对等通信中的缺失片段综合征
The Missing Piece Syndrome in Peer-to-Peer Communication
摘要：
用于在因特网上进行对等文件共享的典型协议将待共享的文件分成多个部分。新的同行努力从其他同行和种子中获得完整的作品集。在本文中，我们调查的问题，可能会发生，如果播种率不够大。问题是，即使系统的统计数据是对称的，对称性也会发生破坏，其中一部分变得非常罕见。如果同伴在获得完整的收藏品后离开，他们可能会在帮助其他同伴获得稀有的藏品之前离开。假设对等体到达时没有片段，存在单个种子，进行随机对等体接触，下载随机有用片段，并且对等体在接收到完整文件时离开，如果播种速率（以每时间单位的片段为单位）大于到达速率，则系统是稳定的，并且如果播种速率小于到达速率，则系统是不稳定的。结果对于从有用的片段中选择的任何片段选择策略都是持久的，例如最稀有的优先，并且它通过使用网络编码而持久。
英文摘要：
Typical protocols for peer-to-peer file sharing over the Internet divide files to be shared into pieces. New peers strive to obtain a complete collection of pieces from other peers and from a seed. In this paper we investigate a problem that can occur if the seeding rate is not large enough. The problem is that, even if the statistics of the system are symmetric in the pieces, there can be symmetry breaking, with one piece becoming very rare. If peers depart after obtaining a complete collection, they can tend to leave before helping other peers receive the rare piece. Assuming that peers arrive with no pieces, there is a single seed, random peer contacts are made, random useful pieces are downloaded, and peers depart upon receiving the complete file, the system is stable if the seeding rate (in pieces per time unit) is greater than the arrival rate, and is unstable if the seeding rate is less than the arrival rate. The result persists for any piece selection policy that selects from among useful pieces, such as rarest first, and it persists with the use of network coding.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
