在本論文中，我們實作出一個符合3GPP之TS 23.203之策略與計費控制(Policy and Charging Control; PCC)系統，策略與計費規則控制系統提供動態的網路管理與即時計費的功能，然而，PCC信令傳遞會大幅增加建立session所需時間，降低建立session的效能，因此我們提出使用快取機制，以減少策略與計費規則控制器(Policy and Charging Rule Function; PCRF) 與用戶設定檔儲存器(Subscription Profile Repository; SPR)間因為傳送使用者資訊所造成的傳送延遲。
　　本論文所提出的快取機制，是屬於弱一致性的快取機制，會在使用者更新其使用者資訊一段時間後，才更新PCRF的快取，如此可以降低使用者過度頻繁更新使用者資訊所造成的系統資源浪費，我們提出了三種T-cache快取機制，Single-user T-cache (ST)、Multi-user T-cache (MT) 以及Multi-user Rule-based T-cache (MRT)，以上三種T-cache皆是基於延遲更新門檻值T來決定是否更新，其中T代表等待更新的使用者資訊數或等待更新的使用者數。而在我們所建立的模擬實驗中，以快取中資料的正確率、快取更新的頻率以及更新的成本來對三種快取機制進行效能分析，由實驗得知，MT與MRT的效能均較優於ST，而若更新集中於少部分的使用者時，MT的更新成本會較小於MRT，但是MRT的資料正確率會較高於MT。而由實驗也可以得到，在策略與計費規則平台中使用快取機制能夠大幅降低建立session的延遲問題。

　　In this thesis, we present the design and the implementation of a test-bed for the Policy and Charging Control (PCC) system proposed in 3GPP TS23.203. The PCC architecture provides dynamic policy control in the packet data gateway combined with real-time charging management in the online charging system. However, long PCC signaling overhead incurred during PCC rule setup degrades the new session initiation performance.　Thus, we propose a cache mechanism to shortern the subscriber profile retrieval delay incurred between two PCC components: the Policy and Charging Rule Function (PCRF) and the Subscription Profile Repository (SPR).
　　Based on the delayed update concept, the cache maintained in the PCRF will update only if certain update criteria is satisfied. Three caching variations, Single-user T-cache (ST), Multi-user T-cache (MT) and Multi-user Rule-based T-cache (MRT), are designed in respect to the delay threshold T, the number of updated profile and the number of updated users. We conduct simulation experiments to investigate the system performance in terms of the cache validity probabitliy, the cache update frequency, and the cache refresh cost. Among three cache variations, both MT and MRT have better performance than ST. When only a small amount of subscribers frequently update their subscriber profiles, the cost of MT is lower than that of MRT; however, the validity probability of MRT is higher than that of MT. In general, our results show that a cache mechinsim can significantly shotern the session setup delays.

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