內容遞送網路(CDN)提供了經由內容提供者合法授權的終端使用者就近取得內容服務。內容提供者不需要額外花費硬體設備與網路頻寬的建置，將內容遞送的工作委託給內容遞送網路服務業者，大幅降低了設備成本與網路頻寬的浪費。但是對於內容遞送網路服務業者而言，大量的儲存設備建置以及多媒體需求，帶來更多的網路頻寬的租用，造成龐大的資本支出。 另一方面，在點對點傳輸網路下，任何終端使用者都能將本身所擁有的內容分享給網際網路上的任何使用者，而不受到任何約束。因此點對點傳輸網路下，並不在意內容是否經過合法授權傳遞。換言之，內容提供者無法掌握內容傳遞狀態以及其他合法使用者權益的保障。再者，點對點傳輸中，必須至少有一份完整的內容種子(seed)存在，才能確保內容得以完整取得。 本論文將針對內容提供者權益的保障，也就是不論經由內容快取伺服器或使用者快取下載，都必須先向原始內容提供者報到，提出在複製可追查型CDN-P2P架構下的近端快取伺服器選擇法。在此架構下，所有遞送服務都必須先向內容提供者報到，才能行使遞送服務。並假設內容遞送網路服務業者可以透過一套獎勵回饋機制，吸引使用者加入使用者快取的遞送服務。我們使用地標點為基礎的兩階段伺服器選擇方式：第一階段，終端使用者透過前端內容遞送網路找到近端內容快取伺服器；第二階段則是由內容快取伺服器查詢提供近端使用者快取服務。在此架構下，由於終端使用者必須經由內容提供者指派內容遞送網路才可得到內容下載服務，不管是經由內容快取伺服器或是使用者快取；因此內容提供者權益得以保障。最後，在兩階段的近端伺服器選擇法中，能夠找到最靠近使用者端的伺服器提供服務。 Content Delivery Networks (CDNs) services by distributing content to replica servers located close to users. The content provider entrusts the delivery of CDN service provider to avoid the extra cost for network equipment setup and reduce the need of the bandwidth. However, CDN service provider has to spend huge capital expenditure to deploy and maintain hardware device. On the other hand, under Peer-to-peer (P2P) Network, anyone could share his content to other users without restriction. Therefore, P2P Network does not care whether the content is authorized legally to transmit or not. In another words, the content provider in P2P system is unable to understand the delivery status and the right using of replication. Moreover, a P2P system requires sufficient number of the seed to guarantee that the content can be transmitted intactly. In this paper, we proposed a selection procedure to find the nearest server in the replication-aware CDN-P2P system, and to protect the content provider’s rights. In the meantime, we suggested that CDN service provider could provide an approach for end users to join the delivery service through the positive feedback rewarding, and the P2P program must get authorized replication right to enable delivery service. We chose two-step selection approach on landmark-based selection algorithm: (1) the end user finds the nearest content replica server through the content delivery network, (2) the end user gets the nearest peer cache by the content replica server. Under this proposed architecture, everyone must be authorized to download content via the content provider, no matter the content is from replica server or peer cache. Therefore we could guarantee the copyrights of contents and the two-step server selection approach could offer the nearest replica /cache server to the end users.
