Kademlia 是一種在點對點（peer-to-peer）網路以以網路拓樸為基礎（Topology-based）的系統，這個系統確保在這個容易錯誤的環境下，資料的一致性和效能的表現。這個系統使用XOR-based方式的拓樸，做為傳遞查詢訊息，和找到特定結點的方法。
但Kademlia的搜尋缺乏實際距離的概念，造成我們在搜尋時，容易造成多餘的時間浪費。針對這個問題，我們在Kademlia上，階層式架構(Hierarchical Overlay)，利用節點間互相的實體距離為資訊，來建構三個階層，以期縮短在搜尋實際距離相近的結點的時間。
關鍵字: 點對點網路、拓樸、階層式架構

Kademlia is a Topology-based peer-to-peer system，has provable consistency and performance in a fault-prone environment. This system use XOR-based metric topology to query and locates nodes.
Because lookup of Kademlia doesn’t consider real distance between nodes, it may make us to waste extra time for searching. For this problem, we construct a three-layered hierarchy overlay by physical distance between nodes to hope to shorten total latency of a lookup.

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