由於IPv4位址之缺乏，IPv6快速地發展在許多應用上，對於無線網路服務之應用，行動裝置需要透過行動式IPv6協定所提議的更新連結程序來接取上Internet。隨著越來越多的無線網路應用，許多有關在各網路間漫遊之效能與安全性等問題一一浮現，IETF於移動式網路協定(NEMO)提出解決在不同網路之間漫遊的問題，然而，並未詳細討論有關在移動式網路環境上之效能與安全性問題。我們將利用行動式IPv6對於移動式節點的路徑最佳化(Route Optimization)與更新連結程序(Binding Update Procedure)機制，來解決在移動式網路中效能與安全性的問題。移動式網路可適用於一列搭載許多攜帶無線裝置的乘客之火車，當每個行動裝置為一個行動式節點時，火車可以視為一個移動式網路。如果將更新連結程序運用於移動式網路，更新連結訊息量超越於單純使用在行動式節點的情況。 本論文中，利用多點傳播(Multicast)減少更新連結訊息量以增進更新連結之效率，並藉由模擬環境比較經由行動式路由器之更新連結訊息量、相對應節點資料傳送路徑之狀態及直接路由之比率，分析單一傳播與多點傳播之更新連結方式。此外，我們的研究也考慮到更新快取之存活時間所造成的影響。 IPv6 has been widely deployed to many applications, especially for wireless services, owing the lack of IPv4 address. The mobile devices need to be connected to the Internet through the binding update procedures proposed in the Mobile IPv6 protocol (rfc3775). With more and more wireless applications, many problems appear such as efficiency, security and the movement among the different networks. IETF proposes a method (currently it is still a draft) “Network Mobility, NEMO” to solve the problem of moving among different networks. However, IETF has not clearly discussed the efficiency and the security problems in mobile network environment. We apply the route optimization method and binding update procedure proposed in the Mobile IPv6 for mobile node to solve the efficiency and security problems in mobile network environment. A mobile network can be applied in a fast moving train with many passengers carrying wireless devices. In the condition, the train is regarded as a mobile network while each mobile device is a mobile node with this mobile network. When the binding update procedure is applied to a mobile network, the amount of binding update message will be much more than which of a mobile node. In this thesis, we improve the efficiency of binding update by multicast to reduce the amount of binding update message. We analyze the unicast and multicast binding method by comparing the binding message cost of the mobile router, the states of correspondent node transmission path and the ratio of the direct route based in our simulation environment. The impact of the life time used for binding cache is also considered in our study.
