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In military mission contexts with limited network connectivity, availability and utilization of information may be improved through adaptive information processing over a federated cloud infrastructure. Orchestration mechanisms to dynamically distribute data and computing tasks over the available partner cloud infrastructures enable improved exploitation of the information processing, storage, and communication means that are ever more available and powerful in battlefield situations.

Service fabric management in Fog Computing is a challenging task, which has to deal with a complex and resource scarce environment. We argue that approaches leveraging Value-of-Information (VoI) concepts and tools are particularly interesting to support the realization of that objective. This paper describes innovative methodologies and reference models for the service fabric management for Fog Computing applications. First, we formalize the VoI concept and discuss its adoption in Fog Computing environments. Then, we propose a formal model that aims at maximizing the allocation of Fog services from a value-based perspective. To overcome the complexity of this model, we present two possible approaches (simulation-based optimization and a model approximation) and we compare them by adopting Evolutionary Algorithms (EAs) as optimization techniques. Experimental results prove the validity of both models in finding resource allocation solutions capable of minimizing network latency and maximizing the utility for the end-users of Fog Computing services. Finally, we show how the results of the approximated model can be adopted as a first approximated approach for resource management of Fog Computing services.

Smart City services leverage sophisticated IT architectures whose assets are deployed in dynamic and heterogeneous computing and communication scenarios. Those services are particularly interesting for Humanitarian Assistance and Disaster Relief (HADR) operations in urban environments, which could improve Situation Awareness by exploiting the Smart City IT infrastructure. To this end, an enabling requirement is the discovery of the available Internet-of-Things (IoT) resources, including sensors, actuators, services, and computing resources, based on a variety of criteria, such as geographical location, proximity, type of device, type of capability, coverage, resource availability, and communication topology / quality of network links. To date, no single standard has emerged that has been widely adopted to solve the discovery challenge. Instead, a variety of different standards have been proposed and cities have either adopted one that is convenient or reinvented a new standard just for themselves. Therefore, enabling discovery across different standards and administrative domains is a fundamental requirement to enable HADR operations in Smart Cities. To address these challenges, we developed MARGOT (Multi-domain Asynchronous Gateway Of Things), a comprehensive solution for resource discovery in Smart City environments that implements a distributed and federated architecture and supports a wide range of discovery protocols.

Fog Computing is a new computation paradigm, recently emerged from the convergence of IoT, WSN, mobile computing, edge computing, and Cloud Computing, which is particularly well suited for Smart City environments. Fog Computing aims at supporting the development of time-sensitive, location-, social-, and context-aware applications by using computational resources in close proximity of information producers and consumers, such as increasingly common cheap and powerful modern hardware platforms. However, realizing Fog Computing solutions for Smart Cities represents a very challenging task, because of the massive amount of data to process, the strict resource and time constraints, and the significant dynamicity and heterogeneity of computation and network resources. These formidable challenges suggest taking into consideration new information and service model solutions that explore several trade-offs between processing speed and accuracy. Along these guidelines, we designed the SPF Fog-as-a-Service platform, which proposes a new information-centric and utility-based service model and allows the definition of self-adaptive and composition-friendly services, which can execute either on edge devices or in the Cloud. In numerous evaluations, SPF proved to be a very effective platform for running Fog services on heterogeneous devices with significantly different computational capabilities while also demonstrating remarkable ease of development and management characteristics.

Natural disasters occur unpredictably and can range in severity from something locally manageable to large scale events that require external intervention. In particular, when large scale disasters occur, they can cause widespread damage and overwhelm the ability of local governments and authorities to respond. In such situations, Civil-Military Cooperation (CIMIC) is essential for a rapid and robust Humanitarian Assistance and Disaster Relief (HADR) operation. These type of operations bring to bear the Command and Control (C2) and Logistics capabilities of the military to rapidly deploy assets to help with the disaster relief activities. Smart Cities and Smart Environments, embedded with IoT, introduce multiple sensing modalities that typically provide wide coverage over the deployed area. Given that the military does not own or control these assets, they are sometimes referred to as gray assets, which are not as trustworthy as blue assets, owned by the military. However, leveraging these gray assets can significantly improve the ability for the military to quickly obtain Situational Awareness (SA) about the disaster and optimize the planning of rescue operations and allocation of resources to achieve the best possible effects. Fusing the information from the civilian IoT sensors with the custom military sensors could help validate and improve trust in the information from the gray assets. The focus of this paper is to further examine this challenge of achieving Civil-Military cooperation for HADR operations by leveraging and fusing information from gray and blue assets.

Tactical edge networks represent a uniquely challenging environment from the communications perspective, due to their limited bandwidth and high node mobility. Several middleware communication solutions have been proposed to address those issues, adopting an evolutionary design approach that requires facing quite a few complications to provide applications with a suited network programming model while building on top of the TCP/IP stack. Information Centric Networking (ICN), instead, represents a revolutionary, clean slate approach that aims at replacing the entire TCP/IP stack with a new communication paradigm, better suited to cope with fluctuating channel conditions and network disruptions. This paper, stemmed from research conducted within NATO IST-161 RTG, investigates the effectiveness of Named Data Networking (NDN), the de facto standard implementation of ICN, in the context of tactical edge networks and its potential for adoption. We evaluated an NDN-based Blue Force Tracking (BFT) dissemination application within the Anglova scenario emulation environment, and found that NDN obtained better-than-expected results in terms of delivery ratio and latency, at the expense of a relatively high bandwidth consumption.

The Anglova scenario was developed as part of the NATO IST-124 Research Task Group on Improving Connectivity and Network Efficiency in Heterogeneous Tactical Networks. Since then, it has been successfully used to conduct emulation-based experimentation by multiple groups. This paper describes extensions to the Anglova scenario for the purpose of experimentation within an Urban environment. In particular, the focus is on Vignette 3 and its extension for the new IST-168 Research Task Group on Adaptive Information Processing and Distribution for Command and Control. © 2019 IEEE.

Data dissemination is one of the fundamental requirements for any military network. Types of data include Situation Awareness data such as position reports, sensor data, and Commander's Operational Orders and Intelligence Reports. Different data types have different dissemination patterns and requirements. Some data types such as position reports are generated by each node and need to be received by every other node. On the other hand, sensor data is generated by a handful of nodes and may be needed by a subset of other nodes. Finally, orders and reports are generated by higher echelon nodes (e.g., a Headquarters node) and need to be disseminated down the command hierarchy. Group communications protocols typically handle dissemination of such data from multiple senders to multiple recipients. In this paper, we evaluate the performance of a number of different group communications protocols for data dissemination. In particular, we evaluate the performance over an emulated tactical edge network using the Anglova scenario. Such an evaluation helps identify the relative strengths and weaknesses of these protocols when they operate in a challenged communications environment with limited capacity, variable latency, and unstable links. © 2019 IEEE.

Mobile military networks are uniquely challenging to build and maintain, because of their wireless nature and the unfriendliness of the environment, resulting in unreliable and capacity limited performance. Currently, most tactical networks implement TCP/IP, which was designed for fairly stable, infrastructure-based environments, and requires sophisticated and often application-specific extensions to address the challenges of the communication scenario. Information Centric Networking (ICN) is a clean slate networking approach that does not depend on stable connections to retrieve information and naturally provides support for node mobility and delay/disruption tolerant communications – as a result it is particularly interesting for tactical applications. However, despite ICN seems to offer some structural benefits for tactical environments over TCP/IP, a number of challenges including naming, security, performance tuning, etc., still need to be addressed for practical adoption. This document, prepared within NATO IST-161 RTG, evaluates the effectiveness of Named Data Networking (NDN), the de facto standard implementation of ICN, in the context of tactical edge networks and its potential for adoption.

In the last decade, governments and municipalities have been investing large amounts of money to improve the style and quality of life of Smart Cities' citizens. This led to a huge adoption of Internet of Things (IoT) installations producing a wide amount of data. To exploit at best the many advantages of the IoT, Smart Cities have also begun to make that data freely accessible through Open Data services. The combination of IoT and Open Data can bring benefits in different fields, including the military domain. More specifically, Humanitarian Assistance and Disaster Relief (HADR) missions would significantly benefit from the integration of military systems with the civilian IT infrastructure of Smart Cities. In this context, the deluge of data generated by the IoT calls for dedicated solutions to analyze it and disseminate the results. This paper presents an evaluation of the capabilities of SPF, the Fog-as-a-Service platform we designed for tactical environments, in supporting a hypothetical but realistic HADR mission in the Helsinki Smart City. The paper demonstrates how the possibilities brought by the integration of SPF with the Open Data services offered by the city of Helsinki can significantly help the work of the emergency team, in particular with regards to the quick detection of clear and congested roads for relief organization and coordination.

The Anglova scenario is designed to support experimentation with tactical networking environments and provides node mobility and network connectivity for a realistic battalion-sized military operation consisting of three vignettes, including the deployment of armored vehicles, surveillance of the maritime domain and an urban operation with a naval component. Altogether, the scenario includes 283 nodes and lasts over four hours with detailed mobility and pathloss data for each node. Also included with the scenario are radio models for the different radios that would be part of a heterogeneous network. The scenario has been developed by the NATO IST-124 Research Task Group and released into the public domain in order to facilitate experimentation with networking protocols and algorithms by the community at large. While primarily designed for the Extendable Mobile Ad-hoc Network Emulator (EMANE), the scenario can also be adapted to other experimentation environments.

Tactical Networks (TNs) are challenging communication environments at the base of modern network-centric warfare, characterized by limited resources, frequent link disruption, and partitioning. TNs typically involve a multitude of units belonging to different domains that need to share information securely over shared and constrained links to enable cooperation. Federation Services offer a model for policy-based information sharing between multiple domains, which permit individual forces and organizations to match mission requirements by allowing a fine-grained selection of the data to exchange. However, while the Federation model alone is not enough to ensure confidentiality and integrity of data transmissions over shared network resources, traditional end-to-end cryptography solutions might not suit low-resources, bandwidth-constrained networking environments. This paper discusses two solutions to enable secure and efficient information sharing in multidomain TNs using Federation Services. The first solution enables the definition of multiple groups of authenticated federates and provides information access control to information senders by leveraging on Attribute-Based Encryption techniques to encrypt federated messages and define, on a per-message basis, a subset of groups that can access the data. The second solution enhances the first one by addressing link disruption and network partitioning in TNs by introducing a distributed group key management service (GkMS) architecture.

Recent advances in Smart City infrastructures and the Internet of Things represent a significant opportunity to improve people’s quality of life. Corresponding research often focuses on Cloud-centric network architectures where sensor devices transfer collected data to the Cloud for processing. However, the formidable traffic generated by countless IoT devices and the need for low-latency services raise the need to move away from centralized architectures and bring the computation closer to the data sources. To this end, this paper discusses SPF, a middleware solution that supports IoT application development, deployment, and management. SPF runs IoT services on capable devices located at the network edge and proposes an information-centric programming model that takes advantage of decentralized computation resources located in the proximity of application users and data sources. SPF also adopts Value-of-Information based methods to prioritize the transmission of essential information.

Emulation environments are an effective approach to experimenting with and evaluating network protocols, algorithms, and components. This paper describes a joint effort by the NATO Science & Technology Organization's IST-124 Research Task Group to evaluate the scalability of OLSRv1 and OLSRv2 in an emulation environment within a military scenario. The scenario includes detailed mobility patterns for a battalion-sized operation, which has been developed by military experts in planning and executing live exercises. The mobility patterns are used to drive the network emulation. The scalability of OLSRv1 and OLSRv2 (with and without MPR) is assessed by emulating different network sizes and estimating the overhead. Moreover, the unicast packet delivery ratio is calculated for the different OLSR configurations. The results show that with the chosen OLSR update rates, only OLSRv2 with MPR mechanism scales up to 96 nodes.

Emulation environments are an effective approach to experimenting with and evaluating network protocols, algorithms, and components. This paper describes a joint effort by the NATO Science & Technology Organization's IST-124 task group to develop and distribute an emulation environment and scenario. The most significant contribution is a vetted and militarily-realistic scenario that provides a rich combination of elements for experimentation. The scenario includes detailed mobility patterns for a battalion-sized operation over the course of two hours, which has been developed by military experts in planning and performing real exercises. The mobility patterns are used to drive the network emulation.

Managing the extremely large volume of information generated by Internet-of-Things (IoT) devices, estimated to be in excess of 400 ZB per year by 2018, is going to be an increasingly relevant issue. Most of the approaches to IoT information management proposed so far, based on the collection of IoT-generated raw data for storage and processing in the Cloud, place a significant burden on both communications and computational resources, and introduce significant latency. IoT applications would instead benefit from new paradigms to enable definition and deployment of dynamic IoT services and facilitate their use of computational resources at the edge of the network for data analysis purposes, and from smart dissemination solutions to deliver the processed information to consumers. This paper presents SPF (as in “Sieve, Process, and Forward”), an SDN solution which extends the reference ONF architecture replacing the Data Plane with an Information Processing and Dissemination Plane. By leveraging programmable information processors deployed at the Internet/IoT edge and disruption tolerant information dissemination solutions, SPF allows to define and manage IoT applications and services and represents a promising architecture for future urban computing applications.

Tactical Edge Networks provide one of the most challenging communication environments. In order to cope with node mobility, constrained resources, and link unreliability, communication solutions designed for Tactical Edge Networks typically present highly configurable interfaces to be adaptable for various networking conditions. However, the extreme dynamicity and heterogeneity of tactical scenarios call for network-aware, adaptive communication systems that continuously re-tune their configuration parameters to match the ever-changing network conditions. This paper presents the Dynamic Detect and Adapt Mechanism (DDAM) of the Agile Communication Middleware, a distributed solution to perform network monitoring and communication adaptation specifically designed for Tactical Edge Networks. The present work focuses on two components of the DDAM: NetSensor, which provides efficient monitoring of the network status, and NetSupervisor, which is responsible for characterizing the network technology used to connect a pair of nodes in the network. The presented results show that our solution can accurately identify the technology used to establish links between nodes.

One of the chief computer security problems is not the long list of viruses and other potential vulnerabilities, but the vast number of systems that continue to be easy prey, as their system administrators or owners simply are not able to keep up with all of the available patches, updates, or needed configuration changes in order to protect them from those known vulnerabilities. Even up-to-date systems could become vulnerable to attacks, due to inappropriate configuration or combined used of applications and services. Our mobile agent-based security tool (MAST) is designed to bridge this gap, and provide automated methods to make sure that all of the systems in a specific domain or network are secured and up-to-date with all patches and updates. The tool is also designed to check systems for misconfigurations that make them vulnerable. Additionally, this user interface is presented in a domain knowledge model known as a Concept Map that provides a continuous learning experience for the system administrator.

Service-oriented architectures (SoAs) are a popular paradigm for enterprise and data center computing but normally do not perform well on tactical networks, which are often degraded in terms of bandwidth, reliability, latency, and connectivity. This paper presents the agile computing middleware and in particular a transparent network proxy and associated protocols that help address the impedance mismatch that occurs between SoAs and tactical and DIL (Disconnected, Intermittent, and Limited) networks.

Many important public services, such as security and public health, as well as the modern tactical military scenarios, rely on Service-oriented Architectures (SoAs) and commercial off-the-shelf (COTS) components to enable the quick development and deployment of distributed services to respond quickly, reduce costs, and ease system integration. However, SoAs make use of verbose networking technologies and require reliable and relatively high bandwidth communications. Tactical scenarios normally cannot rely on such infrastructure and events like natural disasters can severely damage the network infrastructure in rural and urban environments. Thus, there is a need to develop solutions that provide SoA-based application and services running on heterogeneous and often constrained devices that compose tactical and mobile ad-hoc networks with Quality of Service (QoS) levels that meet their requirements. This paper presents the QoS-enabling features and the gateway operational mode (GM) of ACM NetProxy, the network proxy component of a communications middleware specifically developed to support applications in challenged networks. GM allows nodes in an ad-hoc wireless network to be quickly organized and to shape outbound communications to reduce bandwidth consumption and provide QoS. Experimental results obtained during a test in a field demonstration event show its efficiency.

The ever increasing number of mobile devices in Smart Cities and their heavy use, not only for personal communication but also as a distributed network of sensors, generate a data deluge that stresses the traditional wireless communication infrastructure. The opportunistic networking paradigm seems particularly well suited to the Smart City scenario because it exploits resources that temporarily fall into the connection range of mobile devices as communication proxies, thereby providing cheaper and more energy efficient alternatives to the use of the cellular city network and actively contributing to its offloading. However, its efficacy highly depends on the effectiveness of discovering and using those resources. To improve the effectiveness of opportunistic networking in Smart Cities, we propose a solution which exploits a prediction model tailored for the urban environment that, by detecting complex recurring patterns in nodes' contacts, can forecast the future availability of strategic communication resources. Experimental results obtained in a simulated environment show that our solution can improve the dissemination process and ease the access to the wired network infrastructure.

The increasing adoption of COTS hardware and software technologies in tactical scenarios raises the issue of supporting the deployment of legacy and COTS applications in extremely dynamic and challenging environments such as tactical edge networks (TENs). COTS applications adopt standards devised for wired Internet environments or corporate networks, such as service oriented architectures, and TCP and UDP, thus exhibiting severe reliability and performance problems on TENs. To support the reuse and deployment of COTS applications in TENs, there is the need to develop solutions that mediate the application requirements with the communication semantics of TENs. This article presents an overview of the challenges in deploying COTS applications in TENs and presents NetProxy, a state-of-the-art solution explicitly designed to address them.

Service Oriented Architectures allow for seamless integration of heterogeneous systems and extensive service reuse; characteristics that led to a wide adoption of this paradigm in the enterprise and military environment. While SoAs are currently deployed in tactical environments mainly at higher-echelon levels, it is necessary to allow for the exchange of information all the way down to the edge nodes deployed on the ground and back. Because most SoAs implementations were designed to work on reliable infrastructure networks, porting SoAs to the tactical environment requires a complete redesign of the protocol stack to support unreliable, transiently disconnected networks. In this paper, we present our approach to integrate the U.S. Marine Corps's Marine Command and Control Systems and Applications SoA (MC2SA SoA) with DisServicePro, a middleware that supports proactive dissemination and information on demand in tactical edge networks.

Military applications are relying more and more on Commercial Off-The-Shelf (COTS) hardware and software to build their information infrastructure. However, many COTS applications have been designed for wired infrastructure networks, where bandwidth and latency are not a problem, and exhibit severe performance problems when deployed in Tactical Edge Networks. To address the issues that traditional transport protocols, such as TCP, exhibit in this environment, researchers proposed several transport protocol solutions specifically developed for Tactical Edge Networks. However, these solutions require modifications to the applications in order to be adopted. This paper presents the Agile Computing Middleware (ACM) NetProxy: a proxy-based approach to support the deployment of COTS applications on Tactical Edge Networks. NetProxy transparently intercepts the applications' TCP and UDP traffic and conveys it over Mockets-based connections, while also providing other useful features such as stream compression. We tested NetProxy in an emulated environment and the results demonstrate that, besides enabling the deployment of COTS applications, NetProxy is also capable of improving their performance.

Tactical operations often involve the cooperation of multiple actors that need to communicate in a reliable and timely fashion. Numerous critical activities that are performed in this context, such as the dissemination of situational awareness data, or the dissemination of command and control information, present a point-to-multipoint pattern. Therefore, multicast protocols are a suitable approach to perform efficient data dissemination in this context. More specifically, some tactical information requires reliable point-to-multipoint delivery of information. In this paper, we experimentally evaluate four protocols (and corresponding implementations) that have been developed to support reliable multicast communications: NORM, JGroups, OpenPGM, and DisService. We report on two sets of experiments. The first set of experiments measure bandwidth utilization and average delivery time under different emulated network conditions. The second set of experiments performs a more in-depth comparison of the forward error correction approach implemented in NORM with DisService, which adopts an opportunistic approach for information dissemination.

Cellular mobile devices, and in particular smartphones, have become ubiquitous. While bandwidth has steadily increased from 2G devices with Edge to 3G and now 3G LTE (4G), so has the demand for bandwidth intensive applications and streaming of multimedia content. Supporting high densities of such users in urban environments has become a challenge. In this paper, we describe an approach to peer-to-peer cooperative networking that exploits the WiFi interface in peer-to-peer mode in order to reduce the demand on the cellular network while at the same time increasing the reliability of data delivery. We describe multiple scenarios that benefit from such middleware and present some experimental results.

Process integrated mechanisms (PIM) offer a new approach to the problem of coordinating the activity of physically distributed systems or devices. Current approaches to coordination all have well-recognized strengths and weaknesses. We propose a novel architecture to add to the mix, called the Process Integrated Mechanism (PIM), which enjoys the advantages of having a single controlling authority while avoiding the structural difficulties that have traditionally led to its rejection in many complex settings. In many situations, PIMs improve on previous models with regard to coordination, security, ease of software development, robustness and communication overhead. In the PIM architecture, the components are conceived as parts of a single mechanism, even when they are physically separated and operate asynchronously. The PIM models offers promise as an effective infrastructure for handling tasks that require a high degree of time-sensitive coordination between the components, as well as a clean mechanism for coordinating the high-level goals of loosely coupled systems. PIM models enable coordination without the fragility and high communication overhead of centralized control, but also without the uncertainty associated with the system-level behavior of a MAS.The PIM model provides an ease of programming with advantages over both multi-agent sys-tems and centralized architectures. It has the robustness of a multi-agent system without the significant complexity and overhead required for inter-agent communication and negotiation. In contrast to centralized approaches, it does not require managing the large amounts of data that the coordinating process needs to compute a global view. In a PIM, the process moves to the data and may perform computations on the components where the data is locally available, sharing only the information needed for coordination of the other components. While there are many remaining research issues to be addressed, we believe that PIMs offer an important and novel tech-nique for the control of distributed systems.

Tactical edge networks present extremely challenging environments for communications given their wireless ad hoc nature and the inherent node mobility. Military applications such as Blue Force Tracking, inter-team communications, remote unmanned vehicle control, and sensor data mining/fusion thus have to deal with unstable links with limited bandwidth and variable latency. The peculiar characteristics of tactical networks call for peer-to-peer approaches to realize complex, adaptive, and fault-tolerant applications to be deployed in the battlefield. This article reports on our observations from several tactical networking experiments in which we have deployed state-of-the-art applications and services that leverage P2P communications. More specifically, we discuss why P2P approaches are critical for tactical network environments and applications. We then analyze the requirements that should be satisfied by P2P middleware for tactical environments. Finally, we discuss a case study, the Agile Computing Middleware, and present experimental results that demonstrate its effectiveness.

Tactical networks are highly dynamic environments characterized by constrained resources, limited bandwidth, and intermittent connectivity. The limits on communication cause significant delays in the delivery of information to edge users. This paper focuses on an approach to improve the timeliness of access to information via prediction and pre-staging. The approach also incorporates a learning mechanism to dynamically adapt the information prediction algorithm. This capability has been integrated into the DisService peer-to-peer information dissemination system, which opportunistically exploits any available connectivity to address the challenging environment. The extended system, called DisServicePro (for Proactive) predicts the information needs of edge users using their mission description, including the routes that users may take as part of the mission. DisServicePro extends the capabilities of DisService by efficiently and proactively disseminating information to the edge nodes by means of replication and forwarding policies. The proactive behavior is the result of the integration of policies and a distributed learning algorithm that takes into account the history of previously requested information, along with the characteristics of the target nodes and the mission. As new information becomes available, DisServicePro matches it against the mission profile and pushes relevant information to the edge nodes. Information that is selected to be pushed is sorted based on the predicted time to use as well as the confidence value of the prediction.

Information dissemination is extremely difficult in tactical edge networks, which provide one of the most challenging environments for communication. The extremely dynamic nature of the tactical environment makes dissemination algorithms based on overlay networks or epidemic routing ineffective, and calls for ad hoc approaches that can dynamically reconfigure the dissemination process, adapting it to the current network conditions. This paper presents the algorithms for opportunistic information dissemination adopted in the DisService project. In particular, the paper investigates what kind of knowledge can be inferred about the interaction between nodes in a tactical network and how to use that knowledge to improve data dissemination algorithms. The algorithms are tested in a NS3 simulated environment and the results demonstrate the effectiveness of the DisService approach.

Tactical networking environments present significant challenges that must be overcome in order to effectively support net-centric warfare. The wireless and ad hoc nature of these networks implies unreliable connectivity, limited bandwidth, and variable latency. Past and current research has focused on physical and data link layers, routing protocols, transport protocols, and cross-layer aspects. However, significant work is needed at the upper layers to better support application requirements. In our experience, achieving effective communications in tactical environments requires taking into account application requirements and communication patterns, designing a rich interface between the application and communication layers, and realizing a communications middleware specifically adapted to tactical networks. In this article, we report on our observations from several tactical networking experiments and demonstrations and the lessons learned from deployment of the Mockets middleware to support tactical communications. We hope these experiences are useful to others designing and implementing applications and systems for tactical environments.

Realizing adaptive and efficient peer-to-peer service-oriented architectures for MANET environments is a challenging problem. In particular, robust and efficient service discovery and service migration are critical in the constantly changing and bandwidth limited MANET environments. In these scenarios, service migration lays the foundation for self-adaptive architectures. This paper describes the agile computing approach to peer-to-peer service discovery and service migration and provides a performance evaluation of these functions in the context of the agile computing middleware. The experimental results presented in the paper show that applications built on top of the agile computing middleware are capable of opportunistically exploiting transient computing resources in the MANET environment.

Communication between mobile devices in the MANET scenario exhibits significant reliability and performance problems. Traditional communication infrastructures designed for wired networks are not well suited for MANETs because they masquerade network level conditions. In the MANET scenario, instead, there is the need to expose current network conditions to applications, enabling them to adapt their behavior to changes in the quality of the communication links. In the context of a MANET-oriented communication framework (called Mockets), this paper presents a network conditions monitoring component which provides applications with timely and accurate information about communication channel characteristics. In particular, the paper focuses on the measurement of latency, obtained via Round Trip Time measurement, for which it presents three different algorithms. The experimental results show the performance of the different algorithms in a MANET-like emulation environment.