The Implementation and Performance Evaluation of Dynamic Adaptive Multicast WWW System

Abstract

由於網際網路應用的快速發展以及使用人數不斷成長，使得網路硬體頻寬的擴充速度趕不上使用者增加的需求，以致網路使用品質降低、壅塞甚至連線逾時的情形越來越頻繁。本論文中我們實作並分析評估一個與傳統WWW架構相容之動態調適群播傳輸WWW系統，當網頁需求數量大於門檻值時網頁內容以Multicast方式傳送，需求數量少時則以傳統TCP方式傳送。對於瀏覽率高且具有時效性的網頁及影音資訊，此法不僅能減少網路頻寬的佔用，且具有良好擴充性。Internet provides users with ubiquitous information access and World Wide Webs (WWW) are the most popular applications in the internet. Enormous web accesses use out the network bandwidth, thus increasing the transmission delay and decreasing the quality of service. In this paper we explore an adaptive web service scheme which uses multicast to reduce network bandwidth and server overhead, and thus improves the performance of web accesses. The adaptive web server is able to switch responses to clients’ requests from TCP unicast to multicast and vise versa by monitoring the clients’ requests. When the requests meet a threshold, the sever switches to multicast the responses instead of multiple unicasts. It is very useful for hot web pages and audio/video applications.