在乙太區域網路上提供多媒體服務頻寬保證

Abstract

分散式多媒體應用程式的出現使得區域網路必須對包含聲音和影像的連續 性媒體提供服務品質的保證，而在各種不同架構的區域網路中，乙太網路 (Ethernet) 佔了絕大多數。然而，由於乙太網路無法提供頻寬保證，因 此我們無法用它來傳送限時性的多媒體資料。如果要使乙太網路能提供頻 寬保證，網路的存取狀況必須是可預知的。在這篇論文中，我們提出一個 可以在乙太網路下傳送即時性資料而且是以軟體建構成的方法，這個方法 稱為 "周期信物"。周期信物完全是以軟體為基礎，因此不需要依賴特殊 的網路硬體。 Distributed multimedia applications have created a need for support of QoS guarantees for continuous media such as audio and video over local area network. Among various architectures of LAN, Ethernet has been the dominantone and we believe that it will continue to be popular in the future for itscost- effectiveness. Nevertheless, Ethernet is unable to carry time- constrainedmultimedia data because of its lack of bandwidth guarantees. In order to provideQoS guarantees over Ethernet, access to the underlying network medium has tobe deterministic. In this thesis, we present the design and implementation ofa software-based scheme called Periodic Token that makes it possible to transmitreal-time data in Ethernet. Periodic Token scheme is implemented totally in software and thus doesn't need to rely on any special network hardware.