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Verificação formal de protocolos de trocas justas utilizando o metodo de espaços de fitas; Formal verification of fair exchange protocols using the strand spaces method

Fabio Rogerio Piva
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/03/2009 Português
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56.1%
Os protocolos de trocas justas foram propostos como solução para o problema da troca de itens virtuais, entre duas ou mais entidades, sem que haja a necessidade de confiança entre elas. A popularização da internet criou uma crescente classe de usuários leigos que diariamente participam de transações de troca, como comercio eletrônico (e-commerce), internet banking, redes ponto-a-ponto (P2P), etc. Com tal demanda por justiça, e preciso garantir que os protocolos de trocas justas recebam a mesma atenção acadêmica dedicada aos protocolos clássicos. Neste contexto, fazem-se necessárias diretrizes de projeto, ferramentas de verificação, taxonomias de ataques e quaisquer outros artefatos que possam auxiliar na composição de protocolos sem falhas. Neste trabalho, apresentamos um estudo sobre o problema de trocas justas e o atual estado da arte das soluções propostas, bem como a possibilidade de criar, a partir de técnicas para a verificação formal e detecção de falhas em protocolos clássicos, metodologias para projeto e correção de protocolos de trocas justas; Fair exchange protocols were first proposed as a solution to the problem of exchanging digital items, between two or more entities, without forcing them to trust each other. The popularization of the internet resulted in an increasing amount of lay users...

Proposta de especificação formal em SDL de uma rede de comunicação automotiva baseada no protocolo FlexRay com geração automatica de codigo java; A proposal for a formal specification using SDL of an invehicle network based on the FlexRay protocol with automatic Java code generation

Daniel Cesar Felisberto Rezende
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/07/2009 Português
Relevância na Pesquisa
55.9%
Este trabalho apresenta uma proposta de especificação formal em SDL de uma rede de comunicação intraveicular baseada no protocolo de comunicação FlexRay com geração automática de código Java. O modelo proposto se baseia naquele apresentado na especificação padrão do protocolo FlexRay, porém algumas contribuições foram feitas a fim de gerar uma rede FlexRay funcional e executável. O modelo SDL gerado confere uma formalização comportamental ao sistema, permitindo a sua validação e a simulação de suas principais funcionalidades e casos críticos através da ferramenta SDL TAU Suite. Depois de o sistema ser modelado, simulado e validado é gerado código Java para execução do sistema criado. Para isso, foi desenvolvida uma ferramenta geradora de código Java que recebe como entrada um arquivo com as especificações em SDL e tem-se como resultado um sistema descrito em Java que faz uso de sockets para comunicação entre os processos; This work presents a proposal of formal specification using SDL for an in-vehicle network based on the FlexRay protocol with automatic generation of Java code. The proposed model is based on that presented in the standard specification of the FlexRay protocol, although some contributions were made in order to generate a functional and executable FlexRay network. The SDL model generated provides the system a behavioural formalization...

Uma abordagem cognitiva para auto-configuração de protocolos de comunicação; A cognitive approach to self-configuration of communication protocols

Neumar Costa Malheiros
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 16/05/2013 Português
Relevância na Pesquisa
66.12%
À medida que novas tecnologias de rede são desenvolvidas, torna-se mais complexa a tarefa de gerenciar os serviços e protocolos de comunicação. Diante de tal complexidade, a gerência das redes de comunicação atuais representa um grande desafio. As soluções de gerência tradicionais, com uma arquitetura centralizada, não apresentam um alto grau de escalabilidade e não são capazes de prover reconfiguração dinâmica dos protocolos de comunicação em reposta às constantes mudanças nas condições da rede. Neste trabalho, apresenta-se uma solução factível e eficaz para auto-configuração de protocolos de comunicação. Propõe-se uma abordagem cognitiva para a reconfiguração dinâmica de parâmetros de protocolos a fim de evitar a degradação de desempenho resultante de eventuais alterações nas condições da rede. O arcabouço proposto, denominado CogProt, provê, através de mecanismos de aprendizagem e decisão, o ajuste de parâmetros dos protocolos durante a operação da rede. Parâmetros de interesse são periodicamente reconfigurados de acordo com informações de monitoramento a fim de aumentar o desempenho médio do sistema como um todo. A abordagem proposta é descentralizada e pode ser aplicada no ajuste dinâmico de uma ampla variedade de protocolos em diferentes camadas da arquitetura da rede. Apresenta-se uma série de estudos de caso para ilustrar a aplicação da abordagem proposta. Estudos baseados em simulação e um experimento em um ambiente de rede real foram realizados para avaliar o desempenho do arcabouço CogProt. Os resultados demonstram a eficácia da abordagem proposta em reagir prontamente às mudanças no estado da rede e melhorar o desempenho médio dos protocolos.; As network technologies evolve...

Uma arquitetura de gerência de mobilidade para redes veiculares; An architecture for mobility management for vehicular network

Rodolfo Ipolito Meneguette
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 16/12/2013 Português
Relevância na Pesquisa
55.9%
Redes Ad Hoc Veiculares (VANETs) constituem uma subclasse das redes Ad Hoc móveis que provê uma conexão sem fio entre veículos bem como entre veículos e dispositivos de acostamento. Essas redes proveem aplicações que focam na segurança do condutor, em fornecer maior eficiência do tráfego dos veículos nas vias públicas e em trazer algum conforto e entretenimento para os passageiros ao longo de sua viagem. Algumas dessas aplicações precisam estar conectadas com a internet através de um ponto de acesso que encontra-se no acostamento, como uma torre celular ou uma torre WiFi. Essa conexão pode gerar uma sobrecarga de mensagens de controle e pode sofrer uma troca de ponto de acesso que impacta no desempenho da aplicação. Além da interface de conexão com o ponto de acesso, o veículo é equipado com várias outras interfaces de redes vinculadas a diferentes tecnologias, podendo tirar vantagens do uso simultâneo dessas diversas interfaces de rede, com isso, maximizando a vazão e diminuindo a latência. Entretanto, esse uso pode aumentar ainda mais a sobrecarga das mensagens de controle, tendo como consequencia o aumento do tempo de troca de um ponto de acesso a outro, afetando a vazão da rede e o seu desempenho. Para superar esses desafios e prover uma boa qualidade de serviço para a aplicação...

A new architecture for packet switching network protocols

Zhang, Lixia
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 135 leaves; 12121271 bytes; 12121030 bytes; application/pdf; application/pdf
Português
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55.76%
by Lixia Zhang.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.; GRSN 409705; Includes bibliographical references (leaves 131-135).

Towards a deployable framework for delegation of authority in network applications

Stockwell, Will (Will C.)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 136 p.
Português
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55.93%
The Delegation Framework is a collection of programs, network protocols and library interfaces that provide fine-grained delegation of authority to network systems. The design and implementation of the Delegation Framework focus on addressing some of the stumbling blocks that have prevented delegation systems from becoming widely deployed in real world network applications. The Delegation Framework makes it possible to integrate delegation into an existing client-server network application without modification to the network application protocol. A dynamic library interposition implementation also make it possible to integrate delegation into large classes of legacy client and service programs with minimal or no manual source code modification. An integration case study describes the process of grafting the Delegation Framework onto a simple Apache- and MySQL-based network application and analyzes the added overhead incurred by the application.; by Will Stockwell.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.; Includes bibliographical references (p. 133-136).

NUMA impact on network storage protocolsover high-speed raw Ethernet

González-Férez, Pilar; Bilas, Angelos
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/publishedVersion; info:eu-repo/semantics/bookPart; info:eu-repo/semantics/conferenceObject
Publicado em /10/2015 Português
Relevância na Pesquisa
55.84%
Current storage trends dictate placing fast storage devices in all servers and using them as a single distributed storage system. In this converged model where storage and compute resources co-exist in the same server, the role of the network is becoming more important: network overhead is becoming a main imitation to improving storage performance. In our previous work we have designed Tyche, a network protocol for converged storage that bundles multiple 10GigE links transparently and reduces protocol overheads over raw Ethernet without hardware support. However, current technology trends and server consolidation dictates building servers with large amounts of resources (CPU, memory, network, storage). Such servers need to employ Non-Uniform Memory Architectures (NUMA) to scale memory performance. NUMA introduces significant problems with the placement of data and buffers at all software levels. In this paper, we first use Tyche to examine the performance implications of NUMA servers on end-to-end network storage performance. Our results show that NUMA effects have significant negative impact and can reduce throughput by almost 2x on servers with as few as 8 cores (16 hyper-threads). Then, we propose extensions to network protocols that can mitigate this impact. We use information about the location of data...

Building a simulation toolkit for wireless mesh clusters and evaluating the suitability of different families of ad hoc protocols for the Tactical Network Topology

Karapetsas, Konstantinos
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xx, 77 p. : ill.
Português
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56.12%
Approved for public release, distribution is unlimited; Wireless mesh networking has emerged as the successor of the traditional ad hoc networks. New technological advances, the standardization of protocols and interfaces and the maturity of key components have made it possible for current mesh research groups to set goals that are really close to the world's expectations. The objective of this research is to design and implement a simulation toolkit for wireless mesh clusters that can be used as an additional performance evaluation technique for the Tactical Network Topology program of Naval Postgraduate School. This toolkit is implemented in the OPNET simulation environment and it incorporates various nodes running different ad hoc routing protocols. Furthermore, the investigation of a suitable combination of protocols for the Tactical Network Topology is achieved by creating scenarios and running a number of simulations using the mesh toolkit.; Captain, Hellenic Air Force

A design comparison between IPv4 and IPv6 in the context of MYSEA, and implementation of an IPv6 MYSEA prototype

O'Neal, Matthew R.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xiv, 69 p. : ill.
Português
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55.87%
Approved for public release, distribution is unlimited; Internet Protocol version six (IPv6), the next generation Internet Protocol, exists sparsely in today's world. However, as it gains popularity, it will grow into a vital part of the Internet and communications technology in general. Many large organizations, including the Department of Defense, are working toward deploying IPv6 in many varied applications. This thesis focuses on the design and implementation issues that accompany a migration from Internet Protocol version four (IPv4) to IPv6 in the Monterey Security Enhanced Architecture (MYSEA). The research for this thesis consists of two major parts: a functional comparison between the IPv6 and IPv4 designs, and a prototype implementation of MYSEA with IPv6. The current MYSEA prototype relies on a subset of Network Address Translation (NAT) functionality to support the network's operation; and, due to the fact that IPv6 has no native support for NAT, this work also requires the creation of a similar mechanism for IPv6. This thesis provides a preliminary examination of IPv6 in MYSEA, which is a necessary step in determining whether the new protocol will assist with or detract from the enforcement of MYSEA policies.; Ensign...

IPv6 tactical network management

Dobrydney, John F.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xviii, 203 p. : col. ill. ;
Português
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55.9%
Approved for public release, distribution unlimited; Current and emerging technologies and equipment, such as unmanned aerial vehicles, ground sensors, networked radios, operator-worn sensor vests, and nanotechnology applications offer warfighters unprecedented command and control and information detection capabilities, yet the use of this technology has not been fully realized. The current protocol, IPv4, is incapable of providing enough addresses due to a depletion of IPv4 address space. IPv6, however, offers unprecedented network support for tactical-level sensor and communications assets in terms of increased address space, Quality of Service (QoS), flexibility, and security. The Department of Defense is transitioning from IPv4 to IPv6 in order to capitalize on IPv6's expanded capabilities. However, one unresolved area is proper IPv6 network management. Currently, the majority of the configuration and operational knowledge is in the mind of a very few individuals. The expertise currently available must be developed for application by the tactical network manager operating out on the edge of the network, in order to properly administer both an IPv4/IPv6 dual stacked network during the phased protocol transition and a purely native IPv6 network. Second...

Desirable properties of a network taxonomy

McCoy, Earl E.; Carey, Bernard J.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório Formato: 39 p. : ill. ; 28 cm.
Português
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This paper reviews and analyzes the desirable properties of a computer network taxonomy from the point of view of its usefulness in a design procedure. A key factor that must be considered is that the design environment currently evolving uses functionally high level VLSI-based building blocks to construct various network architectures. This paper begins by reviewing the uses of a taxonomy in a network context, and continues with a review of specifications for network requirements. A set of hardware interconnection primitives is defined next. A review of the Anderson and Jensen taxonomy (Ander75) is then presented, with a discussion of its completeness. The main thrust of this article is given in a section of attributes of a design oriented taxonomy. Finally, extensions are proposed for fault tolerant considerations and protocols. A computer network is defined to be a hetrogeneous collection of computers and the telecommunications subsystem linking them together. Here the properties of the various network architectures are of particular interest; the 'user' computers (or processors) are considered as sources and sinks of messages being transmitted over the network. No distinction as to the geographical scope of the network is made because it does not impact the taxonomy considerations addressed here. (Author); supported by the Department of Computer Science...

Device profiling analysis in Device-Aware Network

Tsai, Shang-Yuan
Fonte: Monterey California. Naval Postgraduate School Publicador: Monterey California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xiv, 67 p. : ill. (some col.)
Português
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55.92%
Approved for public release, distribution is unlimited; As more and more devices with a variety of capabilities are Internet-capable, device independence becomes a big issue when we would like the information that we request to be correctly displayed. This thesis introduces and compares how existing standards create a profile that describes the device capabilities to achieve the goal of device independence. After acknowledging the importance of device independence, this paper utilizes the idea to introduce a Device-Aware Network (DAN). DAN provides the infrastructure support for device-content compatibility matching for data transmission. We identify the major components of the DAN architecture and issues associated with providing this new network service. A Device-Aware Network will improve the network's efficiency by preventing unusable data from consuming host and network resources. The device profile is the key issue to achieve this goal.; Captain, Taiwan Army

A formal methodology for integral security design and verification of network protocols

Diaz, Jesus; Arroyo, David; Rodriguez, Francisco B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.89%
We propose a methodology for verifying security properties of network protocols at design level. It can be separated in two main parts: context and requirements analysis and informal verification; and formal representation and procedural verification. It is an iterative process where the early steps are simpler than the last ones. Therefore, the effort required for detecting flaws is proportional to the complexity of the associated attack. Thus, we avoid wasting valuable resources for simple flaws that can be detected early in the verification process. In order to illustrate the advantages provided by our methodology, we also analyze three real protocols.

Parameterized Verification of Safety Properties in Ad Hoc Network Protocols

Delzanno, Giorgio; Sangnier, Arnaud; Zavattaro, Gianluigi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/08/2011 Português
Relevância na Pesquisa
55.94%
We summarize the main results proved in recent work on the parameterized verification of safety properties for ad hoc network protocols. We consider a model in which the communication topology of a network is represented as a graph. Nodes represent states of individual processes. Adjacent nodes represent single-hop neighbors. Processes are finite state automata that communicate via selective broadcast messages. Reception of a broadcast is restricted to single-hop neighbors. For this model we consider a decision problem that can be expressed as the verification of the existence of an initial topology in which the execution of the protocol can lead to a configuration with at least one node in a certain state. The decision problem is parametric both on the size and on the form of the communication topology of the initial configurations. We draw a complete picture of the decidability and complexity boundaries of this problem according to various assumptions on the possible topologies.; Comment: In Proceedings PACO 2011, arXiv:1108.1452

Valid formulas, games and network protocols

Krivine, Jean-Louis; Legrandgérard, Yves
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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55.96%
We describe a remarkable relation between the notion of valid formula of predicate logic and the specification of network protocols. We give several examples such as the acknowledgement of one packet or of a sequence of packets. We show how to specify the composition of protocols.; Comment: 12 pages

Findings of a comparison of five filing protocols

McFaul, R. Elayne
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
55.99%
Filing protocols are essential for the management and dissemination of shared information within computer systems. This is a survey of the current state of the art in filing protocols. Five popular filing protocols were selected and subjected to a rigorous comparison. FTAM, FTP, UNIX rep, XNS Filing, and NFS are compared in the following areas: exported interface, concurrency control, access control, error recovery, and performance. The coverage of background material includes a taxonomy and a brief history of filing protocols.

Performance comparison between Ad Hoc On Demand Distance Vector and Dynamic Source Routing Protocols with security encryption using OPNET

Jafferi, Jaseem
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
56.14%
Application for wireless networking has been evolving rapidly and is becoming an integral part in our everyday life. Also with the recent performance advancement in wireless communication technologies, mobile wireless ad-hoc networks has been used in many areas such as military, health and commercial applications. Mobile ad hoc networks utilize radio waves and microwaves to maintain communication channel between computers. 802.11 (Wi-Fi) is the pre-eminent technology for building general purpose wireless networks. Mobile ad-hoc networking (MANET) utilize the Internet Protocol (IP) suite and aims at supporting robust and efficient operation by incorporating routing functionality into the mobile nodes. MANET is among one of the wireless networks that uses 802.11 to transmit data from the source to the destination. Since MANET is used in applications like defense, security is of vital importance due to its wireless nature. Wireless networks are vulnerable to attacks like eavesdropping, Man-In-The-Middle-Attack (MITM), hijacking, and so are MANETs. A malicious node can get within the wireless range of the nodes in the MANET and can disrupt the communication process. Various routing protocols have been proposed using encryption techniques to protect routing in MANETs. In this thesis...

A clustering approach in sensor network time synchronization

Krishnaram, Ramesh
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
56.06%
In recent years tremendous technological advances have led to the development of low-cost sensors capable of data processing activities. These sensor nodes are organized in to a network typically called wireless Sensor Network. WSN's are based on the principle of "Data Fusion" where the data collected from each sensor node is condensed into one meaningful result: Data Fusion is achieved by exchanging messages between the sensors. These messages are time stamped by each sensor node's local clock fuse reading. As noted in various references, Time Synchronization is a common feature used in networking in order to give the nodes a common time reference. Time Synchronization is an important middleware service in Wireless Sensor Networks, as physical time is needed to relate events to the physical world. WSN's require a great deal of synchronization accuracy so that information from many nodes can be cohesively integrated without creating time skews in the data. State-of-the-art research has been investigating the sources of error in attempting to synchronize the nodes in a network. The objective of this thesis is to define a Time Synchronization protocol for a Hierarchical Cluster Head based Wireless Sensor Network. Thus, the goals of this thesis are three fold: We first analyze the shortcomings of existing time synchronization protocols and propose a novel time synchronization protocol based on cluster tree based routing. We perform hardware-based simulation using Mica motes...

Wireless body area network platform utilizing energy-efficient routing of physiological data

Prieto, Alvaro
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
55.94%
Wireless Body Area Networks (WBANs) consist of several wireless sensors located around a human body. These sensors may measure several biological signals, movement, and temperature. Due to major improvements in power consumption and constantly shrinking devices, WBANs are becoming ubiquitous. As a side effect present because of the small form factor of these devices, the battery size is limited. While the sensors themselves may be extremely power efficient, all of the measured data must be transmitted over a much less efficient wireless link. One benefit of WBANs is that they rarely include more than a dozen wireless devices over a small area. This constraint allows for the use of routing techniques not suitable for larger wireless sensor networks(WSNs). Presented in this work is a novel global routing algorithm link-cost function to maximize network lifetime in WBANs. Also included are a basic software framework for developing WBANs, a sample Wireless Electrocardiogram (ECG) application, and a simple link cost algorithm development platform.

Rigorous specification and conformance testing techniques for network protocols, as applied to TCP, UDP, and sockets

Bishop, Steve; Fairbairn, Matthew; Norrish, Michael; Sewell, Peter; Smith, Michael; Wansbrough, Keith
Fonte: Association for Computing Machinery Inc (ACM) Publicador: Association for Computing Machinery Inc (ACM)
Tipo: Artigo de Revista Científica
Português
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66.02%
Network protocols are hard to implement correctly. Despite the existence of RFCs and other standards, implementations often have subtle differences and bugs. One reason for this is that the specifications are typically informal, and hence inevitably contain ambiguities. Conformance testing against such specifications is challenging.In this paper we present a practical technique for rigorous protocol specification that supports specification-based testing. We have applied it to TCP, UDP, and the Sockets API, developing a detailed 'post-hoc' specification that accurately reflects the behaviour of several existing implementations (FreeBSD 4.6, Linux 2.4.20-8, and Windows XP SP1). The development process uncovered a number of differences between and infelicities in these implementations.Our experience shows for the first time that rigorous specification is feasible for protocols as complex as TCP. We argue that the technique is also applicable 'pre-hoc', in the design phase of new protocols. We discuss how such a design-for-test approach should influence protocol development, leading to protocol specifications that are both unambiguous and clear, and to high-quality implementations that can be tested directly against those specifications.