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Adaptive Routing Algorithms in Unstructured Peer-to-Peer (P2P) Systems  [PDF]
Achmad Nizar Hidayanto,,Stephane Bressan
International Journal on Computer Science and Engineering , 2011,
Abstract: There are a variety of peer-to-peer (P2P) systems for sharing documents currently available. According to their data organization, P2P systems are classified into two categories: structured andunstructured P2P systems. In structured P2P systems, peers are organized according to some mapping techniques, e.g. hashing function. Whereas in unstructured P2P system, peers are connected to each others randomly; resources are not moved to other peers but hosted on site. Unstructured P2P systems offer a more flexible and autonomous environment, as they require less control for the placement of resources and peers. This work focuses on experimenting on unstructured P2P systems. The challenge in unstructured P2P system is designing routing strategies that lead the user in finding the documents needed. Routing strategies in unstructured P2P system need to consider the dynamic aspects of P2P systems; peers are dynamic and constantly joining and leaving the system, network load changescontinuously and resources are added and removed over the time. Therefore, the routing strategy must adapt to such changes to maintain its performance. We propose routing strategies that adapt to these changes through learning mechanisms. The learning mechanisms are conducted by observing the internal and external behaviors of the system. Internal behaviors reflect the internal state of peers such as peers’ interest and collection. External behaviors reflect the external state of the system such as network load. In order to measure the performance of the proposed routing algorithms, some common performance measurements are used. These are “response time” and “number of messages generated” or what is commonly referred to as efficiency, “number of answered and satisfied queries” and the “similarity of documents” or what is commonly referred to as effectiveness of retrieval system. The experiment results show that the proposed algorithms are capable of adapting to new changes. By learning to adapt, the system maintains its performance in terms of efficiency and effectiveness. Moreover, comparison with other similar algorithms also shows the superiority of the proposed routing lgorithms. Thus, the proposed routing algorithms are good candidates for effective and efficient retrieval of documents in P2P systems.
Multi-Dimensional Range Search in Unstructured Peer-to-Peer Systems
非结构化对等计算系统中多维范围搜索

XU Lin-Hao,QIAN Wei-Ning,ZHOU Ao-Ying,
徐林昊
,钱卫宁,周傲英

软件学报 , 2007,
Abstract: It is an important problem to efficiently support similarity search for multi-dimensional data spaces in peer-to-peer (P2P) data management environment. Current unstructured P2P data sharing systems provide only a very rudimentary facility in query processing, i.e., matching-based query processing. This paper therefore presents a simple, yet effective index structure called EVARI (extended vector approximation routing index) to address the problem of multi-dimensional range search in unstructured P2P systems, by means of both data approximation and routing index techniques. With the aid of the EVARI, each peer can not only process range queries with its local dataset, but also route queries to promising peers with the desired data objects. In the proposed scheme, each peer summarizes its local content using space-partitioning technique, and exchanges the summarized information with neighboring peers to construct the EVARI. Furthermore, each peer can reconfigure its neighboring peers to keep the relevant peers nearby so as to optimize system resource configuration and improve system performance. Extensive experiments show the good performance of the proposed approach.
Survey on Search Mechanisms for Unstructured Peer-to-Peer Networks
无结构化P2P网络资源搜索机制研究综述

QIAN Ning,WU Guo-xin,
钱宁
,吴国新

计算机科学 , 2010,
Abstract: The success of file-sharing applications such as Napster and Gnutella makes Peer-to-Peer networks developing rapidly.Efficient resource discovery is the first step towards distributed resource sharing.Recently many search methods have been proposed.We gave an overview of search mechanisms for unstructured Peer-to-Peer networks in this paper.Firstly we approximately classified existing search methods based on the features of them.Then we discussed critical techniques used in these approaches in detail and co...
Anonymity in the Wild: Mixes on unstructured networks  [PDF]
Shishir Nagaraja
Computer Science , 2007,
Abstract: As decentralized computing scenarios get ever more popular, unstructured topologies are natural candidates to consider running mix networks upon. We consider mix network topologies where mixes are placed on the nodes of an unstructured network, such as social networks and scale-free random networks. We explore the efficiency and traffic analysis resistance properties of mix networks based on unstructured topologies as opposed to theoretically optimal structured topologies, under high latency conditions. We consider a mix of directed and undirected network models, as well as one real world case study -- the LiveJournal friendship network topology. Our analysis indicates that mix-networks based on scale-free and small-world topologies have, firstly, mix-route lengths that are roughly comparable to those in expander graphs; second, that compromise of the most central nodes has little effect on anonymization properties, and third, batch sizes required for warding off intersection attacks need to be an order of magnitude higher in unstructured networks in comparison with expander graph topologies.
Peer to Peer Networks Management Survey
Mourad Amad,Ahmed Meddahi,Djamil Aissani
International Journal of Computer Science Issues , 2012,
Abstract: Peer-to-Peer systems are based on the concept of resources localization and mutualisation in dynamic context. In specific environment such as mobile networks, characterized by high variability and dynamicity of network conditions and performances, where nodes can join and leave the network dynamically, resources reliability and availability constitute a critical issue. The resource discovery problem arises in the context of peer to peer (P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network. Locating a resource or service efficiently is one of the most important issues related to peer to peer networks. The objective of a search mechanism is to successfully locate resources while incurring low overhead and low delay. This paper presents a survey on P2P networks management: classification, applications, platforms, simulators and security.
Peer to Peer Networks Management Survey  [PDF]
Mourad Amad,Ahmed Meddahi,Djamil A?ssani
Computer Science , 2012,
Abstract: Peer-to-Peer systems are based on the concept of resources localization and mutualisation in dynamic context. In specific environment such as mobile networks, characterized by high variability and dynamicity of network conditions and performances, where nodes can join and leave the network dynamically, resources reliability and availability constitute a critical issue. The resource discovery problem arises in the context of peer to peer (P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network. Locating a resource or service efficiently is one of the most important issues related to peer-to-peer networks. The objective of a search mechanism is to successfully locate resources while incurring low overhead and low delay. This paper presents a survey on P2P networks management: classification, applications, platforms, simulators and security.
Survey of Anonymity and Authentication in P2P Networks  [PDF]
Xiaoliang Wang,Lincong Yang,Xingming Sun,Jinsong Han
Information Technology Journal , 2010,
Abstract: Anonymity has received increasing attention in the literature due to the users` awareness of their privacy nowadays. While anonymity related issues have been extensively studied in peer-to-peer (P2P) systems, numerous concerns have been raised about the issue of providing authentic partners in P2P systems. In addition, the network authority requires authentication so that misbehaving entities in the network remain traceable. This study analyzes this problem and reviews related researches. Besides, we also advise some possible methods for this problem.
Improved Search Efficiency in Unstructured Peer to Peer Networks Using Search Result Path Caching
S. Anbu,K.P. Thooyamani
International Journal of Soft Computing , 2012,
Abstract: The huge popularity of recent Peer-to-Peer (P2P) file sharing systems has been mainly driven by the scalability of their architectures and the flexibility of their search facilities. Such systems are usually designed as Unstructured P2P networks. So, designing an efficient search algorithm is a key challenge in unstructured peer-to-peer networks due to the unstructured paradigm. In this study, we proposed a Search Result Path Caching algorithm (SRPC). The proposed scheme combines the Dynamic Search (DS) algorithm and result path caching for effective search. This proposed algorithm takes the advantages from dynamic search and path caching technique works with the queried results. After the successful discovery of results the queries are returned to originator, according to our proposed algorithm the originator will stores the results for future references. In future stored references are used to search the information without querying the overall network. We analyze the performance of our algorithm based on some performance metrics including the success rate, search time and search efficiency. The numerical results shows that the proposed SRPC algorithm performs about 5 times better than DS, 125 times better than flooding and 275 times better than Random Walk (RW) in power-law graphs.
MPO: An Efficient and Low-cost Peer-to-Peer Overlay for Autonomic Communications  [PDF]
Jiaqi Liu,Zhong Ren,Deng Li
Computer Science , 2012,
Abstract: The term Autonomic Communication (AC) refers to self-managing systems which are capable of supporting self-configuration, self-healing and self-optimization. However, information reflection and collection, lack of centralized control, non-cooperation and so on are just some of the challenges within AC systems. We have considered these problems in theory and practice and reached the following conclusion; in order to build an ideal system for autonomic communication, there are three key problems to be solved. Motivated by the need for AC, we have designed an efficient and low-cost Peer-to-Peer (P2P) overlay called Maya-Pyramid overlay (MPO) and combined merits of unstructured P2P with those of structured P2P overlays. Differing from the traditional hierarchical P2P (i.e. tree-like structure) overlay, (1) MPO is composed of levels and layers, which uses small world characteristic to improve efficiency, and the maintenance cost is decreased because update and backup only take place in two neighboring levels or layers instead of recursively perform in higher levels. (2) Unlike normal redundant mechanisms for solving the single fault problem: Tri-Information Center (Tri-IC) mechanism is presented in order to improve robustness by alleviating the load of cluster heads in a hierarchical P2P overlay. (3) A source ranking mechanism is proposed in order to discourage free riding and whitewashing and to encourage frequent information exchanges between peers. (4) Inspired by Pastry's ID structure for a structured DHT algorithm, a 3D unique ID structure is presented in the unstructured P2P overlay. This will guarantee anonymity in routing, and will be, not only more efficient because it applies the DHT-like routing algorithm in the unstructured P2P overlay, but also more adaptive to suit AC. Evaluation proved that MPO is robust, highly efficient and of a low-cost.
Avoiding Whitewashing in Unstructured Peer-to-Peer Resource Sharing Network  [PDF]
Ruchir Gupta,Yatindra Nath Singh
Computer Science , 2013,
Abstract: In peer-to-peer file sharing network, it is hard to distinguish between a legitimate newcomer and a whitewasher. This makes whitewashing a big problem in peer-to-peer networks. Although the problem of whitewashing can be solved using permanent identities, it may take away the right of anonymity for users. In this paper, we a have proposed a novel algorithm to avoid this problem when network uses free temporary identities. In this algorithm, the initial reputation is adjusted according to the level of whitewashing in the network.
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