在網際網路視訊傳輸服務之快取伺服器中提供一個有效的快取及傳輸速率調整方法

Abstract

網際網路和相關服務的發展已經深遠的改變了人們的生活。隨選視訊的應用也大量的成長。但此類的服務往往會由於本身大量的頻寛使用和儲存空間需求而成為網路的瓶頸。為了要解決這個問題，我們在本篇論文中提出一個視訊快取伺服器的架構。為了讓快取伺服器中快取資料的命中率提高，我們針對每一部影片的受歡迎程度儲存部份的資料。此外，我們利用Fibonacci 函數將多媒體資料切割成不同大小的片段。藉由這個切割方式，我們可以增加資料配置及代換的速度。在多媒體資料的傳輸時期，我們利用指數函數提出一個新的傳輸速率調整機制。這個方法可以增加可用頻寛的使用量以及減少資料遺失的比例。根據初步的分析和模擬結果的成果評估可以得知我們的方法與其他的類似方法相比具有正面的效能改善。詳細的設計原理、運作流程以及效能評估將會在論文往後的章節中一一介紹。

The advances in Internet and related services have changed human’s life. The application of multimedia-on-demand also grows up dramatically. However, this kind of services may cause the bottleneck of Internet due to the bandwidth requirement and storage constraint of multimedia data. In order to resolve this problem, we propose the streaming proxy architecture in this thesis. We place a streaming proxy that is close to clients, and the proxy forwards and caches frequent and popular video programs according to the viewing behavior of clients. The cache-hit rate should be high in order to reduce the load of network and response time of client. To achieve this goal, we store portions of each video program according to its popularity. Additionally, we use Fibonacci function to divide the video data into variable-sized segments. By this way, we can speed up the data allocation and cache replacement. During the transmission of video data for each session, we also propose a new transmission rate control mechanism based on exponential function. It can achieve higher bandwidth utilization and lower data loss rate. According to our preliminary analysis and performance evaluations by simulation, we can show that our techniques have positive results compared with other similar methods. The detail information will be given in the contents.