Highly intensive data dissemination in complex networks

This paper presents a study on data dissemination in unstructured Peer-to-Peer (P2P) network overlays. The absence of a structure in unstructured overlays eases the network management, at the cost of non-optimal mechanisms to spread messages in the network. Thus, dissemination schemes must be employed that allow covering a large portion of the network with a high probability (e.g.~gossip based approaches). We identify principal metrics, provide a theoretical model and perform the assessment evaluation using a high performance simulator that is based on a parallel and distributed architecture. A main point of this study is that our simulation model considers implementation technical details, such as the use of caching and Time To Live (TTL) in message dissemination, that are usually neglected in simulations, due to the additional overhead they cause. Outcomes confirm that these technical details have an important influence on the performance of dissemination schemes and that the studied schemes are quite effective to spread information in P2P overlay networks, whatever their topology. Moreover, the practical usage of such dissemination mechanisms requires a fine tuning of many parameters, the choice between different network topologies and the assessment of behaviors such as free riding. All this can be done only using efficient simulation tools to support both the network design phase and, in some cases, at runtime

Cost-effective broadcast for fully decentralized peer-to-peer networks

Fully unstructured and decentralized peer-to-peer networks such as Gnutella are appealing for a variety of applications, among which file-sharing is the most prominent one. The decentralized nature of these systems provides a high degree of robustness and the ability to cope with a highly dynamic and transient network environment. However, the lack of centralized directory nodes makes the task of searching more expensive and difficult. In completely unstructured peer-to-peer networks, searching can only be realized via application-layer broadcast, where query messages are routed to every node in the network. Gnutella implements application-layer broadcast by using flooding as the underlying message routing mechanism. Flooding creates a large amount of traffic and can quickly exhaust the resources of nodes in a large network. In this paper, we explore Rumor mongering (also known as Gossip) as a more cost-effective and scalable alternative to flooding for implementing services such as searching in decentralized peer-to-peer networks. We further present a new variant of the Rumor mongering protocol, which exploits the power-law characteristics of typical peer-to-peer networks and achieves a significant further reduction in cost. (C) 2002 Elsevier Science B.V. All rights reserved

RPM: um protocolo para comunicação anônima em redes par a par (P2P)

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia de Automação e SistemasO anonimato é um preocupação crescente nos atuais sistemas baseados na Internet. As redes de anonimato tradicionais, baseadas em misturadores ou multicast, possuem limitações de confiabilidade, confidencialidade e desempenho. A ampla escala de redes P2P pode ser usada para minimizar tais limitações, mas essas redes têm de lidar com o fenômeno do churn (entrada e saída de nós na rede) e a menor confiabilidade dos nós individuais (devido ao roteamento na camada de aplicação). Esta dissertação apresenta o RPM (Random Path + Multicast), um protocolo para comunicação anônima em sistemas P2P. Além do anonimato, o RPM tem por objetivo a resistência ao churn e a redução do custo computacional normalmente associado a sistemas de anonimato. Para o seu desenvolvimento, primeiramente foi realizada uma revisão bibliográfica de grande parte da literatura referente ao assunto abordado. Posteriormente foram definidos os objetivos gerais e específicos do projeto visando definir assim sua estrutura funcional. Ao final, foram realisados diversos testes através de simulações, os quais demonstraram que o RPM atinge eficazmente seus objetivos, especialmente com respeito à resistência ao churn

Agent organization in the KP

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 181-191).In designing and building a network like the Internet, we continue to face the problems of scale and distribution. With the dramatic expansion in scale and heterogeneity of the Internet, network management has become an increasingly difficult task. Furthermore, network applications often need to maintain efficient organization among the participants by collecting information from the underlying networks. Such individual information collection activities lead to duplicate efforts and contention for network resources. The Knowledge Plane (KP) is a new common construct that provides knowledge and expertise to meet the functional, policy and scaling requirements of network management, as well as to create synergy and exploit commonality among many network applications. To achieve these goals, we face many challenging problems, including widely distributed data collection, efficient processing of that data, wide availability of the expertise, etc. In this thesis, to provide better support for network management and large-scale network applications, I propose a knowledge plane architecture that consists of a network knowledge plane (NetKP) at the network layer, and on top of it, multiple specialized KPs (spec-KPs). The NetKP organizes agents to provide valuable knowledge and facilities about the Internet to the spec-KPs. Each spec-KP is specialized in its own area of interest. In both the NetKP and the spec-KPs, agents are organized into regions based on different sets of constraints. I focus on two key design issues in the NetKP: (1) a region-based architecture for agent organization, in which I design an efficient and non-intrusive organization among regions that combines network topology and a distributed hash table; (2) request and knowledge dissemination, in which I design a robust and efficient broadcast and aggregation mechanism using a tree structure among regions.(cont.) In the spec-KPs, I build two examples: experiment management on the PlanetLab testbed and distributed intrusion detection on the DETER testbed. The experiment results suggest a common approach driven by the design principles of the Internet and more specialized constraints can derive productive organization for network management and applications.by Ji Li.Ph.D

Agent Organization in the Knowledge Plane

In designing and building a network like the Internet, we continue to face the problems of scale and distribution. With the dramatic expansion in scale and heterogeneity of the Internet, network management has become an increasingly difficult task. Furthermore, network applications often need to maintain efficient organization among the participants by collecting information from the underlying networks. Such individual information collection activities lead to duplicate efforts and contention for network resources.The Knowledge Plane (KP) is a new common construct that provides knowledge and expertise to meet the functional, policy and scaling requirements of network management, as well as to create synergy and exploit commonality among many network applications. To achieve these goals, we face many challenging problems, including widely distributed data collection, efficient processing of that data, wide availability of the expertise, etc.In this thesis, to provide better support for network management and large-scale network applications, I propose a knowledge plane architecture that consists of a network knowledge plane (NetKP) at the network layer, and on top of it, multiple specialized KPs (spec-KPs). The NetKP organizes agents to provide valuable knowledge and facilities about the Internet to the spec-KPs. Each spec-KP is specialized in its own area of interest. In both the NetKP and the spec-KPs, agents are organized into regions based on different sets of constraints. I focus on two key design issues in the NetKP: (1) a regionbased architecture for agent organization, in which I design an efficient and non-intrusive organization among regions that combines network topology and a distributed hash table; (2) request and knowledge dissemination, in which I design a robust and efficient broadcast and aggregation mechanism using a tree structure among regions. In the spec-KPs, I build two examples: experiment management on the PlanetLab testbed and distributed intrusion detection on the DETER testbed. The experiment results suggest a common approach driven by the design principles of the Internet and more specialized constraints can derive productive organization for network management and applications