以分散雜湊表為基礎之點對點系統的區域性及效率的提昇方法

以分散雜湊表（Distributed hash table）為基礎的點對點系統諸如CAN、Chord、Pastry、Tapestry提供了相當有效率且可保證的平台。但既然DHT以一致的雜湊函數均勻地將節點及物件分佈到虛擬空間，同時也破壞了原本節點之間的區域性（Locality）。而以分散雜湊表為基礎的階層式架構如HIERAS、Canon以地理位置將節點分群，大幅地提昇區域性，但它們仍然無法充分地利用階層結構的優點。此外，因為它們不具有可適應性，效能會因系統狀況而有所差異。在這篇論文中，我們提出一個具可適應性並能動態分群的架構—Pharos 。它將階層式架構應用在DHT，並以區域性為準則來均勻地分群。利用Super-peer的特性，它能有效地管理群組，同時仍保留了DHT的特性。由於動態的分群方式，使得Pharos具有可適應性而總是能保持它的區域性與效率。

關鍵字

點對點；虛擬空間；分散雜湊表；覆遞h ；區域性

並列摘要

Distributed hash tables (DHT) based P2P systems such as CAN, Chord, Pastry, and Tapestry, provide efficient platforms with the guaranteed searching performance. But the locality is destroyed since DHTs use a uniform hash function to distribute nodes and objects in the virtual space evenly. The hierarchical architecture based on DHTs like HIERAS and Canon, significantly improves locality by grouping nodes geographically, but they still cannot take full advantage of hierarchy. Furthermore their performances vary with the system status because they are not adaptive. In this thesis, we propose an adaptive architecture with dynamic grouping, called Pharos. It applies hierarchical overlays on DHTs and groups nodes with locality evenly. Pharos manages groups effectively by taking advantage of the super-peer architecture but reserves the load balance guarantee of DHTs. Because of dynamic grouping, Pharos is adaptive and always keeps its locality and efficiency.

並列關鍵字

peer-to-peer ； overlay ； DHT ； virtual space ； locality

參考文獻

[3] S. Ratnasamy, P. Francis, M. Handley, R. Karp, and S. Schenker, “A Scalable Content-Addressable Network,” in Proceedings of SIGCOMM 2001, ACM.

[4] I. Stoica, R. Morris, D. Karger, M. F. Kaashoek and H. Balakrkshnan, “Chord: A Scalable Peer-to-peer Lookup Service for Internet Applications,” in Proceedings of SIGCOMM 2001, ACM.

[5] A. Rowstron and P. Druschel, “Pastry: Scalable Distributed Object Location and Routing for Large-scale Peer-to-peer Systems,” in Proceedings of IFIP/ACM Middleware 2001.

[9] P. Druschel and A. Rowstron, “Past: Persistent and anonymous storage in a peer-to-peer networking environment,” in Proceedings of the 8th IEEE Workshop on Hot Topics in Operating Systems (HotOS 2001), 2001.

[14] L. F Cabrera, M. B. Jones, and M. Theimer, “Herald: Achieving a global event notification service,” in Proceedings of the 8th IEEE Workshop on Hot Topics in Operating Systems (HotOS 2001), 2001.

國際替代計量

以分散雜湊表為基礎之點對點系統的區域性及效率的提昇方法

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