End-to-End Resilience Mechanisms for Network Transport Protocols

The universal reliance on and hence the need for resilience in network communications has been well established. Current transport protocols are designed to provide fixed mechanisms for error remediation (if any), using techniques such as ARQ, and offer little or no adaptability to underlying network conditions, or to different sets of application requirements. The ubiquitous TCP transport protocol makes too many assumptions about underlying layers to provide resilient end-to-end service in all network scenarios, especially those which include significant heterogeneity. Additionally the properties of reliability, performability, availability, dependability, and survivability are not explicitly addressed in the design, so there is no support for resilience. This dissertation presents considerations which must be taken in designing new resilience mechanisms for future transport protocols to meet service requirements in the face of various attacks and challenges. The primary mechanisms addressed include diverse end-to-end paths, and multi-mode operation for changing network conditions

Cloud transactions and caching for improved performance in clouds and DTNs

In distributed transactional systems deployed over some massively decentralized cloud servers, access policies are typically replicated. Interdependencies ad inconsistencies among policies need to be addressed as they can affect performance, throughput and accuracy. Several stringent levels of policy consistency constraints and enforcement approaches to guarantee the trustworthiness of transactions on cloud servers are proposed. We define a look-up table to store policy versions and the concept of Tree-Based Consistency approach to maintain a tree structure of the servers. By integrating look-up table and the consistency tree based approach, we propose an enhanced version of Two-phase validation commit (2PVC) protocol integrated with the Paxos commit protocol with reduced or almost the same performance overhead without affecting accuracy and precision. A new caching scheme has been proposed which takes into consideration Military/Defense applications of Delay-tolerant Networks (DTNs) where data that need to be cached follows a whole different priority levels. In these applications, data popularity can be defined not only based on request frequency, but also based on the importance like who created and ranked point of interests in the data, when and where it was created; higher rank data belonging to some specific location may be more important though frequency of those may not be higher than more popular lower priority data. Thus, our caching scheme is designed by taking different requirements into consideration for DTN networks for defense applications. The performance evaluation shows that our caching scheme reduces the overall access latency, cache miss and usage of cache memory when compared to using caching schemes --Abstract, page iv

Success Factors for SOA Implementation in Network Centric Environment, Journal of Telecommunications and Information Technology, 2011, nr 1

This paper discusses challenges and success factors for service oriented architecture (SOA) implementation in network centric environment. The authors identify 9 fundamental challenges for the SOA approach in order to make the biggest benefit for the NATO NEC (NNEC) and increase the mission effectiveness to the highest extent. They cover the areas of applicability to existing military communications and the ability to reflect military processes. Their range is quite broad, pointing out technological as well as SOA governmental problems. The authors emphasize that any COTS solution available on the market today is able to overcome all of them at once. However, they propose solutions to some of the problems and present quick wins that can speed up the process of achieving capabilities in a heterogeneous multinational NEC environment

An IoT enabled system for marine data acquisition and cartography

Traditional marine monitoring systems such as oceanographic and hydrographic re- search vessels use either wireless sensor networks with a limited coverage, or expensive satellite communication that is not suitable for small and mid-sized vessels. This the- sis proposes an Internet of Marine Things data acquisition and cartography system in the marine environment using Very High Frequency (VHF) available on the majority of ships. The proposed system is equipped with sensors such as sea depth, tempera- ture, wind speed and direction, and the collected data is sent through a Ship Ad-hoc Network (SANET) to 5G edge clouds connected to sink/base station nodes on shore. The sensory data is ultimately aggregated at a central cloud on the internet to produce up to date cartography systems. Several observations and challenges unique to the marine environment have been discussed and feed into the solutions presented. We have investigated the application of appropriate data quantization and compression techniques to the marine sensor data collected in order to reduce the size of transmit- ted data and achieve better transmission efficiency. The impact of marine sparsity on the network is examined and a marine Mobile Ad-hoc/Delay Tolerant hybrid routing protocol (MADNET) is proposed to switch automatically between Mobile Ad-hoc Network (MANET) and Delay Tolerant Network (DTN) routing according to the network connectivity. The low rate data transmission offered by VHF radio has been investigated in terms of the network bottlenecks and the data collection rate achiev- able near the sinks. A sensory data management and transmission approach has also been proposed at the 5G network core using Information Centric Networks (ICN) aimed at providing efficient and duplicate less transmission of marine sensory read- ings from the base station/sink nodes towards the central cloud. Therefore, SANETs are realized as part of a 5G infrastructure for marine environment monitoring, paving the way to the Internet of Marine Things (IoMaT)

Fighting the network: MANET management in support of littoral operations

Advances in computer processing and communications capabilities have contributed to the recent explosion of mesh network technologies. These technologies’ operational benefits are of particular interest for those operating in the littorals. The dynamic complexities of the littorals force tactical decision-makers to adapt to a constantly changing battlespace in a constrained temporal and spatial environment. Ongoing research into the integration of unmanned systems and sensors as mobile ad-hoc network (MANET) nodes highlights the significant potential to improve situational awareness and force efficiency in the littoral environment. However, difficulties associated with tactical network operations and management make the littorals particularly challenging. There remains a need for a unified approach to managing these networks in a coherent and effective manner. The complexity of the littorals emphasizes the inherent interconnectedness of MANET management and command and control (C2). As a result, new and innovative approaches to C2 are also required. This thesis explores the value of modern network management systems as they contribute to the richness of the human-network interface, as well as the integration of network management and maneuver at the tactical level. The result is a proposal for a novel framework for littoral MANET management and C2 as a corollary of cyber-physical maneuver.http://archive.org/details/fightingnetworkm1094548561Outstanding ThesisLieutenant, United States NavyApproved for public release; distribution is unlimited

Delay tolerant network for Navy scenarios: quality-based approach

Mestrado em Engenharia Eletrónica e TelecomunicaçõesThe navy operations involve several participants that work between them with common objectives and usually under challenged communication conditions. There are natural constrains that are imposed by the operation environment, e.g. hilly terrains. There are also artificial constrains that are created by enemy elements which force conditions to affect the navy operation (or other military forces), e.g. intentional jamming. The military often uses proprietary devices to communicate between them. Despite of the effectiveness of these devices, they are expensive and usually offer a limited range of services. However, the recent technological advances allow the proliferation of several mobile devices with wireless communication capabilities and with the value to easily insert new features, but these devices are still not prepared to military networks in terms of communication. Thus, this dissertation proposes to use Delay Tolerant Networks (DTNs) with a new routing protocol Quality-PRoPHET (Q-PRoPHET) able to measure the quality of the wireless links and route the information using the connections with best quality, where the probability of transmission is higher. The Q-PRoPHET uses a quality function to evaluate the quality of the connections and a transitive property to route through multiple hops. This algorithm was implemented in IBR-DTN and it was evaluated in three scenarios that emulate three scenarios observed during the navy tactical operations. Two of these scenarios were tested inside a building and the last one was tested in an external environment using real mobility of the nodes. The obtained results show that Q-PRoPHET has better performance than PRoPHET in terms of delivery ratio, endto-end delay and packets transmission, which are critical parameters for the communication in navy operations.As operações da marinha envolvem vários intervenientes que trabalham entre si com objetivos comuns e frequentemente sob condições de comunicação desafiadoras. Existem constrangimentos naturais que são impostos pelo ambiente da operação, por exemplo, geografia acidentada do terreno. Existem também constrangimentos artificiais que são criados por elementos hostis que forçam condições de modo a prejudicar as operações da marinha (ou outras equipas militares), por exemplo, criação de interferência intencional. Os militares geralmente usam equipamentos de comunicação proprietários para comunicar entre si. Apesar da eficácia destes equipamentos, eles são caros e normalmente oferecem uma gama de serviços limitada. Contudo, os recentes avanços tecnológicos permitiram a proliferação de muitos dispositivos portáteis com capacidade de comunicação sem fios e com o valor de acrescentar novas funcionalidades de formas muito simples, mas estes dispositivos ainda não estão adaptados para as redes militares em termos de comunicação. Esta dissertação propõe usar Redes Tolerantes a Atrasos (DTNs) com um novo protocolo de encaminhamento QualityPRoPHET (Q-PRoPHET) capaz de medir a qualidade das ligações sem-fios e encaminhar a informação pelas ligações de melhor qualidade, onde a probabilidade de sucesso da transmissão é maior. O Q-PRoPHET usa uma função de qualidade para avaliar a qualidade das ligações e uma propriedade transitiva para encaminhamento a múltiplos saltos. Este algoritmo foi implementado no IBR-DTN e foi avaliado em três cenários que emulam três cenários observados durante operações táticas da Marinha. Dois destes cenários foram testados dentro de um edifício e o último foi testado em ambiente exterior, recorrendo a mobilidade real dos nós. Os resultados obtidos mostram que o Q-PRoPHET tem melhor desempenho que o PRoPHET em termos de taxa de entrega, tempo de entrega e transmissão de pacotes, que são parâmetros críticos para as comunicações das operações da marinha

H3N - Analysewerkzeuge für hybride Wegewahl in heterogenen, unterbrechungstoleranten Ad-Hoc-Netzen für Rettungskräfte

Rettungskräfte müssen unter widrigen Bedingungen zuverlässig kommunizieren können, um in Rettungseinsätzen effizient arbeiten zu können und somit Leben zu retten. Idealerweise ist dazu ein selbstorganisiertes Ad-Hoc-Netz notwendig, weil die Kommunikationsinfrastruktur ggf. beschädigt oder überlastet sein kann. Um die geforderte Robustheit der Kommunikation auch in Szenarien mit größeren zu überbrückenden Entfernungen zu gewährleisten, werden zusätzlich Mechanismen benötigt, die eine Unterbrechungstoleranz ermöglichen. Verzögerungstolerante Netze (engl. Delay Tolerant Networks, kurz: DTN) stellen solche Mechanismen bereit, erfordern aber zusätzliche Verzögerungen, die für Rettungskommunikation nachteilig sind. Deshalb werden intelligente hybride Wegewahlverfahren benötigt, um die Verzögerung durch DTN-Mechanismen zu begrenzen. Außerdem sollten entsprechende Verfahren heterogene Netze unterstützen. Das ermöglicht zusätzlich eine effizientere Weiterleitung durch die Nutzung von Geräten mit unterschiedlichen Kommunikationstechnologien und damit auch Reichweiten. Um solche Systeme und die dafür benötigten Kommunikationsprotokolle zu entwickeln, werden verschiedene Analysewerkzeuge genutzt. Dazu gehören analytische Modelle, Simulationen und Experimente auf der Zielsystemhardware. Für jede Kategorie gibt es verschiedene Werkzeuge und Frameworks, die sich auf unterschiedliche Aspekte fokussieren. Dadurch unterstützen diese herkömmlichen Analysemethoden jedoch meistens nur einen der oben genannten Punkte, während die Untersuchung von hybriden und/oder heterogenen Ansätzen und Szenarien nicht ohne weiteres möglich ist. Im Falle von Rettungskräften kommt hinzu, dass die charakteristischen Merkmale hinsichtlich der Bewegung der Knoten und des erzeugten Datenverkehrs während eines Einsatzes ebenfalls nicht modelliert werden können. In dieser Arbeit werden deshalb verschiedene Erweiterungen zu existierenden Analysewerkzeugen sowie neue Werkzeuge zur Analyse und Modelle zur Nachbildung realistischer Rettungsmissionen untersucht und entwickelt. Ziel ist es, die Vorteile existierender Werkzeuge miteinander zu kombinieren, um ganzheitliche, realitätsnahe Untersuchungen von hybriden Protokollen für heterogene Netze zu ermöglichen. Die Kombination erfolgt in Form von gezielten Erweiterungen und der Entwicklung ergänzender komplementärer Werkzeuge unter Verwendung existierender Schnittstellen. Erste Ergebnisse unter Verwendung der entwickelten Werkzeuge zeigen Verbesserungspotentiale bei der Verwendung traditioneller Protokolle und erlauben die Bewertung zusätzlicher Maßnahmen, um die Kommunikation zu verbessern. Szenarien zur Kommunikation von Rettungskräften werden dabei als ein Beispiel verwendet, die Tools sind jedoch nicht auf die Analyse dieses Anwendungsfalls beschränkt. Über die reine Analyse verschiedener existierender Ansätze hinaus bildet die entwickelte Evaluationsumgebung eine Grundlage für die Entwicklung und Verifikation von neuartigen hybriden Protokollen für die entsprechenden Systeme.Communication between participating first responders is essential for efficient coordination of rescue missions and thus allowing to save human lives. Ideally, ad hoc-style communication networks are applied to this as the first responders cannot rely on infrastructure-based communication for two reasons. First, the infrastructure could be damaged by the disastrous event or not be available for economic reasons. Second, even if public infrastructure is available and functional, it might be overloaded by users. To guarantee the robustness and reliability requirements of first responders, the Mobile Ad Hoc Networks (MANETs) have to be combined with an approach to mitigate intermittent connectivity due to otherwise limited connectivity. Delay Tolerant Networks (DTNs) provide such a functionality but introduce additional delay which is problematic. Therefore, intelligent hybrid routing approaches are required to limit the delay introduced by DTN mechanisms. Besides that, the approach should be applicable to heterogeneous networks in terms of communication technologies and device capabilities. This is required for cross multi-agency and volunteer communication but also enables the opportunistic exploitation of any given communication option. To evaluate such systems and develop the corresponding communication protocols, various tools for the analysis are available. This includes analytical models, simulations and real-world experiments on target hardware. In each category a wide set of tools is available already. However, each tool is focused on specific aspects usually and thus does not provide methods to analyze hybrid approaches out of the box. Even if the tools are modular and allow an extension, there are often other tools that are better suited for partial aspects of hybrid systems. In addition to this, few tools exist to model the characteristics of first responder networks. Especially the generalized movement during missions and the generated data traffic are difficult to model and integrate into analyses. The focus of this project is therefore to develop selected extensions to existing analysis and simulation tools as well as additional tools and models to realistically capture the characteristics of first responder networks. The goal is to combine the advantages of existing specialized simulation tools to enable thorough evaluations of hybrid protocols for heterogeneous networks based on realistic assumptions. To achieve this, the tools are extended by specifically designing tools that enable the interaction between tools and new tools that complement the existing analysis capabilities. First results obtained via the resulting toolbox clearly indicate further research directions as well as a potential for protocol enhancements. Besides that, the toolbox was used to evaluate various methods to enhance the connectivity between nodes in first responder networks. First responder scenarios are used as an example here. The toolbox itself is however not limited to this use case. In addition to the analysis of existing approaches for hybrid and heterogeneous networks, the developed toolbox provides a base framework for the development and verification of newly developed protocols for such use cases

2020 NASA Technology Taxonomy

This document is an update (new photos used) of the PDF version of the 2020 NASA Technology Taxonomy that will be available to download on the OCT Public Website. The updated 2020 NASA Technology Taxonomy, or "technology dictionary", uses a technology discipline based approach that realigns like-technologies independent of their application within the NASA mission portfolio. This tool is meant to serve as a common technology discipline-based communication tool across the agency and with its partners in other government agencies, academia, industry, and across the world

Towards efficacy and efficiency in sparse delay tolerant networks

The ubiquitous adoption of portable smart devices has enabled a new way of communication via Delay Tolerant Networks (DTNs), whereby messages are routed by the personal devices carried by ever-moving people. Although a DTN is a type of Mobile Ad Hoc Network (MANET), traditional MANET solutions are ill-equipped to accommodate message delivery in DTNs due to the dynamic and unpredictable nature of people\u27s movements and their spatio-temporal sparsity. More so, such DTNs are susceptible to catastrophic congestion and are inherently chaotic and arduous. This manuscript proposes approaches to handle message delivery in notably sparse DTNs. First, the ChitChat system [69] employs the social interests of individuals participating in a DTN to accurately model multi-hop relationships and to make opportunistic routing decisions for interest-annotated messages. Second, the ChitChat system is hybridized [70] to consider both social context and geographic information for learning the social semantics of locations so as to identify worthwhile routing opportunities to destinations and areas of interest. Network density analyses of five real-world datasets is conducted to identify sparse datasets on which to conduct simulations, finding that commonly-used datasets in past DTN research are notably dense and well connected, and suggests two rarely used datasets are appropriate for research into sparse DTNs. Finally, the Catora system is proposed to address congestive-driven degradation of service in DTNs by accomplishing two simultaneous tasks: (i) expedite the delivery of higher quality messages by uniquely ordering messages for transfer and delivery, and (ii) avoid congestion through strategic buffer management and message removal. Through dataset-driven simulations, these systems are found to outperform the state-of-the-art, with ChitChat facilitating delivery in sparse DTNs and Catora unencumbered by congestive conditions --Abstract, page iv