在分波多工星狀光纖網路之資料封包排程方法

Packet Scheduling in WDM Star Optical Networks

鄔宜學(Yi-hsueh Wu)

指導教授 ： 蔡榮宗

國立臺灣師範大學/理學院/資訊工程研究所/碩士(2009年)

摘要

在分波多工光纖網路的環境下，使用者各自藉由光纖為媒介連結到一個耦合器，透過其傳輸資料封包，而一條光纖的頻寬又可依據波長被分成多個資料頻道，提供給多組使用者同時接收與傳輸資料封包之用。為了同時處理多個使用者的資料頻道分配問題；避免兩組以上的使用者資料封包同時在同一個資料頻道傳輸而發生衝突，系統需要協定一種資料頻道分配方式來有效的分配頻道給使用者。
除了資料頻道分配方式之外，我們認為決定各個使用者資料封包的傳輸順序也是一個值得研究的方向。例如避免兩個以上的相同目的端資料封包同時被傳送造成碰撞，將其傳送時間錯開，或者優先排程長度短的資料封包，以降低系統整體平均的封包延遲時間。在本論文中，我們主要討論使用者資料封包的傳輸順序方法，我們基本上根據最短資料封包優先 (Shortest Message First)，以及考慮各個使用者接收器的最早可用時間 (Receiver Available Time) 的概念，設計了兩種資料封包排列順序方式，我們發現將之與資料頻道分配方式結合的排程方法，可以使平均的封包延遲時間減少。

關鍵字

分波多工 ； 光纖網路

並列摘要

A distributed packet scheduling scheme is essential for optical star coupler WDM networks, in order to avoid packet collisions that may occur when two or more packets are transmitted over the same wavelength channel at the same time or sent to the same destination node over different wavelengths simultaneously. Besides, it is important that the scheme is able to achieve high efficiency of throughput. In the thesis, we investigate the effect of packet transmission ordering with some well-known channel assignment schemes on packet delay-throughput characteristics. We assume that each node has a fixed transceiver over one wavelength for access and control and a pair of transmitter and receiver that are fully tunable over all wavelengths for payload. Our scheme involves the method of Earliest Available Time Scheduling (EATS) for channel access that of contiguous destination and receiver available time scheduling for reducing receiver tuning time, and that of our transmission ordering that takes short message first and with grouping and spreading that disperses the schedule of packets of the same length in different algorithm execution cycles achieves the best delay-throughput characteristics.

並列關鍵字

WDM ； Optical Networks

參考文獻

[1] M. N. Ransom and D. R. Spears, “Applications of Public Gigabit Networks”, IEEE Network, Mar. 1992.

[3] C. A. Brackett, “Dense Wavelength Division Multiplexing Networks: Principles and Applications”, IEEE Journal on Select Areas in Communications, vol. 8, pp. 948-946, Aug. 1990.

[4] P. R. Trischitta and W. C. Marra, “Applying WDM Technology to Undersea Cable Networks”, IEEE Communication Magazine, pp. 62-66, Feb. 1998

[5] B. Mukherjee, “WDM-Based Local Lightwave Networks Part I: Single-Hop System”, IEEE Networks, pp. 12-27, May 1992

[6] I. Chlamtac and A. Ganz, “Channel Allocation Protocols in Frequency-Time Controlled High-Speed Networks”, IEEE Transaction on Communications, vol. 36, pp. 430-440, 1988.