluated in a small scale experiment.

Toward federated mission networking in the tactical domain

NATO is currently working on the Federated Mission Networking (FMN) concept, which will become the foundation for establishing mission networks in the future. The realization of the FMN concept is described in the NATO FMN Implementation Plan (NFIP). The information infrastructure outlined in NFIP today builds on the concept of service-oriented architecture in order to achieve interoperability, and bases itself on many of the same standards and specifications as the ones identified through NATO Network Enabled Capabilities (NNEC). The NNEC SOA Baseline [1] identifies a number of core enterprise services that represent the common functionality needed to build an interoperable service-oriented infrastructure in a federation. It further identifies which standards should be used to realize these core services while ensuring interoperability between the federation members. A subset of these capabilities includes messaging services, collaboration services, service discovery, and security services. This article looks into each of these foundational core services, presents the challenges related to extending support for these services into the tactical domain, and identifies potential solutions.

Bandwidth optimizations for standards-based publish/subscribe in disadvantaged grids

NATO has identified Web services as a key enabler for its network enabled capability. Web services facilitate interoperability, easy integration and use of commercial off-the-shelf components, and while request/response-based schemes have hitherto been predominant, publish/subscribe-based services are gaining ground. SOAP-based Web services, however, introduce considerable communication overhead, and optimization must be done to enable use on the tactical level. Data compression is one such optimization, and it works well for large messages. We claim that the inherent characteristics of publish/subscribe-based Web services are such that using difference-based compression will allow effective compression also for small messages. In this paper we present the design and implementation of a proof-of-concept mechanism called ZDiff, which we have tested on several types of military data formats. Together with our SOAP-based proxy system it can be used together with commercial off-the-shelf Web services software. The results show that difference-based compression outperforms traditional compression for small messages, at the same time as it never performs worse than traditional compression for larger messages.

Coalition Networks for Secure Information Sharing (CoNSIS) (Invited Paper)

The multilateral CONSIS project is related to the migration towards Network Enabled Capabilities (NEC) in the participating countries. As such, CoNSIS aligns with the overarching objective of the NATO NEC (NNEC) to enhance the Alliances ability to federate various capabilities at all levels, military (strategic to tactical) and civilian through networking and information infrastructure. Providing security and efficient network management have been important aspects of this work. The work has been a combination of theoretical studies and field experiments in order to get hands-on experience with the involved technologies. This possibility of addressing radios, networks, SOA, security and management together, has given us knowledge on how the different technologies affect each other and how they may be combined. A follow up project (CoNSIS phase II) is being planned with startup in 2014.