The improvement of caching strategies about unstructured P2P system

In recent years, peer-to-peer (P2P) systems have become a promising paradigm to provide efficient storage service in distributed environments. Although its effectiveness has been proven in many areas, the data consistency problem in P2P systems are still an opening issue. This article proposes a novel data consistence model, virtual peers-based data consistency (VPDC), which introduces a set of virtual peers to provide guaranteed data consistency in decentralized and unstructured P2P systems. The VPDC model can be easily implemented in any P2P system without introducing any interference to data retrieval. Theoretical analysis on VPDC is presented to analyze its effectiveness and efficiency, and massive experiments are conducted to evaluate the performance of a VPDC model in a real-world P2P system. The results indicate that it can significantly improve the data consistence of P2P systems and outperform many similar approaches in various experimental settings.

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An Efficient Searching Scheme in Unstructured P2P Networks

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.439-440.865 ◽

2010 ◽

Vol 439-440 ◽

pp. 865-869 ◽

Cited By ~ 1

Author(s):

Ming Zhang ◽

Jin Qiu Yang

Keyword(s):

Routing Protocol ◽

Adaptive Routing ◽

P2p Networks ◽

Community Network ◽

Simple Scheme ◽

P2p Systems ◽

Simulation Results ◽

Unstructured P2p ◽

P2p System ◽

Present Simulation

Unstructured peer-to-peer (P2P) systems，due to their excellent support for content lookup and sharing，are creating a large proportion of network traffic in today’s Internet. A P2P system typically involves thousands or millions of live peers in the network. In this paper, we propose and evaluate an efficient searching scheme in unstructured P2P networks. This scheme proposes a local adaptive routing protocol. This routing protocol adopts a simple scheme which driven by query interest among peers. We analyze this scheme’s performance and present simulation results. Our simulation results demonstrated the benefits of the proposed system and show that the approach is able to dynamically group nodes in clusters containing peers with shared interests, at the same time, and organized into a community network.

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Proxy Caching Strategies for Internet Media Streaming

Encyclopedia of Information Science and Technology, Second Edition ◽

10.4018/978-1-60566-026-4.ch505 ◽

2011 ◽

pp. 3166-3170

Author(s):

Manuela Pereira ◽

Mário M. Freire

Keyword(s):

Media Streaming ◽

The Internet ◽

Proxy Caching ◽

Client Server ◽

P2p Systems ◽

Web Objects ◽

Processing Power ◽

Media Objects ◽

P2p System ◽

Caching Strategies

information while being downloaded by clients. With the explosive growth of the Web and the mature of digital video technology, media streaming has received a great deal of interest as a promising solution for multimedia delivery services. This approach allows that media objects can be accessed in a similar way to conventional text and images using a download-and-play mode. However, unlike static text-based content, proxy caching has difficulty in delivering streaming media content because media objects are usually very large and its transmission consumes a great amount of network resources, prolongs startup latency, and threatens the playback continuity. The size of a conventional Web object is typically on the order of 1–100 kbytes and, therefore, a decision regarding either caching or not an object in its totality is an easy task (Liu & Xu, 2004). However, the size of media objects is very large, reaching a size on the order of several hundreds of Mbytes or even Gbytes. Therefore, caching a whole media object at a Web proxy optimized for delivering conventional small-size Web objects is not feasible, since large streams would quickly exhaust the capacity of the proxy cache. Besides, the streaming of media objects requires a significant amount of resources such as disk space and network bandwidth, which need to be maintained during a long period of time. Moreover, the long playback duration of a streaming may allow several client-server interactions. Therefore, access rates might be different for different parts of a stream, which makes cache management potentially more complex, as pointed out by Liu and Xu (2004). On the other hand, a download-beforeplaying solution provides continuous playback, but it also introduces a large startup delay. An effective solution to reduce client-perceived latencies and network congestion is to cache data at proxies widely deployed across the Internet. This solution, besides inexpensive, also leads to an improvement of both availability of objects and packet losses since redundant network transmission decreases while transmission efficiency increases. However, proxies are generally optimized for delivering conventional small-size Web objects, which may not satisfy the requirements of streaming applications. Due to these particular features of media objects, novel caching strategies have been proposed. With the evolution of the Internet as the dominant architecture for applications, contents, and services, these are gradually migrating from the client-server paradigm to the edge services paradigm and to the peer-to-peer (P2P) computing paradigm. Recently, P2P system has received a great amount of interest as a promising scalable and costeffective solution for next-generation multimedia content distribution. This kind of systems have advantages regarding systems based on the client-server paradigm, namely improved scalability and reliability, cheaper infrastructures due to direct communication among peers, and easiness of resource aggregation in order to provide, for instance, massive processing power (Ye, Makedon, & Ford, 2004). However, P2P systems also have some drawbacks, namely the considerably more complex searching and node organization and security issues (Aberer, Punceva, Hauswirth, & Schmidt., 2002). Therefore, this article limits the discussion to low-cost proxy caching strategies for media streaming over Internet.

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