輸入佇列光交換機中具服務品質保證之光暫存器設計

Abstract

在這篇論文中，我們提出了用於光交換機的光延遲線架構，此架構能夠解決資源衝突並且利用多階層優先權佇列來確保封包在傳輸過程中的服務品質。雖然光延遲線架構已被用來解決在光交換機中的資源衝突問題，但由於光具有持續進行的特性使得封包在隨機存取管理時受到相當大的限制並同時增加了封包遺失的機率。更甚者，為了能夠依照不同優先權的封包提供服務品質保證，往往需要數組的光延於線來實現與確保服務品質。因此，我們提出了單點傳播循環的光延遲線架構，它能夠解決輸入佇列光交換機中的資源衝突問題。而為了改善在輸入佇列交換機中因連線頭端阻塞而降低的封包處理量，我們亦改善了單點傳播循環光延遲線架構使其適用於更具有效率的窗框前瞻式排程演算法。除此之外，為了能夠利用一組光延遲線來暫存不同優先權的封包，我們也設計了一套控制法則將光延遲線劃分為許多個邏輯佇列來存放封包。最後，模擬結果顯示單點傳播循環的光延遲線架構能夠有效地在維持服務品質時降低高優先權封包的遺失率，並且此架構能夠容易地在光封包交換機上實作與控制。

This paper presents a quality of service (QoS) enable optical delay line (ODL) architecture to solve the problem of resource contention and support multilevel priority queues in an optical packet switch. ODL has been used in optical packet switches to resolve resource contention; however, the packets travel continuously in ODL limits the management of random access of the packets and increases the packet loss probability. Moreover, multiple ODL sets usually are needed to realize multiple priority queues in order to support QoS. In this paper, a new Unicast Recirculatiion ODL (URODL) architecture is proposed to resolve the output contention problem in an input-queued optical packet switch. To improve relatively poor throughput due to the head of Line (HOL) blocking in the input-queued switch, we modify URODL to support a more efficient window-based lookahead scheduling algorithm. Furthermore, a control strategy is designed to turn a single set of URODL into multiple logical queues to hold different priority packets. The simulation results show our URODL model reduces high priority packet loss effectively with the capability to support QoS. This URODL model can be easily implemented and managed in a fast optical packet switch.