6,543 research outputs found
Avaliação das propostas de integração IP sobre ATM
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.ATM (Asynchronous Transfer Mode) é uma das tecnologias de rede de alta velocidade mais adotada nos dias atuais, sendo que um dos principais diferenciais desta tecnologia é o provimento de Qualidade de Serviço. Atualmente, a tecnologia ATM deve conviver com o protocolo IP, devido principalmente ao grande volume de aplicações. Existem algumas alternativas em termos de integração do IP com ATM, por exemplo IPOA (Internet Protocol Over ATM), LANE (Lan Emulation), MPOA (MultProtocol Over ATM) e MPLS (MultProtocol Label Switch). Este trabalho apresenta estas propostas de integração IP sobre ATM, fazendo também uma análise comparativa. Outra contribuição deste trabalho é a definição de linhas guias para a seleção de uma destas opções de integração de IP sobre ATM durante o projeto de uma rede
Estimating Dynamic Traffic Matrices by using Viable Routing Changes
No full textAbstract: In this paper we propose a new approach for dealing with the ill-posed nature of traffic matrix estimation. We present three solution enhancers: an algorithm for deliberately changing link weights to obtain additional information that can make the underlying linear system full rank; a cyclo-stationary model to capture both long-term and short-term traffic variability, and a method for estimating the variance of origin-destination (OD) flows. We show how these three elements can be combined into a comprehensive traffic matrix estimation procedure that dramatically reduces the errors compared to existing methods. We demonstrate that our variance estimates can be used to identify the elephant OD flows, and we thus propose a variant of our algorithm that addresses the problem of estimating only the heavy flows in a traffic matrix. One of our key findings is that by focusing only on heavy flows, we can simplify the measurement and estimation procedure so as to render it more practical. Although there is a tradeoff between practicality and accuracy, we find that increasing the rank is so helpful that we can nevertheless keep the average errors consistently below the 10% carrier target error rate. We validate the effectiveness of our methodology and the intuition behind it using commercial traffic matrix data from Sprint's Tier-1 backbon
IMS: The New Generation of Internet-Protocol-Based Multimedia Services
No full textLegacy networks, both fixed and mobile, which were originally designed for voice communications, are progressively migrating to new infrastructures that promise to revolutionize the services offered. In this paper, we will cover this new generation of personal communication services, with an emphasis on the family of Internet protocol (IP)-based multimedia subsystem (IMS)-aided infrastructure that relies on the session initiation protocol (SIP). As a benefit, the end users will enjoy a new generation of personal communications services that are accessible anywhere and anytime. These services are timedia subsystem (IMS)-aided infrastructure that relies on the directly related to the end users rather than to their diverse devices. It is anticipated that the new deployments of next-of the IMS technology. generation networks (all-IP based) will accelerate the adoptio
Perceptions of intellectual property: a review
No full textIn “The right to good ideas: patents and the poor”, The Economist depicts two driving forces in the contemporary discourse on IP and globalization. The one is interested in advancing the knowledge economy, an approach based on the belief that knowledge is the driving factor behind economic growth. The other resides on a belief that IP is a major means to advance the process of globalization. While the former is strongly motivated by new economic growth theory, as for example advanced by Stanford professor Paul Romer, the latter is based on typical anti-globalization arguments, such as for example the position that the IP system helps multinational companies to build up monopolies to the detriment of the poor, drives small and medium-sized enterprises (SMEs) and local business in developing countries out of business and increases prices for consumer products, be they pharmaceuticals or software. The purpose of this review is to help understand the current discourse on intellectual property, to grasp underlying themes, assumptions and connotations associated with the term “IP”, so as to identify paths leading to a more comprehensive understanding of IP and the opportunities and pitfalls it may provide
Converged IP-over-standard ethernet progress control networks for hydrocarbon process automation applications controllers
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The maturity level of Internet Protocol (IP) and the emergence of standard Ethernet interfaces of Hydrocarbon Process Automation Application (HPAA) present a real opportunity to combine independent industrial applications onto an integrated IP based network platform. Quality of Service (QoS) for IP over Ethernet has the strength to regulate traffic mix and support timely delivery. The combinations of these technologies lend themselves to provide a platform to support HPAA applications across Local Area Network (LAN) and Wide Area Network (WAN) networks. HPAA systems are composed of sensors, actuators, and logic solvers networked together to form independent control system network platforms. They support hydrocarbon plants operating under critical conditions that — if not controlled — could become dangerous to people, assets and the environment. This demands high speed networking which is triggered by the need to capture data with higher frequency rate at a finer granularity. Nevertheless, existing HPAA network infrastructure is based on unique autonomous systems, which has resulted in multiple, parallel and separate networks with limited interconnectivity supporting different functions. This created increased complexity in integrating various applications and resulted higher costs in the technology life cycle total ownership. To date, the concept of consolidating HPAA into a converged IP network over standard Ethernet has not yet been explored. This research aims to explore and develop the HPAA Process Control Systems (PCS) in a Converged Internet Protocol (CIP) using experimental and simulated networks case studies. Results from experimental and simulation work showed encouraging outcomes and provided a good argument for supporting the co-existence of HPAA and non-HPAA applications taking into consideration timeliness and reliability requirements. This was achieved by invoking priority based scheduling with the highest priority being awarded to PCS among other supported services such as voice, multimedia streams and other applications. HPAA can benefit from utilizing CIP over Ethernet by reducing the number of interdependent HPAA PCS networks to a single uniform and standard network. In addition, this integrated infrastructure offers a platform for additional support services such as multimedia streaming, voice, and data. This network‐based model manifests itself to be integrated with remote control system platform capabilities at the end user's desktop independent of space and time resulting in the concept of plant virtualization
Efficient Learning of Communication Profiles from IP Flow Records
No full textThe task of network traffic monitoring has evolved drastically with the ever-increasing amount of data flowing in large scale networks. The automated analysis of this tremendous source of information often comes with using simpler models on aggregated data (e.g. IP flow records) due to time and space constraints. A step towards utilizing IP flow records more effectively are stream learning techniques. We propose a method to collect a limited yet relevant amount of data in order to learn a class of complex models, finite state machines, in real-time. These machines are used as communication profiles to fingerprint, identify or classify hosts and services and offer high detection rates while requiring less training data and thus being faster to compute than simple models.Accepted author manuscriptCyber Securit
First report of Metarhizium anisopliae IP 46 pathogenicity in adult Anopheles gambiae s.s. and An. arabiensis (Diptera; Culicidae).
No full textThe entomopathogenic fungus Metarhizium anisopliae isolate IP 46, originating from a soil sample collected in 2001 in the Cerrado of Central Brazil, was tested for its ability to reduce the survival of adult male and female Anopheles gambiae s.s. and An. arabiensis mosquitoes. A 6-h exposure to the fungus coated on test paper at a concentration of 3.3 x 106 conidia cm-2 reduced the daily survival of both mosquito species (HR = 3.14, p < 0.001), with higher risk of dying in An. gambiae s.s relative to An. arabiensis (HR = 1.38, p < 0.001). Fungal sporulation was observed in >95% of mosquito cadavers in the treatment groups. The results indicate that M. anisopliae IP 46 has the potential to be a bio-control agent for African malaria vector species, and is a suitable candidate for further research and development
Scalable QoS-aware Mobility for Future Mobile Operators
No full textTelecom operators and Internet service providers
are heading for a new shift in communications
paradigms. The forthcoming convergence
of cellular and wireless data networks is often
manifested in an “all IP approach” in which all
communications are based on an end-to-end IP
protocol framework. The approach to network
design becomes user and service-centered, so
that continuous reachability of mobile users and
sustained communication capabilities are default
requirements for a prospective architecture. In
this article, we describe a network architecture
which is able to provide seamless communication
mobility, triggered either by the user or by the
network, across multiple technologies. The architecture
allows for media independent handovers
and supports optimized mobility and resource
management functions. The main focus of the
article is on major technical highlights of mobility
and quality-of-service (QoS) management subsystems
for converged networks.Publicad
Aperfeiçoamento do desempenho do TCP em links assimétricos via políticas de escalonamento de filas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.O objetivo deste trabalho é apresentar uma proposta de melhoria a problemas de desempenho do TCP, que ocorrem devido aos efeitos da assimetria. Estes problemas acontecem em redes de acesso assimétricas, causando degradação no desempenho final do TCP, os quais ocorrem devido as imperfeições e variações no retorno dos pacotes de confirmação, Acknowlegement, enviados pela estação cliente em resposta aos pacotes de dados recebidos da estação servidora. Este trabalho detalha algumas soluções a este problema, os quais usam técnicas locais de camada de rede. Como resultado de nossa pesquisa apresentamos uma proposta baseada no aperfeiçoamento e combinação de algumas destas técnicas, e cujos resultados obtidos analisamos através de simulação de modelos
Malicious IP Address Prediction
No full textabstract: IP blacklisting is a popular technique to bolster an enterprise's security, where access to and from designated IP addresses is explicitly restricted. The fundamental idea behind blacklists is to continually add IP addresses that reputable entities, such as security researchers, have labeled as malicious to the list. Currently IP blacklisting is a reactive method, where malicious IP addresses are identified after their engagement in malicious activities is detected (e.g. hosting malware samples or sending spam emails). This thesis project aims to address this issue, by laying the groundwork for a machine learning tool that proactively identifies malicious IP address. The ground truth data derives from VirusTotal, a company that synthesizes security knowledge from prominent sources, such as Symantec, Fortinet, and ESET. I passed 307,621 IP addresses found in posts on the D2web (deep and dark web) through VirusTotal. If at least one detected URL associates with the IP address and VirusTotal deems it positive, I accordingly label the IP address as positive (malicious), and negative (non-malicious) otherwise. To give some insight into the ground truth, 6,147 IP addresses were identified as positive from the original 307,621. Furthermore, in order to quantify the prediction capabilities of our models, I introduce a metric called lead time. Lead time represents the difference between the date an IP address was first seen on the D2web and its earliest date on VirusTotal. For example, if an IP address was mentioned on the D2web on 1/5/2017 and mentioned on VirusTotal on 1/25/2017, then its lead time is 20 days. After feature selection, where I handpicked features from the data mined from the D2web, I attempted various combinations of classifiers and feature sets in order to create the best model. The final machine learning models implement temporal cross validation - where I train a model on data from 1/1/2016 up until a testing month in 2017, and test on data from the testing month - with a Random Forest classifier. The following are results from a model that was tested on January 2017, which exhibits median performance among the final models. The true positive rate is 0.2558, the false positive rate is 0.3612, and the average lead time (for leading true positives) is 193 days, where the model picks up 33.33% of all leading true positives. Although the model finds a respectable number of true positives, it picks up too many false positives. Thus, my approach is ineffective at predicting malicious IP addresses in their current state, meaning additional efforts will be required to transform the current work into a viable too
- …
