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1.
Durgesh Rani Kumari Hasan Guclu Murat Yuksel 《Peer-to-Peer Networking and Applications》2011,4(2):92-105
Several protocol efficiency metrics (e.g., scalability, search success rate, routing reachability and stability) depend on
the capability of preserving structure even over the churn caused by the ad-hoc nodes joining or leaving the network. Preserving
the structure becomes more prohibitive due to the distributed and potentially uncooperative nature of such networks, as in
the peer-to-peer (P2P) networks. Thus, most practical solutions involve unstructured approaches while attempting to maintain
the structure at various levels of protocol stack. The primary focus of this paper is to investigate construction and maintenance
of scale-free topologies in a distributed manner without requiring global topology information at the time when nodes join
or leave. We consider the uncooperative behavior of peers by limiting the number of neighbors to a pre-defined hard cutoff value (i.e., no peer is a major hub), and the ad-hoc behavior of peers by rewiring the neighbors of nodes leaving the network. We also investigate the effect of these hard cutoffs and
rewiring of ad-hoc nodes on the P2P search efficiency. 相似文献
2.
The decentralized peer-to-peer (P2P) technique has been widely used to implement scalable file sharing systems. It organizes nodes in a system into a structured or unstructured network. The advantages of the unstructured P2P systems are that they have lower maintenance complexity and can better adapt to node heterogeneity as well as network dynamics. However, the search process in unstructured systems is not as efficient as in structured P2P systems because the same search message may go through a node multiple times. To facilitate the complex search and improve the search efficiency, we propose a novel approach of assigning identifications to nodes in an unstructured system. Our method can prevent a node from receiving duplicate search messages and retain the low maintenance overhead for the system. The performance evaluations demonstrate that the proposed approach can improve the search efficiency of unstructured P2P systems while keeping the maintenance overhead at a comparable or even lower level, compared with the traditional unstructured systems. 相似文献
3.
《Journal of Network and Computer Applications》2010,33(2):115-127
Unstructured Peer-to-Peer (P2P) networks have become a very popular architecture for content distribution in large-scale and dynamic environments. Searching for content in unstructured P2P networks is a challenging task because the distribution of objects has no association with the organization of peers. Proposed methods in recent years either depend too much on objects replication rate or suffer from a sharp decline in performance when objects stored in peers change rapidly, although their performance is better than flooding or random walk algorithms to some extent. In this paper, we propose a novel query routing mechanism for improving query performance in unstructured P2P networks. We design a data structure called traceable gain matrix (TGM) that records every query's gain at each peer along the query hit path, and allows for optimizing query routing decision effectively. Experimental results show that our query routing mechanism achieves relatively high query hit rate with low bandwidth consumption in different types of network topologies under static and dynamic network conditions. 相似文献
4.
Nowadays, the peer-to-peer (P2P) system is one of the largest Internet bandwidth consumers. To relieve the burden on Internet backbone and improve the query and retrieve performance of P2P file sharing networks, efficient P2P caching algorithms are of great importance. In this paper, we propose a distributed topology-aware unstructured P2P file caching infrastructure and design novel placement and replacement algorithms to achieve optimal performance. In our system, for each file, an adequate number of copies are generated and disseminated at topologically distant locations. Unlike general believes, our caching decisions are in favor of less popular files. Combined with the underlying topology-aware infrastructure, our strategy retains excellent performance for popular objects while greatly improves the caching performance for less popular files. Overall, our solution can reduce P2P traffic on Internet backbone, and relieve the over-caching problem that has not been properly addressed in unstructured P2P networks. We carry out simulation experiments to compare our approaches with several traditional caching strategies. The results show that our algorithms can achieve better query hit rates, smaller query delay, higher cache hit rates, and lower communication overhead. 相似文献
5.
A great number of recent works deal with improving search in peer-to-peer systems, specifically by clustering peers into semantic groups. When the process of clustering is predetermined and static, it suffers from lack of adaptation to highly dynamic peer-to-peer environments. We model the problem as a non-superadditive coalition game with non-transferable utility characteristic function, and propose a distributed dynamic coalition formation algorithm through myopic best-reply with experiment rule to solve the coalition formation problem. Coalitions are formed by peers with similar interests considering geographical proximity. The overlay network is dynamically reconfigured over time based on the changes in the interests or locations of the individual peers. The convergence of the proposed algorithm using “core solution” concept is studied. The simulation results show that the proposed algorithm can efficiently reduce the search time, although the overhead of the overlay adaptation is slightly higher. 相似文献
6.
Guoqiang Gao Ruixuan Li Kunmei Wen Xiwu Gu 《Journal of Network and Computer Applications》2012,35(1):85-96
Unstructured peer-to-peer (P2P) networks have become a very popular architecture for content distribution in large-scale and dynamic environments. The search efficiency problem in unstructured P2P networks has not been adequately addressed so far, especially concerning search for rare objects. In this paper, we propose a proactive replication strategy to improve search efficiency for rare objects. It uses an object-probing technique for peers to decide whether or not to establish replications for their objects when they join the network. This strategy can effectively increase the popularity of rare objects in order to enhance search efficiency. We also present a rare object search algorithm to reduce the overhead caused by the replication strategy. When a peer forwards a search request, the forward probability is calculated according to its neighbors' degrees and the number of neighbors' objects. Therefore, the search request is forwarded to the peers more likely containing target objects. Simulations show that our proactive replication strategy greatly improves search efficiency for rare objects with moderate communication overhead. The rare object search algorithm not only improves search efficiency for rare objects, but also achieves load balance in search. 相似文献
7.
针对分布式点对点(P2P)网络中的信任管理问题,提出了一种多维度的信任管理机制。它运用直接信任评估和间接信任评估方法,依据各用户的行为来判定系统中用户的可信任程度,从而避免因为恶意用户的恶意反馈对网络造成的负面影响。在Bad Mouthing和on-off攻击场景下与EigenTrust方法进行对比,所提出的方法取得了较好的有效传输率(SRT),表明该机制能够有效地抑制恶意用户的行为。 相似文献
8.
Mursalin Akon Xuemin Shen Sagar Naik Ajit Singh Qian Zhang 《Peer-to-Peer Networking and Applications》2008,1(1):75-90
In this paper, we propose an unstructured platform, namely I
nexpensive
P
eer-to-
P
eer
S
ubsystem (IPPS), for wireless mobile peer-to-peer networks. The platform addresses the constraints of expensive bandwidth of wireless medium,
and limited memory and computing power of mobile devices. It uses a computationally-, memory requirement- and communication-
wise inexpensive gossip protocol as the main maintenance operation, and exploits location information of the wireless nodes
to minimize the number of link-level messages for communication between peers. As a result, the platform is not only lightweight
by itself, but also provides a low cost framework for different peer-to-peer applications. In addition, further enhancements
are introduced to enrich the platform with robustness and tolerance to failures without incurring any additional computational
and memory complexity, and communication between peers. In specific, we propose schemes for a peer (1) to chose a partner
for a gossip iteration, (2) to maintain the neighbors, and (3) to leave the peer-to-peer network. Simulation results are given
to demonstrate the performance of the platform.
Mursalin Akon received his B.Sc.Engg. degree in 2001 from the Bangladesh University of Engineering and Technology (BUET), Bangladesh, and his M.Comp.Sc. degree in 2004 from the Concordia University, Canada. He is currently working towards his Ph.D. degree at the University of Waterloo, Canada. His current research interests include peer-to-peer computing and applications, network computing, and parallel and distributed computing. Xuemin Shen received the B.Sc. (1982) degree from Dalian Maritime University (China) and the M.Sc. (1987) and Ph.D. degrees (1990) from Rutgers University, New Jersey (USA), all in electrical engineering. He is a Professor and the Associate Chair for Graduate Studies, Department of Electrical and Computer Engineering, University of Waterloo, Canada. His research focuses on mobility and resource management in wireless/wired networks, wireless security, ad hoc and sensor networks, and peer-to-peer networking and applications. He is a co-author of three books, and has published more than 300 papers and book chapters in different areas of communications and networks, control and filtering. Dr. Shen serves as the Technical Program Committee Chair for IEEE Globecom’07, General Co-Chair for Chinacom’07 and QShine’06, the Founding Chair for IEEE Communications Society Technical Committee on P2P Communications and Networking. He also serves as the Editor-in-Chief for Peer-to-Peer Networking and Application; founding Area Editor for IEEE Transactions on Wireless Communications; Associate Editor for IEEE Transactions on Vehicular Technology; KICS/IEEE Journal of Communications and Networks, Computer Networks; ACM/Wireless Networks; and Wireless Communications and Mobile Computing (Wiley), etc. He has also served as Guest Editor for IEEE JSAC, IEEE Wireless Communications, and IEEE Communications Magazine. Dr. Shen received the Excellent Graduate Supervision Award in 2006, and the Outstanding Performance Award in 2004 from the University of Waterloo, the Premier’s Research Excellence Award (PREA) in 2003 from the Province of Ontario, Canada, and the Distinguished Performance Award in 2002 from the Faculty of Engineering, University of Waterloo. Dr. Shen is a registered Professional Engineer of Ontario, Canada. Sagar Naik received his BS, M. Tech., M. Math., and Ph.D. degrees from Sambalpur University (India), Indian Institute of Technology, University of Waterloo, and Concordia University, respectively. From June 1993 to July 1999 he was on the Faculty of Computer Science and Engineering at the University of Aizu, Japan, as an Assistant and Associate Professor. At present he is an Associate Professor in the Department of Electrical and Computer Engineering, University of Waterloo. His research interests include mobile communication and computing, distributed and network computing, multimedia synchronization, power-aware computing and communication. Ajit Singh received the B.Sc. degree in electronics and communication engineering from the Bihar Institute of Technology (BIT), Sindri, India, in 1979 and the M.Sc. and Ph.D. degrees from the University of Alberta, Edmonton, AB, Canada, in 1986 and 1991, respectively, both in computing science. From 1980 to 1983, he worked at the R&D Department of Operations Research Group (the representative company for Sperry Univac Computers in India). From 1990 to 1992, he was involved with the design of telecommunication systems at Bell-Northern Research, Ottawa, ON, Canada. He is currently an Associate Professor at Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada. His research interests include network computing, software engineering, database systems, and artificial intelligence. Qian Zhang received the B.S., M.S., and Ph.D. degrees from Wuhan University, Wuhan, China, in 1994, 1996, and 1999, respectively, all in computer science. In July 1999, she was with Microsoft Research, Asia, Beijing, China, where she was the Research Manager of the Wireless and Networking Group. In September 2005, she joined Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, as an Associate Professor. She has published about 150 refereed papers in international leading journals and key conferences in the areas of wireless/Internet multimedia networking, wireless communications and networking, and overlay networking. She is the inventor of about 30 pending patents. Her current research interests are in the areas of wireless communications, IP networking, multimedia, P2P overlay, and wireless security. She also participated in many activities in the IETF ROHC (Robust Header Compression) WG group for TCP/IP header compression. Dr. Zhang is an Associate Editor for the IEEE Transactions on Wireless Communications, IEEE Transactions on Multimedia, IEEE Transactions on Vehicular Technologies, and Computer Communications. She also served as the Guest Editor for a Special Issue on Wireless Video in the IEEE Wireless Communication Magazine and is serving as a Guest Editor for a Special Issue on Cross Layer Optimized Wireless Multimedia Communication in the IEEE Journal on Selected Areas in Communications. She received the TR 100 (MIT Technology Review) World’s Top Young Innovator Award. She also received the Best Asia Pacific (AP) Young Researcher Award from the IEEE Communication Society in 2004. She received the Best Paper Award from the Multimedia Technical Committee (MMTC) of IEEE Communication Society. She is the Chair of QoSIG of the Multimedia Communication Technical Committee of the IEEE Communications Society. She is also a member of the Visual Signal Processing and Communication Technical Committee and the Multimedia System and Application Technical Committee of the IEEE Circuits and Systems Society. 相似文献
Qian ZhangEmail: |
Mursalin Akon received his B.Sc.Engg. degree in 2001 from the Bangladesh University of Engineering and Technology (BUET), Bangladesh, and his M.Comp.Sc. degree in 2004 from the Concordia University, Canada. He is currently working towards his Ph.D. degree at the University of Waterloo, Canada. His current research interests include peer-to-peer computing and applications, network computing, and parallel and distributed computing. Xuemin Shen received the B.Sc. (1982) degree from Dalian Maritime University (China) and the M.Sc. (1987) and Ph.D. degrees (1990) from Rutgers University, New Jersey (USA), all in electrical engineering. He is a Professor and the Associate Chair for Graduate Studies, Department of Electrical and Computer Engineering, University of Waterloo, Canada. His research focuses on mobility and resource management in wireless/wired networks, wireless security, ad hoc and sensor networks, and peer-to-peer networking and applications. He is a co-author of three books, and has published more than 300 papers and book chapters in different areas of communications and networks, control and filtering. Dr. Shen serves as the Technical Program Committee Chair for IEEE Globecom’07, General Co-Chair for Chinacom’07 and QShine’06, the Founding Chair for IEEE Communications Society Technical Committee on P2P Communications and Networking. He also serves as the Editor-in-Chief for Peer-to-Peer Networking and Application; founding Area Editor for IEEE Transactions on Wireless Communications; Associate Editor for IEEE Transactions on Vehicular Technology; KICS/IEEE Journal of Communications and Networks, Computer Networks; ACM/Wireless Networks; and Wireless Communications and Mobile Computing (Wiley), etc. He has also served as Guest Editor for IEEE JSAC, IEEE Wireless Communications, and IEEE Communications Magazine. Dr. Shen received the Excellent Graduate Supervision Award in 2006, and the Outstanding Performance Award in 2004 from the University of Waterloo, the Premier’s Research Excellence Award (PREA) in 2003 from the Province of Ontario, Canada, and the Distinguished Performance Award in 2002 from the Faculty of Engineering, University of Waterloo. Dr. Shen is a registered Professional Engineer of Ontario, Canada. Sagar Naik received his BS, M. Tech., M. Math., and Ph.D. degrees from Sambalpur University (India), Indian Institute of Technology, University of Waterloo, and Concordia University, respectively. From June 1993 to July 1999 he was on the Faculty of Computer Science and Engineering at the University of Aizu, Japan, as an Assistant and Associate Professor. At present he is an Associate Professor in the Department of Electrical and Computer Engineering, University of Waterloo. His research interests include mobile communication and computing, distributed and network computing, multimedia synchronization, power-aware computing and communication. Ajit Singh received the B.Sc. degree in electronics and communication engineering from the Bihar Institute of Technology (BIT), Sindri, India, in 1979 and the M.Sc. and Ph.D. degrees from the University of Alberta, Edmonton, AB, Canada, in 1986 and 1991, respectively, both in computing science. From 1980 to 1983, he worked at the R&D Department of Operations Research Group (the representative company for Sperry Univac Computers in India). From 1990 to 1992, he was involved with the design of telecommunication systems at Bell-Northern Research, Ottawa, ON, Canada. He is currently an Associate Professor at Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada. His research interests include network computing, software engineering, database systems, and artificial intelligence. Qian Zhang received the B.S., M.S., and Ph.D. degrees from Wuhan University, Wuhan, China, in 1994, 1996, and 1999, respectively, all in computer science. In July 1999, she was with Microsoft Research, Asia, Beijing, China, where she was the Research Manager of the Wireless and Networking Group. In September 2005, she joined Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, as an Associate Professor. She has published about 150 refereed papers in international leading journals and key conferences in the areas of wireless/Internet multimedia networking, wireless communications and networking, and overlay networking. She is the inventor of about 30 pending patents. Her current research interests are in the areas of wireless communications, IP networking, multimedia, P2P overlay, and wireless security. She also participated in many activities in the IETF ROHC (Robust Header Compression) WG group for TCP/IP header compression. Dr. Zhang is an Associate Editor for the IEEE Transactions on Wireless Communications, IEEE Transactions on Multimedia, IEEE Transactions on Vehicular Technologies, and Computer Communications. She also served as the Guest Editor for a Special Issue on Wireless Video in the IEEE Wireless Communication Magazine and is serving as a Guest Editor for a Special Issue on Cross Layer Optimized Wireless Multimedia Communication in the IEEE Journal on Selected Areas in Communications. She received the TR 100 (MIT Technology Review) World’s Top Young Innovator Award. She also received the Best Asia Pacific (AP) Young Researcher Award from the IEEE Communication Society in 2004. She received the Best Paper Award from the Multimedia Technical Committee (MMTC) of IEEE Communication Society. She is the Chair of QoSIG of the Multimedia Communication Technical Committee of the IEEE Communications Society. She is also a member of the Visual Signal Processing and Communication Technical Committee and the Multimedia System and Application Technical Committee of the IEEE Circuits and Systems Society. 相似文献
9.
韦文代 《计算机工程与设计》2011,32(1):92-95
描述了一个基于非结构化对等网络、可以共享网络上空闲资源的JVMs虚拟机的桌面网格平台UDDG(unstructureddecentralized desktop grid)。提出了对等实体的最小活跃邻居节点数、更新时间域值等概念,每个对等实体维护了一个最小活跃邻居数的列表,结合非结构化对等网络的网络跳数的机制,通过广播查找消息来寻找资源的虚拟机。通过构建评测环境,运行并行案例程序计算结果表明,UDDG提供了一种构建高性能的桌面网格平台的新思路。 相似文献
10.
With emerging Internet-scale open content and resource sharing, social networks, and complex cyber-physical systems, trust issues become prominent. Conventional trust mechanisms are inadequate at addressing trust issues in decentralized open environments. In this paper, we propose a trust vector based trust management scheme called VectorTrust for aggregation of distributed trust scores. Leveraging a Bellman–Ford based algorithm for fast and lightweight trust score aggregation, VectorTrust features localized and distributed concurrent communication. Built on a trust overlay network in a peer-to-peer network, a VectorTrust-enabled system is decentralized by nature and does not rely on any centralized server or centralized trust aggregation. We design, implement, and analyze trust rating, trust aggregation, and trust management strategies. To evaluate the performance, we design and implement a VectorTrust simulator (VTSim) in an unstructured P2P network. The analysis and simulation results demonstrate the efficiency, accuracy, scalability, and robustness of VectorTrust scheme. On average, VectorTrust converges faster and involves less complexity than most existing trust schemes. VectorTrust remains robust and tolerant to malicious peers and malicious behaviors. With dynamic growth of P2P network scales and topology complexities, VectorTrust scales well with reasonable overheads (about O(lg?N) communication overheads) and fast convergence speed (about O(log? D N) iterations). 相似文献
11.
Decentralized Peer-to-Peer (P2P) networks offer not only opportunities but also threats. Due to the autonomy, self-interest
and heterogeneousness of peers, the interaction outcomes are uncertain. One way to minimize the threats in such an open environment
is exploiting the reputation method to evaluate the trustworthiness and predict the future behaviors of peers. While most
of the existing reputation-based trust models focus on preventing network from the malicious peers, peers’ capabilities to
fulfill the tasks are mostly ignored. In this paper, we present a novel trust model MHFTrust which quantifies and compares
the trustworthiness of peers based on hierarchical fuzzy system. Six capability factors are identified to describe the peers’
trust on the capability, and one security factor, named “Malicious behavior” is used to evaluate the peers’ trust on security.
Our trust model consisted of local-trust computation based on fuzzy techniques and global reputation aggregation, which integrates
feedback from other peers to produce a global reputation for each peer. Credibility and weight of feedback are introduced
to facilitate the computation of global reputation. It is shown in simulation that our trust model greatly improves the efficiency
of P2P system, while the number of inauthentic files on the network is significantly decreased. 相似文献
12.
《Computer Networks》2007,51(10):2818-2832
Efficient search algorithms are crucial to the success of unstructured and hybrid peer-to-peer networks. Performance requirements on search algorithms include low search traffic, low search latency, and determinism in returning the searched items. However, existing search algorithms fail to meet these goals. We propose, analyze, and evaluate two novel flooding search algorithms. The first algorithm conducts on-the-fly estimation of the popularity of the searched item, and uses such knowledge to guide a peer’s search process. It requires the minimum search cost and very low latency, and albeit its non-determinism, often returns the desired number of results. The second algorithm, Hurricane flooding, exponentially expands the search horizon of the source of a search in a spiral pattern. Hurricane flooding is deterministic, requires search cost arbitrarily close to a lower bound, and returns the results in logarithmic time. We analyze and optimize our proposed algorithms, and evaluate them using various network models, including a real Gnutella network topology. 相似文献
13.
Peer-to-Peer (P2P) file sharing is the hottest, fastest growing application on the Internet. When designing Gnutella-like
applications, the most important consideration is the scalability problem, because P2P systems typically support millions
of users online concurrently. Gnutella suffers from poor scaling due to its flooding-based search, resulting in excessive
amounts of repeated query messages. Therefore, a good search protocol plays an important role in a system’s scalability. However,
congestion, due to large query loads from users, definitely impacts on the performance of search protocols, and this consideration
has received little attention from the research community. In this paper, we propose a congestion-aware search protocol for
unstructured P2P networks. Our protocol consists of three parts—Congestion-Aware Forwarding, Random Early Stop and Emergency
Signaling. The aim of our protocol is to integrate congestion control and object discovery functionality so that the search
protocol can achieve good performance under congested networks and flash crowds. We perform extensive simulations to study
our proposed protocol. The results show that our protocol can significantly reduce the hit delay while maintaining the high
hit rate and also the congestion problems such as query loss and the peer overloading problem can be effectively alleviated. 相似文献
14.
Peer-to-Peer (P2P) computing has recently attracted a great deal of research attention. In a P2P system, a large number of nodes can potentially be pooled together to share their resources, information, and services. However, existing unstructured P2P systems lack support for content-based search over data objects which are generally represented by high-dimensional feature vectors. In this paper, we propose an efficient and effective indexing mechanism to facilitate high-dimensional similarity query in unstructured P2P systems, named Linking Identical Neighborly Partitions (LINP), which combines both space partitioning technique and routing index technique. With the aid of LINP, each peer can not only process similarity query efficiently over its local data, but also can route the query to the promising peers which may contain the desired data. In the proposed scheme, each peer summarizes its local data using the space partitioning technique, and exchanges the summarized index with its neighboring peers to construct routing indices. Furthermore, to improve the system performance with peer updates, we propose an extension of the LINP, named LINP+, where each peer can reconfigure its neighboring peers to keep relevant peers nearby. The performance of our proposed scheme is evaluated over both synthetic and real-life high-dimensional datasets, and experimental results show the superiority of our proposed scheme. 相似文献
15.
Free-rider problem greatly influences the performance of unstructured networks (like ad hoc or peer-to-peer networks). To solve such problem, we focus on trust management framework, which is intended to stimulate nodes to cooperate with each other and prevent free-riders. Currently, the existing trust management framework can be classified into trust establishment framework and reputation-based framework. None of them, however, was explicitly designed with the considerations on neutrality, which is indispensable issue when devising a network system. Therefore, we attempt to march towards the design of neutral trust management framework in this paper. We firstly investigate the relation between neutrality and trust definition, and identify the requirements for design of neutral trust management framework. Then, we focus on trust management of one kind of typical unstructured networks, mobile ad hoc network (MANET). We design a neutral trust management framework of MANET to meet the clarified design requirements. Further, we perform analysis on our proposed framework, which shows our proposal can achieve neutrality under the location-dependent attack of free-rider in MANET. 相似文献
16.
《Simulation Modelling Practice and Theory》2007,15(4):449-464
A multimedia contents are distributed to peer computers (peers) and a contents peer which holds contents can provide other peers with the contents in peer-to-peer (P2P) overlay networks. Here, contents peers are mainly realized in less-reliable and low-performance personal computers. Multimedia streaming is more significant than downloading ways in multimedia applications from security and economical reasons. We discuss distributed multi-source streaming models to support peers with reliable and scalable multimedia streaming service. Here, a collection of multiple contents peers in parallel transmit packets of a multimedia content to a leaf peer to realize the reliability and scalability. Each of the contents peers send different packets from the other contents peers at slower rate. Even if not only some number of peers stop by fault and are degraded in performance but also some number of packets are lost and delayed in networks, a leaf peer has to receive every data of a content at the required rate. We discuss how to replicate data of a multimedia content by creating a parity packet for some number of packets and to allocate packets to each contents peer so that a leaf peer can deliver a packet without waiting for preceding packets from other contents peers in presence of the faults. Next, multiple contents peers are required to be synchronized to send packets to a leaf-peer so that the leaf-peer can receive every data of a content at the required rate. We discuss a pair of gossip-based flooding-based protocols, directed acyclic graph (DAG)-based coordination protocol (DCoP) and tree-based (TCoP) coordination protocol to synchronize multiple contents peers to send in parallel send to a leaf peer. First, some number of contents peers are selected and start transmitting packets to a leaf peer. Then, each of the selected peers selects some number of peers. Here, a peer can be selected by multiple peers in DCoP but by at most one peer in TCoP. Finally, every contents peer transmits packets to the leaf peer at the allocated rate. We evaluate the coordination protocols DCoP and TCoP in terms of how long it takes and how many messages are transmitted to synchronize multiple contents peers. 相似文献
17.
Contention-based performance evaluation of multidimensional range search in peer-to-peer networks 总被引:1,自引:0,他引:1
Performance evaluation of peer-to-peer search techniques has hitherto been based on simple performance metrics, such as message hop counts and total network traffic, mostly disregarding the inherently concurrent nature of peer-to-peer networks, where contention may arise. This paper is concerned with quantifying the effects of contention in P2P networks, focusing on networks for multidimensional range search. We evaluate peer-to-peer networks derived from recently proposed works, introducing two novel metrics related to concurrency and contention, namely responsiveness and throughput. Our results highlight the impact of contention on these networks, and demonstrate that some studied networks do not scale in the presence of contention. Also, our results indicate that certain P2P network properties believed to be desirable (e.g. even data distribution or uniform peer access) may not be as critical as previously believed. 相似文献
18.
《Journal of Parallel and Distributed Computing》2005,65(2):142-153
The “small-world” graph structure is pervasive and is observed to arise “without-design” or “naturally” in many practical systems such as the World Wide Web. In contrast to natural systems, overlay networks provide an opportunity to design structure. We seek the advantages of designing overlay topologies with small-world properties to support file sharing in peer-to-peer networks. We focus on two metrics of performance: (a) search protocol performance, a local gain perceived directly by peer-to-peer network users and (b) network utilization, a global property that is of interest to network service providers. We propose a class of overlay topologies and show, by simulation, that a particular topology instance of this class where every node has many close neighbors and few random neighbors (i.e., a small-world graph) exhibits very good properties. In this overlay topology, the chances of locating files are high, and the nodes where these files are found are, on average, close to the query source. This improvement in search protocol performance is achieved while decreasing the traffic load on the links in the underlying network. We propose a simple greedy algorithm to construct such overlay topologies where each node operates independently and in a decentralized manner to select its neighbors. 相似文献
19.
20.
Location awareness in unstructured peer-to-peer systems 总被引:7,自引:0,他引:7
Yunhao Liu Li Xiao Xiaomei Liu Ni L.M. Xiaodong Zhang 《Parallel and Distributed Systems, IEEE Transactions on》2005,16(2):163-174
Peer-to-peer (P2P) computing has emerged as a popular model aiming at further utilizing Internet information and resources. However, the mechanism of peers randomly choosing logical neighbors without any knowledge about underlying physical topology can cause a serious topology mismatch between the P2P overlay network and the physical underlying network. The topology mismatch problem brings great stress in the Internet infrastructure. It greatly limits the performance gain from various search or routing techniques. Meanwhile, due to the inefficient overlay topology, the flooding-based search mechanisms cause a large volume of unnecessary traffic. Aiming at alleviating the mismatching problem and reducing the unnecessary traffic, we propose a location-aware topology matching (LTM) technique. LTM builds an efficient overlay by disconnecting slow connections and choosing physically closer nodes as logical neighbors while still retaining the search scope and reducing response time for queries. LTM is scalable and completely distributed in the sense that it does not require any global knowledge of the whole overlay network. The effectiveness of LTM is demonstrated through simulation studies. 相似文献