臺灣博碩士論文加值系統

網路電話的出現，讓原本利用公共電話網路傳遞語音訊號之模式，改成將語音訊號壓縮成數據封包，利用網際網路來進行傳送，然而，網路電話的主要問題之一，就是能否提供如傳統電話之服務品質，因此提升服務品質之技術逐漸地受到重視。在目前的服務品質協定中，MPLS利用標籤交換的方式，解決路由器轉送速率的問題，但是在大量使用網路電話的情況下，網路壅塞的情況仍然存在，造成了延遲、抖動以及封包遺失，影響網路電話之服務品質。因此在本論文中，提出了一個新的主要路徑切換機制，利用SCTP Multi-Homing的特性來進行傳輸，並透過SACK機制即時地回報主要路徑的傳輸狀況，在網路狀況不佳的情況下，適時地切換至其他路徑進行傳輸，達到提升VoIP服務品質之目的。

VoIP has been a prevalent application nowadays. It allows us to transmit voice data over IP network. However, QoS is a major challenge of VoIP. It must provide like traditional conversation quality. Therefore, QoS protocols are paid attention gradually for real-time applications. MPLS is the important technique to improve the network performance from QoS view point. It utilizes the Label Swapping to speed up packet forwarding. However, when a large number of users use VoIP service, the network congestion still exists. It caused the delay, jitter and packets lost that influenced the QoS. In this paper, we proposed a new primary path switching strategy. Using SCTP SACK mechanism to report the QoS parameters of primary path and to determine whether to switch to backup path or not. The simulation results of the proposed strategy also show significant improvement in VoIP QoS.

第一章、 緒論 1
1.1 研究背景 1
1.2 研究動機與目的 2
第二章、 文獻探討 4
2.1 服務品質概論 4
2.2 服務品質協定 5
2.2.1 RSVP 5
2.2.2 DiffServ 7
2.2.3 MPLS 8
2.2.4 服務品質協定之比較 12
2.3 服務品質衡量指標 13
2.4 串流控制傳輸通訊協定 17
2.5 服務品質之相關研究 22
第三章、 系統設計 25
3.1 系統架構 25
3.2 系統設計 26
3.3 服務品質取樣演算法 34
3.4 主要路徑切換策略 36
第四章、 效能分析 40
4.1 模擬場景 40
4.2 模擬結果與分析 41
4.2.1 與其他協定之效能比較 41
4.2.2 多路徑之效能分析 44
4.2.3 取樣週期時間之微調 48
第五章、 結論與未來研究方向 50
5.1 結論 50
5.2 未來研究方向 51
5.2.1 整合式網路電話服務 51
5.2.2 取樣週期時間之動態調整 51
5.2.3 系統實作 53
參考文獻 55

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