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標題: | 資料於P2P網路上之一致性 Data Consistency in the Structured Peer-to-Peer Network |
作者: | Cheng-Ying Ou 歐政穎 |
指導教授: | 黃寶儀(Polly Huang) |
關鍵字: | 分散式雜湊表,同儕網路檢索系統,同儕網路,資料一致性, peer to peer,P2P,distributed hash table,DHT,data consistency, |
出版年 : | 2007 |
學位: | 碩士 |
摘要: | 現今已有很多增進同儕網路搜尋檢索的方法被提出,大部分被提出的搜尋檢索方法像是Chord、Pastry、或是Kademlia都是基於分散式雜湊表(DHT)。這些使用不同分散式雜湊表演算法的系統都擁有著不錯的檢索效能。由於同儕網路不安定的特性,這些系統為了要保護資料不軼失都會保存多筆相同的複製資料。然而,這些資料在被頻繁的修改動作下,有可能產生了數筆應是相同的資料卻有不同值的問題。為了避免這個資料不一致的問題,已經有許多達到資料同步的演算法被提出。此篇論文的目的就是去深入了解這些增進資料一治性的演算法。為此,我們實作了一個資料一致性演算法於Chord這個知名的同儕網路檢索搜尋系統上。藉由數個系統化的模擬實驗,我們發現了:(1)就算是在亂度很高的網路狀態下,不管有無加入資料一致性演算法,資料的可獲得程度幾乎都相同;(2)資料的不一致性程度也有類似的結果,就算亂度相當高,兩者之結果也幾乎相同。從實驗結果我們可得知,實作資料一致性演算法於同儕網路檢索搜尋系統上似乎是不必要的。此篇論文結果的發現,對資料一致性於同儕網路檢索搜尋系統上提供了一些實作上的參考建議。 There has been a great body of work that proposes mechanisms to enhance the search efficiency of P2P file sharing systems. Prominent systems such as Chord, Pastry, and Kademlia utilize the concept of distributed hash tables (DHT). These systems, using one of DHT or another, are shown to be efficient at looking up arbitrary files in large-scale P2P networks. To handle churns commonly seen in P2P systems today, most of these systems replicate files and maintain the replicas in accordance to the DHT in use. When the files, or more generally the data, are frequently updated, the data consistency in between replicas becomes a rising problem. To overcome this problem, a number of proposed mechanisms are proposed which aim at keeping the data replicas consistent. To obtain a better understanding of how these kinds of enhancements help improve data consistency, we implement a replica consistency enhancement on a prominent DHT-based peer-to-peer system. Through a set of systematic simulations, we find that: (1) the availability of data of Chord with the replica consistency enhancement is the same as Chord without the enhancement, even when the churn rate is high; and (2) Chord without the enhancement and Chord with the replica consistency enhancement have no inconsistent data, even when the churn rate is high. As the result, the replica consistency enhancement appears to be overkill given its implementation complexity. Our findings in this work provide insights into the making of cost-effective design decisions for P2P mutable file sharing systems. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/24913 |
全文授權: | 未授權 |
顯示於系所單位: | 電機工程學系 |
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