Transcript P2P的問題

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Authors: Altmann, J. ; Bedane, Z.B.
INFOCOM Workshops 2009, IEEE
DOI: 10.1109/INFCOMW.2009.5072101
Publication Year: 2009 , Page(s): 1 - 6
Cited by: Papers (5)
報告者：
Ma1g0222 童耀民 2015/03/09
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Introduction.(介紹)
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P2P Issues. (P2P的問題)
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Topology Formation Algorithm (拓樸組成演算法)
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Simulation.(模擬)
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Conclusion.(結論)
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 Peer-to-Peer (P2P) systems are among the newly emerging Internet resource sharing
mechanisms for sharing content files, processing cycles, disk storage, and bandwidth.
(同儕式網路系統，用於檔案內容共享、處理週期、磁碟儲存跟頻寬的新崛起的網路資源共享機制)
 The core objective of P2P systems is to create an efficient system through which
users share Internet resources among a group of peers.
(同儕式網路系統的核心目標是建立一個有效的系統，通過它在一群Peer，使用者共享網路資源)
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 Although P2P systems have huge potential, there are technical and non-technical
challenges.
(雖然同儕式網路系統具有強大的潛力，有技術和非技術的挑戰)
 Free-riding, security breaches, existence of firewalls/NATs, and non-ethical behavior
of users are the main prevailing challenges.
(搭便車、安全漏洞、存在防火牆 / NATs 及 使用者非道德的行為的主要的挑戰)
 This paper proposes a solution to two of those issues (free-riding and existence of
firewalls/NATs), using social network information [ 18 ].
(本文提出了一種解決方案，其中的兩項問題(搭便車跟存在防火牆/NATs)，使用社交網路訊息)
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 It will use this information for formulating a topology formation algorithm that will
help to mitigate or even avoid these issues.
(將利用這些訊息制定拓樸組成演算法，這將有助於減輕甚至避免這些問題)
 The underlying research questions that are addressed within this paper are:
(這篇文章中涉及的基本研究問題是:
 (i) How do we integrate social network information into hybrid P2P networks like Gnutella to
discourage free riders?
(我們如何整合社交網路訊息用來結合同儕網路，像是Gnutella的勸阻搭便車
 (ii) How can we improve the use of super nodes as a relay machine to overcome the firewall/NAT
problem?
(我們怎樣才能提高利用超級節節點(super nodes,SN)作為中繼機器，克服防火牆/NAT問題?
 (iii) To what extent can the new system (the social-network-based P2P network topology formation
algorithm) reduce inefficient performance without affecting the performance of the super node?
(在何種程度上可以在新系統減少低效率的性能，而不會影響超級節點的性能?
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 The algorithm extends the Gnutella P2P file sharing technology, which uses super
nodes for searching and for relaying shared files between network leafs that are
located behind Firewalls/NATs.
(該演算法擴展Gnutella的同儕檔案共享技術，利用超級節點，用於搜尋和中繼子節點網路之間的檔案共享)
 They simulate the proposed topology formation algorithm, considering the real
characteristics of the Gnutella P2P network and realistic network topologies.
(他們模擬了 拓樸組成演算法，考慮到Gnutella的同儕網路和現實的網路拓樸結構的真實特性)
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 A. Free-Riding (搭便車)
 Free-riding is the main issue for the further development and application of P2P
systems.
(搭便車是P2P系統更進一步發展和應用的主要問題)
 For instance, a study of a Gnutella network showed that 70% of the peers do not
share any files at all.
(70% Peer沒有共享任何檔案)
 Furthermore, 63% of the peers, who share some files, do not get any queries for
these files [1].
(63% Peer 分享一些沒有相關的檔案)
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 The studies indicate that free-riding exist in two forms.
(搭便車以兩種形式存在)
 Free riders, who do not share files at all, and
(不共享檔案)
 Free riders, who share files with irrelevant content.
(共享無相關的檔案)
 Consequently, relevant shared files are concentrated among a limited number of
peers, causing network congestion.
(因此，有相關的共享檔案被集中在少數的Peer，導致網路雍塞)
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 B. Firewalls/NATs(防火牆/NAT)
 Firewalls and Network Address Translators (NATs) create another issue for P2P
networks.
(防火牆及網路位址轉換(NAT)創建是另一個P2P網路的問題)
 In P2P networks like Gnutella, file sharing is not possible if both nodes are behind
NATs.
(P2P網路像Gnutella，兩個節點再防火牆後面NAT，檔案共享是不可能的)
 First, peers cannot directly consume resources from other peers, and, second, they
cannot provide their resources to other peers.
(首先，Peer無法從其他Peer直接消耗資源。第二，他們不能提供他們的資源給其他Peer)
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 Generally, the NAT problem forces P2P systems to depart to some extent from its
basic concept and adapt a central management concept.
(一般來說，NAT問題forces P2P系統，從它某種程度上的基本概念及集中管理)
 A weak form of this is the involvement of a third party (another peer) that is not
behind a firewall.
(這種第三方(another peer)不能是參與在防火牆後面的弱勢形式)
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 For instance, although Skype attempts to solve the NAT problem by using super
nodes as a relay machine, users behind NATs experience low performance when
transferring files.
(例如，儘管Skype嘗試使用超級節點作為中繼機器解決了NAT問題，NAT後面使用者傳輸檔案時遇到低性能)
 This is caused by the fact that Skype limits the file transmission speed to 5 kbps.
(這是由Skype的檔案傳輸速度限制在5 kbps的事實引起的)
 The low transmission speed avoids overloading super nodes with forwarding packets
and, therefore, avoids performance degradation of super nodes [ 2 ].
(低傳輸速率可以避免過載的超級節點與轉發分組，病因物避免了超級節點的性能下降)
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 A. Social Network Information in P2P Systems
 In this survey, the researchers considered
two scenarios:
(調查中，研究人員考慮兩種方案:
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 The central research question of this survey has been “What makes a super node
share its resources for the benefits of its contacts?”
(本次調查的核心問題一直是”是什麼讓一個超級節點共享資源，其中好處?
 According to the survey results, on average, 31.30% of the contact lists contains
family members, 36.28% close friends, 3.74% loose contacts, 22.56% work
acquaintances, 2.16% friend of a friend, 3.68% people who sent invitations to make
friends, and 0.28% belonged to other groups.
(根據調查結果，平均來說，再聯絡人列表的31.30%包括家庭成員、36.28%摯友、3.74%接觸不良?、22.56%
工作夥伴、2.16%朋友的朋友、3.68%的人陌生交友和0.28%屬於其他群)
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 B. SocialGnutella Algorithm
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Components of SocialGnutella (組成)
 The three components of the new topology formation algorithm are super nodes,
ordinary nodes, and the contact list of the nodes:
(新拓樸組成演算法的三個組成元件是超級節點(SN)、普通節點(N)、聯絡人列表)
 Super Nodes (SN):當作中繼機器和路由器。根據表現能力及防火牆/NAT選擇 (SN不受防火牆/NAT限制)
 Ordinary Nodes (N):不具有超級節點狀態。(可以是或不是在防火牆/NAT後面)
 Contact List:每個節點都有一個聯絡人列表，其中包含有關他們的聯絡人訊息。社交關係分成 強/弱/遊客
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2)
Protocol of SocialGnutella (協議)
 The protocol is based on Gnutella v6.0, which runs on top of TCP/IP, and enables
two nodes to communicate with each other and share files.
(該協議基於Gnutella v6.0，它運行再TCP/IP上，並允許兩個節點互相共享檔案進行通訊)
 The protocol is composed of the following three steps:
(該協議是由以下三個步驟組成:
1. Establishing a connection. (建立連接)
2. Searching for a file. (搜尋檔案)
3. Transferring file. (傳輸檔案)
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1. Establishing a connection. (建立連接)
 節點建立與當前有效的超級節點連接。
 如果節點沒有朋友那它就會以遊客方式加入超級節點座連接。
 如果朋友們都是活躍的超級節點，該節點發送連接請求連絡人列表中其中一個)
2. Searching for a file. (搜尋檔案)
 當節點建立連接後，它可以發送一個查詢(一個檔案要求)到超級節點。
 超級節點/廣播查詢訊息到期鄰近超級節點和節點
3. Transferring file. (傳輸檔案)
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