論文摘要 由於網路上多媒體即時傳輸及各種寬頻網路應用的發展日新月異，Internet 對於多媒體通訊服務如WWW embedded or plug-in 、Real time Voice /Video ，電子商務，網路電話(IP-Telephone) 、WebTV …等的要求與日俱增，對於高速網路的需求日益殷切，雖然Optical Fiber 的鋪設提高了主幹的頻寬，但對於指數成長的網路流量仍不敷所需。 近年來高密度分波多工技術（Dense Wavelength Division Multiplexing-DWDM）的發展，以高密度的分波多工器及光放大器所組成的光纖網路，已經對傳統的傳輸網路帶來了革命性的改變；它不僅大大地提昇了骨幹傳輸網路的頻寬，而且降低網路費用以及使網路傳輸系統的控制維護趨於簡單。但傳統Sonet/SDH Circuit Switch 的傳輸型態Over head 較大，降低了整體的效能而為了簡化通信協定，提高傳輸效能IP over DWDM的應用也因應而生 。 傳統IP V4 的網路只提供了best effort 的傳輸服務，對於資料型態多元化，服務要求複雜化的Next Generation Optical Internet 實是不敷所需。因此在DWDM 上建立一套完整的QoS機制，便成為建制All Optical Network 的熱門話題，尤其在經歷IP over ATM 數年來的研究，以及MPLS 的發展，QoS in Internet 已是大勢所趨，未來提供QoS的網路管理將是一大課題。 所以如何透過簡單的機制來有效管理QoS in DWDM Network 及增進IP over DWDM的傳輸效能，簡少Optical buffer的需求便是我未來研究的目標。 Abstract: Dense Wavelength-division multiplexing has emerged as an important physical layer technology. Optical transmission provides a physical layer capable of carrying bits at the speed of the order of a gigabit per second. Optical burst switching is proposed to overcome the shortcomings of conventional WDM deployment, such as lack of fine bandwidth granularity in wavelength routing and electronic speed bottlenecks in SONET/SDH. In this article, we describe an architecture for IP network over the OBS DWDM transmission core. The use of MPLS-type technique for forwarding data bursts and the inclusion of a medium access control layer between the optical (DWDM) and IP layers are the key ingredients of the proposed architecture. In particular, the architecture is based on provisioning MPLS paths, also called label switched paths, of desired quality of service through the OBS WDM transmission core. The MAC layer performs various OBS-specific functions, such as burst assembly, burst scheduling, and offset setting/traffic shaping. While burst assembly and burst scheduling are relatively straightforward, we point out that the offset setting strategy has significant impact on the performance of IP network operating over OBS DWDM core. We describe a shaping scheme to set the offset, an important system parameter for OBS, between the successive data bursts of a given data stream (label switched path) and their associated control packets. This scheme results in robust operation of the network and also facilitates traffic engineering. Guidelines are provided for implementing various IP QoS mechanisms in the optical backbone using OBS.
