Mobile IP-Based Protocol Enhancements for Improving Routing Efficiency and Handoff Latency

[[abstract]]隨著無線網路的蓬勃發展，行動管理機制的提供變得日益重要。兩個重要而有代表性的機制MIP及ROMIP已先被提出來支援行動管理，然而仍受限於三角路由、控制命令過多及機制支援等問題而效率不彰。標準MIP機制下因為三角路由關係使得傳輸延遲、封包遺失問題出現；雖然ROMIP利用位址更新通知CN紀錄使用者目前位址來避免三角路由問題，然而要求網際網路上所有電腦都需支援行動管理是非常困難的，而且控制命令的負擔也變得比較重。 本論文提出兩個改良的行動管理機制分別稱為MRT及HH-MIP。MRT機制改良自MIP可以免除CN亦須支援行動管理功能的困擾，透過支援MRT之路由器減緩三角路由的現象來提高傳輸效率，此機制還具有寬鬆協定部署限制的好處。HH-MIP則嘗試搭配ROMIP以降低控制命令的傳輸量但仍保有ROMIP傳輸效率的好處，模擬及理論分析證明兩個協定能有效降低傳輸路徑及換手延遲。MRT與HH-MIP甚至可以搭配一起執行以得到兩個行動管理機制的優點，包括部署限制及換手控制命令效率等。[[abstract]]Mobility management is important to wireless networks, but increased speed and efficiency are hampered by problems of triangular routing, signaling overhead and binding cache support. Two important and representative approaches, Mobile IP (MIP) and Route Optimization Mobile IP (ROMIP), were proposed to provide mobility management. In the standard MIP mechanism, triangular routing increases transmission delay, packet loss, and additional signaling. ROMIP uses a binding update to inform a corresponding node of the current IP address of the mobile host. This approach can avoid the triangular routing problem and provide a smoother handoff. However, it is very difficult to implement a binding cache in every node of the entire Internet. Moreover, it also results in large signaling overhead. In this dissertation, we focus on proposing two enhancements of MIP, called Mobile Routing Table (MRT) and Mobile IP with Home Agent Handover (HH-MIP), to remove the limitation of protocol support in the corresponding nodes and also enjoy most of the advantages of ROMIP but with only a small increase of signaling overhead. The MRT approach is an efficient mechanism to avoid the triangular routing problem and can easily achieve the desired mobility support without a great deal of protocol deployment in the Internet. HH-MIP reduces ROMIP shortcomings without introduces large signaling cost. The two proposed approaches can further be integrated to enjoy combined advantages of protocol deployment and less signaling overhead.[[note]]博