臺灣博碩士論文加值系統

如何減少 handoff 的中斷率和增加無縫(seamless) handoff 的比率在服務品質(QoS)的控制功能上是一個要的議題，雖然 Cellular IP 將移動性(mobility)區分為局部(local)和廣域的(wide)二部份可以大幅的改善 Mobile IP 的效能，尤其是當 Mobile host 移動頻率很高的時候。但是 Cellular IP 並沒有提供服務品質(QoS)的控制功能而且也需要定時不斷地發出控制信息來確認目前的位置和更新 Cache □的資料。因此，我們首先要建立一條有 QoS 保證的虛擬路徑，一但路徑建立之後，所有的資料封包會由這條路徑傳送。
我們提出一些 QoS 的控制功能機制在建立路徑上，以保證建立出來的路徑是可以有足夠的頻寬傳送資料封包的虛擬路徑。如進入許可功能(admission control)，hanoff頻寬保留(bandwidth reservation for handoff)，資料重送(data retransmitting)，估計會用到的控制訊息數量(estimated quantity of useful control messages) 等方法來增進 Cellular IP 在QoS 控，此外，我們也提出另一種呼叫(paging)方式，快速發現路徑演算法來取代在 Cellular IP 上所用的 Route Cache 和 Paging Cache。而且當handoff 時，重新找路徑以快速發現路徑演算法對原先路徑上的每一點比對出一個最佳的轉折點。

How to reduce handoff drop and increase seamless handoff is a very important issue of Quality-of-Service (QoS) in cellular. Although the Cellular IP which separates local and wide area mobility can significantly improves the performance of existing mobile host protocols (e.g. Mobile IP), especially when mobile hosts migrate frequently, it does not have the ability to support QoS control and needs to emit beacon periodically. Hence, we propose schemes of the admission control, the bandwidth reservation for handoffs, the retransmitting data and the estimated quantity for the useful Request Message to improve the control function of QoS in the Cellular IP. Also we propose another paging way in the Cellular IP, which is, the fast find path algorithm and optimal cross point node. The admission control can limit the quantity of connection in whole networks. The bandwidth reservation particularly used for handoff can reduce the rate of handoff drops. The estimated quantity for the useful "Request Message" ignores the overload with a large number of request messages. The fast find path algorithm and optimal cross point node only apply in the first find eligible routing path. It can reduce the paging time of mobile host and let the mobile host attach fast.

目錄
中文摘要1
英文摘要2
第1章簡介8
1.1.研究動機9
1.2.相關研究11
第2章設計與實作13
2.1.網路模擬環境13
2.2.快速發現路徑演算法14
2.2.1.初始呼叫(paging)14
2.2.2.handoff 呼叫(paging)18
2.3.QoS 控制功能20
2.3.1.資料重送(data retransmitting)20
2.3.2.Handoff 的頻寬保留(bandwidth reservation for handoff )21
2.3.3.進入許可功能(admission control)23
2.3.4.估計會用到的控制訊息數量(estimated quantity of useful control messages)24
第3章模擬結果和效能分析26
3.1.模擬環境假設與規格26
3.2.模擬結果分析29
第4章結論與未來研究方向36
4.1.結論36
4.2.未來研究方向37
參考文獻41

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