在MPLS(Multi-Protocol Label Switching)的架構底下，所提供的限制性路由標籤發送協定(Constraint-Based Routed Label Distribution Protocol，CR-LDP)使得MPLS擁有流量工程與資料服務品質保證(QoS)的功能，其提供當網路在建立具有服務品質保證的傳輸通道時，在所需頻寬不夠時，高優先權的資料流可以去搶(pre-empt)低優先權資料流頻寬的機制，然而單以優先權高低，來作為要不要搶低優先權資料流頻寬的依據，並不能達到網路效能的有效運用與確保網路的服務品質。
因此我們提出了架構在MPLS網路裡，具有協調式頻寬侵佔(Bandwidth Preemption with Negotiation，BPN)的架構，來解決此問題。在BPN的機制裡，高優先權的資料連線在預留其所需頻寬時，在頻寬不足的情況底下，會去Ingress Router，詢問將被侵佔頻寬的低優先權資料連線，是否可以被侵佔，而Ingress Router會去網路連線狀態資料庫(Network Link State DataBase)查詢，低優先權資料連線是否有其他路徑可以預留其傳輸頻寬，假如有的話才允許高優先權資料連線侵佔其頻寬。
我們在支援MPLS模擬環境的MNS(MPLS Network Simulator)上，新增了協調頻寬侵佔的模組，以便模擬BPN與傳統的強迫式頻寬侵佔兩者在不同傳輸等級間，對於平均資料流輸出率(Throughput)，與封包的遺失率(Packet Loss Rate)方面，發現BPN都有明顯比較好的表現。
最後我們在對具有BPN機制的MPLS網路，作了一些網路環境參數方面的假設之後，依據這些假設的變數，計算出BPN的頻寬協調侵佔演算法的複雜度。

In MPLS networks, CR-LDP (Constraint-Based Routed Label Distribution Protocol) provides traffic engineering and QoS (Quality of Service) by distributing labels along the path. One of the innovative ideas in CR-LDP is right in the capability of bandwidth preemption. Bandwidth preemption allows a high-priority traffic flow to pre-empt the low-priority traffic flow when there is not enough bandwidth for conveying the high-priority flow. However, it is not effective in assuring QoS by simply pre-empting the low-priority flow.
Therefore, in the thesis, we present a bandwidth preemption with negotiation (BPN) architecture for MPLS networks. In BPN, a high-priority flow will have to negotiate the bandwidth with Ingress Switch Router (ISR) before it can actually pre-empt the bandwidth being used by the low-priority flow. A network link-state database in ISR is designed to record the remaining bandwidth for each priority class. ISR determines whether a high-priority flow can pre-empt a low-priority flow based on the condition that the low-priority flow is possible to switch to other paths with an equal bandwidth along the path.
In order to evaluate the performance of our proposed BPN mechanisms, we modify the MNS (MPLS Network Simulator) by adding a bandwidth negotiation module. For the comparisons, we design two topologies for simulating the proposed BPN and the traditional bandwidth preemption with force mode. It is observed that the BPN have exhibited better performance in average throughput and packet loss rate than the traditional bandwidth preemption, not matter either a complex or a regular topology is used.
Finally, we analyze the BPN algorithm complexity by some network parameters, and compare the complexity with that of traditional bandwidth preemption

第一章 導論
1-1 研究動機 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 1
1-2 研究方向與方法 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 2
1-3 論文架構 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 3
第二章 多重協定標籤交換式網路(MPLS)相關研究背景 ‥‥‥ 5
2-1 MPLS的發展背景 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 5
2-2 MPLS網路 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 6
2-2-1 MPLS的基本架構 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 6
2-2-2 MPLS 網路潛在的問題 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 10
2-3 關於MPLS的相關研究 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 11
2-3-1 MPLS與差別式服務(Differentiated Service)的整合‥‥‥ 12
2-3-2 關於流量工程問題的解決‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 13
2-4 限制性服務品質保證路由的問題‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 14
第三章 具協調式頻寬侵占(BPN)的架構‥‥‥‥‥‥‥‥‥‥‥ 18
3-1 BPN 控制封包與訊息封包的設計 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 18
3-1-1 BPN 控制封包的設計 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 19
3-1-2 BPN 訊息封包的設計 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 21
3-2 BPN 的傳輸等級定義 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 24
3-3 BPN 架構的設計原理 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 26
3-3-1 BPN 的工作流程 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 27
3-3-2 BPN 的工作模組與互動流程 ‥‥‥‥‥‥‥‥‥‥‥‥ 29

第四章 模擬與結果分析 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 35
4-1 支援 MPLS的MNS模擬器 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 35
4-2 具BPN功能的相關擴充模組‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 38
4-3 具BPN的網路模擬架構與模擬環境的介紹‥‥‥‥‥‥‥‥‥‥ 41
4-4 模擬結果的討論 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 45
第五章 BPN 演算法複雜度的分析‥‥‥‥‥‥‥‥‥‥‥ 58
5-1 複雜度分析的假設 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 58
5-2 演算法的複雜度 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 60
第六章 結論與未來展望‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 62
6-1 結論 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 62
6-2 未來展望 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 63
參考文獻 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 65
索引 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 68

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