A lightweight distributed super peer election algorithm for unstructured dynamic P2P systems

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de ComputadoresNowadays with the current growth of information exchange, and the increasing mobility of devices, it becomes essential to use technology to monitor this development. For that P2P networks are used, the exchange of information between agencies is facilitated, these now being applied in mobile networks, including MANETs, where they have special features such as the fact that they are semi-centralized, where it takes peers more ability to make a greater role in the network. But those peer with more capacity, which are used in the optimization of various parameters of these systems, such as optimization\to research, are difficult to identify due to the fact that the network does not have a fixed topology, be constantly changing, (we like to go online and offline, to change position, etc.) and not to allow the exchange of large messages. To this end, this thesis proposes a distributed election algorithm of us greater capacity among several possible goals, enhance research in the network. This includes distinguishing characteristics, such as election without global knowledge network, minimal exchange of messages, distributed decision made without dependence on us and the possibility of influencing the election outcome as the special needs of the network

Conceptual development of resources discovery in the proposed hybrid P2P video streaming

We present the design of a hybrid Peer-to-Peer (P2P) system for video streaming. In this paper, we address the availability, accessibility and lookup service of files. We use the advantages of server-client business model to search and retrieve the information. We implement the base ontology of video domain repository so that the final result may be different and provide more results from the keyword search. To provide the dynamic standby peer, we use checksum value as an indicator to search an identical content in the Peer-to-Peer network. We hypothesize that, by using server-client searching in Peer-to-Peer application, we can reduce the latency lookup services, path length, peer load and network traffic

Prospects of peer-to-peer SIP for mobile operators

Tämän diplomityön tarkoituksena on esitellä kehitteillä oleva Peer-to-Peer Session Initiation Protocol (P2PSIP), jonka avulla käyttäjät voivat itsenäisesti ja helposti luoda keskenään puhe- ja muita multimediayhteyksiä vertaisverkko-tekniikan avulla. Lisäksi tarkoituksena on arvioida P2PSIP protokollan vaikutuksia ja mahdollisuuksia mobiilioperaattoreille, joille sitä voidaan pitää uhkana. Tästä huolimatta, P2PSIP:n ei ole kuitenkaan tarkoitus korvata nykyisiä puhelinverkkoja. Työn alussa esittelemme SIP:n ja vertaisverkkojen (Peer-to-Peer) periaatteet, joihin P2PSIP-protokollan on suunniteltu perustuvan. SIP mahdollistaa multimedia-istuntojen luomisen, sulkemisen ja muokkaamisen verkossa, mutta sen monipuolinen käyttö vaatii keskitettyjen palvelimien käyttöä. Vertaisverkon avulla käyttäjät voivat suorittaa keskitettyjen palvelimien tehtävät keskenään hajautetusti. Tällöin voidaan ylläpitää laajojakin verkkoja tehokkaasti ilman palvelimista aiheutuvia ylläpito-kustannuksia. Mobiilioperaattorit ovat haasteellisen tilanteen edessä, koska teleliikennemaailma on muuttumassa yhä avoimemmaksi. Tällöin operaattoreiden asiakkaille aukeaa mahdollisuuksia käyttää kilpailevia Internet-palveluja (kuten Skype) helpommin ja tulevaisuudessa myös itse muodostamaan kommunikointiverkkoja P2PSIP:n avulla. Tutkimukset osoittavat, että näistä uhista huolimatta myös operaattorit pystyvät näkemään P2PSIP:n mahdollisuutena mukautumisessa nopeasti muuttuvan teleliikennemaailman haasteisiin. Nämä mahdollisuudet sisältävät operaattorin oman verkon optimoinnin lisäksi vaihtoehtoisten ja monipuolisempien palveluiden tarjoamisen asiakkailleen edullisesti. Täytyy kuitenkin muistaa, että näiden mahdollisuuksien toteuttamisten vaikutusten ei tulisi olla ristiriidassa operaattorin muiden palveluiden kanssa. Lisäksi tulisi muistaa, että tällä hetkellä keskeneräisen P2PSIP-standardin lopullinen luonne ja ominaisuudet voivat muuttaa sen vaikutuksia.The purpose of this thesis is to present the Peer-to-Peer Session Initiation Protocol (P2PSIP) being developed. In addition, the purpose of this thesis is to evaluate the impacts and prospects of P2PSIP to mobile operators, to whom it can be regarded as a threat. In P2PSIP, users can independently and easily establish voice and other multimedia connections using peer-to-peer (P2P) networking. However, P2PSIP is not meant to replace the existing telephony networks of the operators. We start by introducing the principles of SIP and P2P networking that the P2PSIP is intended to use. SIP enables to establish, terminate and modify multimedia sessions, but its versatile exploitation requires using centralized servers. By using P2P networking, users can decentralize the functions of centralized servers by performing them among themselves. This enables to maintain large and robust networks without maintenance costs resulted of running such centralized servers. Telecommunications market is transforming to a more open environment, where mobile operators and other service providers are challenged to adapt to the upcoming changes. Subscribers have easier access to rivalling Internet-services (such as Skype) and in future they can form their own communication communities by using P2PSIP. The results show that despite of these threats, telecom operators can find potential from P2PSIP in concurrence in adaptation to the challenges of the rapidly changing telecom environment. These potential roles include optimization of the network of the operator, but as well roles to provide alternative and more versatile services to their subscribers at low cost. However, the usage of P2PSIP should not conflict with the other services of the operator. Also, as P2PSIP is still under development, its final nature and features may change its impacts and prospects

Peer-to-Peer Networks and Computation: Current Trends and Future Perspectives

This research papers examines the state-of-the-art in the area of P2P networks/computation. It attempts to identify the challenges that confront the community of P2P researchers and developers, which need to be addressed before the potential of P2P-based systems, can be effectively realized beyond content distribution and file-sharing applications to build real-world, intelligent and commercial software systems. Future perspectives and some thoughts on the evolution of P2P-based systems are also provided

Provision, discovery and development of ubiquitous services and applications

Ph.DDOCTOR OF PHILOSOPH

Large-Scale Distributed Coalition Formation

The CyberCraft project is an effort to construct a large scale Distributed Multi-Agent System (DMAS) to provide autonomous Cyberspace defense and mission assurance for the DoD. It employs a small but flexible agent structure that is dynamically reconfigurable to accommodate new tasks and policies. This document describes research into developing protocols and algorithms to ensure continued mission execution in a system of one million or more agents, focusing on protocols for coalition formation and Command and Control. It begins by building large-scale routing algorithms for a Hierarchical Peer to Peer structured overlay network, called Resource-Clustered Chord (RC-Chord). RC-Chord introduces the ability to efficiently locate agents by resources that agents possess. Combined with a task model defined for CyberCraft, this technology feeds into an algorithm that constructs task coalitions in a large-scale DMAS. Experiments reveal the flexibility and effectiveness of these concepts for achieving maximum work throughput in a simulated CyberCraft environment

Effective techniques for detecting and locating traffic differentiation in the internet

Orientador: Elias P. Duarte Jr.Coorientador: Luis C. E. BonaTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa : Curitiba, 24/09/2019Inclui referências: p. 115-126Área de concentração: Ciência da ComputaçãoResumo: A Neutralidade da Rede torna-se cada vez mais relevante conforme se intensifica o debate global e diversos governos implementam regulações. Este princípio diz que todo tráfego deve ser processado sem diferenciação, independentemente da origem, destino e/ou conteúdo. Práticas de diferenciação de tráfego (DT) devem ser transparentes, independentemente de regulações, pois afetam significativamente usuários finais. Assim, é essencial monitorar DT na Internet. Várias soluções já foram propostas para detectar DT. Essas soluções baseiam-se em medições de rede e inferência estatística. Porém, existem desafios em aberto. Esta tese tem três objetivos principais: (i) consolidar o estado da arte referente ao problema de detectar DT; (ii) investigar a DT em contextos ainda não explorados, especificamente a Internet das Coisas (IoT); e (iii) propor novas soluções para detecção de DT que solucionem alguns dos desafios em aberto, em particular localizar a fonte de DT. Primeiramente descrevemos o atual estado da arte, incluindo várias soluções de detecção de DT. Também propomos uma taxonomia para os diferentes tipos de DT e de detecção, e identificamos desafios em aberto. Em seguida, avaliamos o impacto da DT na IoT, simulando DT de diferentes padrões de tráfego IoT. Resultados mostram que mesmo uma priorização pequena pode ter um impacto significativo no desempenho de dispositivos de IoT. Propomos então uma solução para detectar DT na Internet, que baseia-se em uma nova estratégia que combina diversas métricas para detectar tipos diferente de DT. Resultados de simulação mostram que esta estratégia é capaz de detectar DT em diversas situações. Em seguida, propomos um modelo geral para monitoramento contínuo de DT na Internet, que se propõe a unificar as soluções atuais e futuras de detecção de DT, ao mesmo tempo que tira proveito de tecnologias atuais e emergentes. Neste contexto, uma nova solução para identificar a fonte de DT na Internet é proposta. O objetivo desta proposta é tanto viabilizar a implementação do nosso modelo geral quanto solucionar o problema de localizar DT. A proposta tira proveito de propriedades de roteamento da Internet para identificar em qual Sistema Autônomo (AS) DT acontece. Medições de vários pontos de vista são combinadas, e a fonte de DT é inferida com base nos caminhos em nível de AS entre os pontos de medição. Para avaliar esta proposta, primeiramente executamos experimentos para confirmar que rotas na Internet realmente apresentam as propriedades requeridas. Diversas simulações foram então executadas para avaliar a eficiência da proposta de localização de DT. Resultados mostram que em diversas situações, efetuar medições a partir de poucos nodos no núcleo da Internet obtém resultados similares a efetuar medições a partir de muitos nodos na borda. Palavras-chave: Neutralidade da Rede, Diferenciação de Tráfego, Medição de Rede.Abstract: Network Neutrality is becoming increasingly important as the global debate intensifies and governments worldwide implement and withdraw regulations. According to this principle, all traffic must be processed without differentiation, regardless of origin, destination and/or content. Traffic Differentiation (TD) practices should be transparent, regardless of regulations, since they can significantly affect end-users. It is thus essential to monitor TD in the Internet. Several solutions have been proposed to detect TD. These solutions are based on network measurements and statistical inference. However, there are still open challenges. This thesis has three main objectives: (i) to consolidate the state of the art regarding the problem of detecting TD; (ii) to investigate TD on contexts not yet explored, in particular the Internet of Things (IoT); and (iii) to propose new solutions regarding TD detection that address open challenges, in particular locating the source of TD. We first describe the current state of the art, including a description of multiple solutions for detecting TD. We also propose a taxonomy for the different types of TD and the different types of detection, and identify open challenges. Then, we evaluate the impact of TD on IoT, by simulating TD on different IoT traffic patterns. Results show that even a small prioritization may have a significant impact on the performance of IoT devices. Next, we propose a solution for detecting TD in the Internet. This solution relies on a new strategy of combining several metrics to detect different types of TD. Simulation results show that this strategy is capable of detecting TD under several conditions. We then propose a general model for continuously monitoring TD on the Internet, which aims at unifying current and future TD detection solutions, while taking advantage of current and emerging technologies. In this context, a new solution for locating the source of TD in the Internet is proposed. The goal of this proposal is to both enable the implementation of our general model and address the problem of locating TD. The proposal takes advantage of properties of Internet peering to identify in which Autonomous System (AS) TD occurs. Probes from multiple vantage points are combined, and the source of TD is inferred based on the AS-level routes between the measurement points. To evaluate this proposal, we first ran several experiments to confirm that indeed Internet routes do present the required properties. Then, several simulations were performed to assess the efficiency of the proposal for locating TD. The results show that for several different scenarios issuing probes from a few end-hosts in core Internet ASes achieves similar results than from numerous end-hosts on the edge. Keywords: Network Neutrality, Traffic Differentiation, Network Measurement

Enabling Internet-Scale Publish/Subscribe In Overlay Networks

As the amount of data in todays Internet is growing larger, users are exposed to too much information, which becomes increasingly more difficult to comprehend. Publish/subscribe systems leverage this problem by providing loosely-coupled communications between producers and consumers of data in a network. Data consumers, i.e., subscribers, are provided with a subscription mechanism, to express their interests in a subset of data, in order to be notified only when some data that matches their subscription is generated by the producers, i.e., publishers. Most publish/subscribe systems today, are based on the client/server architectural model. However, to provide the publish/subscribe service in large scale, companies either have to invest huge amount of money for over-provisioning the resources, or are prone to frequent service failures. Peer-to-peer overlay networks are attractive alternative solutions for building Internet-scale publish/subscribe systems. However, scalability comes with a cost: a published message often needs to traverse a large number of uninterested (unsubscribed) nodes before reaching all its subscribers. We refer to this undesirable traffic, as relay overhead. Without careful considerations, the relay overhead might sharply increase resource consumption for the relay nodes (in terms of bandwidth transmission cost, CPU, etc) and could ultimately lead to rapid deterioration of the system’s performance once the relay nodes start dropping the messages or choose to permanently abandon the system. To mitigate this problem, some solutions use unbounded number of connections per node, while some other limit the expressiveness of the subscription scheme. In this thesis work, we introduce two systems called Vitis and Vinifera, for topic-based and content-based publish/subscribe models, respectively. Both these systems are gossip-based and significantly decrease the relay overhead. We utilize novel techniques to cluster together nodes that exhibit similar subscriptions. In the topic-based model, distinct clusters for each topic are constructed, while clusters in the content-based model are fuzzy and do not have explicit boundaries. We augment these clustered overlays by links that facilitate routing in the network. We construct a hybrid system by injecting structure into an otherwise unstructured network. The resulting structures resemble navigable small-world networks, which spans along clusters of nodes that have similar subscriptions. The properties of such overlays make them an ideal platform for efficient data dissemination in large-scale systems. The systems requires only a bounded node degree and as we show, through simulations, they scale well with the number of nodes and subscriptions and remain efficient under highly complex subscription patterns, high publication rates, and even in the presence of failures in the network. We also compare both systems against some state-of-the-art publish/subscribe systems. Our measurements show that both Vitis and Vinifera significantly outperform their counterparts on various subscription and churn scenarios, under both synthetic workloads and real-world traces

An empirical comparison of the security and performance characteristics of topology formation algorithms for Bitcoin networks

There is an increasing demand for digital crypto-currencies to be more secure and robust to meet the following business requirements: (1) low transaction fees and (2) the privacy of users. Nowadays, Bitcoin is gaining traction and wide adoption. Many well-known businesses have begun accepting bitcoins as a means of making financial payments. However, the susceptibility of Bitcoin networks to information propagation delay, increases the vulnerability to attack of the Bitcoin network, and decreases its throughput performance. This paper introduces and critically analyses new network clustering methods, named Locality Based Clustering (LBC), Ping Time Based Approach (PTBC), Super Node Based Clustering (SNBA), and Master Node Based Clustering (MNBC). The proposed methods aim to decrease the chances of performing a successful double spending attack by reducing the information propagation delay of Bitcoin. These methods embody proximity-aware extensions to the standard Bitcoin protocol, where proximity is measured geographically and in terms of latency. We validate our proposed methods through a set of simulation experiments and the findings show how the proposed methods run and their impact in optimising the transaction propagation delay. Furthermore, these new methods are evaluated from the perspective of the Bitcoin network’s resistance to partitioning attacks. Numerical results, which are established via extensive simulation experiments, demonstrate how the extensions run and also their impact in optimising the transaction propagation delay. We draw on these findings to suggest promising future research directions for the optimisation of transaction propagation delays

A framework for the dynamic management of Peer-to-Peer overlays

Peer-to-Peer (P2P) applications have been associated with inefficient operation, interference with other network services and large operational costs for network providers. This thesis presents a framework which can help ISPs address these issues by means of intelligent management of peer behaviour. The proposed approach involves limited control of P2P overlays without interfering with the fundamental characteristics of peer autonomy and decentralised operation. At the core of the management framework lays the Active Virtual Peer (AVP). Essentially intelligent peers operated by the network providers, the AVPs interact with the overlay from within, minimising redundant or inefficient traffic, enhancing overlay stability and facilitating the efficient and balanced use of available peer and network resources. They offer an “insider‟s” view of the overlay and permit the management of P2P functions in a compatible and non-intrusive manner. AVPs can support multiple P2P protocols and coordinate to perform functions collectively. To account for the multi-faceted nature of P2P applications and allow the incorporation of modern techniques and protocols as they appear, the framework is based on a modular architecture. Core modules for overlay control and transit traffic minimisation are presented. Towards the latter, a number of suitable P2P content caching strategies are proposed. Using a purpose-built P2P network simulator and small-scale experiments, it is demonstrated that the introduction of AVPs inside the network can significantly reduce inter-AS traffic, minimise costly multi-hop flows, increase overlay stability and load-balancing and offer improved peer transfer performance