Special issue on protocols and applications for wi

Authors: Kshirasagar Naik

Publish Date: 2012/01/14

Volume: 5, Issue: 2, Pages: 161-162

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Abstract

We are witnessing a paradigm shift in the design of internet scale distributed systems with peertopeer P2P communication playing an important role For large scale content distribution P2P communication is emerging as an alternative technology to the traditional clientserver systems File sharing and streaming audio/video are examples of popular P2P applications The key characteristics of some P2P systems are large scale extremely dynamic topology and decentralized control In addition ubiquity of wireless handheld devices namely smartphones and tablet computers has added a new dimension to the challenges facing the designers of P2P systems Due to advances in wireless communication technologies campus and enterprisewide availability of wireless networks are already a reality In some cases an entire metropolitan area is covered by a single wireless network As a result the demand to port network applications for mobile handheld devices is increasing In spite of many interesting technological developments wireless networks are still constrained by expensive bandwidth and variable channel qualities Similarly handheld devices have less resources namely processing memory storage and battery than laptop computers In addition security is an added concern in wireless P2P systems Therefore application and system designers are faced with new challenges in the domain of wireless P2P networks The objective of this special issue is to address some of those challengesIn the first article entitled ``Modeling Resource Constrained BitTorrent Proxies for Energy Efficient Mobile Content Sharing I Kelenyi proposes a twostep approach to download contents on handheld devices in an energy efficient manner In the first step data is moved from the server to an intermediate proxy in the second step the proxy sends data to smartphones in high speed bursts The twostep approach has been shown to save energy compared with regular direct data transfer from the server to smarphones Next they discuss how the proxy can be hosted on memory limited broadband routers found in homes Their results have been validated with both simulations and measurements of real life torrents on a prototype system running on home routers and smartohones running Symbian operating systemIn the second article entitled ``Towards an Effective Integration of Cellular Users to the Structured PeertoPeer Network M Zulhasnine C Huang and A Srinivasan proposed a scheme called cellular Chord CChord to integrate users of cellular networks into structured P2P networks in a topologyaware manner Their CChord scheme offers cellular users to make a choice while downloading data download either from the Internet peers at a faster rate or from other cellular users under the same base station Peer selection is an important step in their work They show how throughput can be significantly increased by carefully selecting peers among the potential sendersIn the third article entitled ``A Distributed Trust Management Model for Mobile P2P Networks X Wu proposes a distributed trust management model DTMM to construct short and robust trust chains in mobile P2P networks The paper focuses on prediction of future availability of wireless links and fast generation of valid trust evidences The paper makes a relationship between mobility patters and trust management in mobile P2P networks By means of simulations they show the scalability and robustness of their resultsWe would like to thank all anonymous reviewers who spent much of their precious time reviewing the papers Their timely reviews and insightful comments greatly helped the authors in revising their manuscripts and us in selecting the best papers for this special issue Taking this opportunity we thank all the authors who had submitted their manuscripts for possible publication in this special issue Special thanks go to the EditorinChief of the journal Professor Xuemin Sherman Shen for offering us the opportunity to edit this special issue

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