閘道式行動網路之路由最佳化

Abstract

行動網路在漫遊過程中至今仍有許多限制，如：三角繞徑、換手延遲及封包遺失等問題。本篇論文將著重在路由最佳化的探討，並提出一個可行方案來解決行動網路中三角繞徑的問題。除了行動網路中的戶籍地代理站、外籍地代理站、行動主機及對應節點外，本方案將新增一個功能實體叫做快取代理站。快取代理站本身是一個網路閘道器，並在行動網路中擔任行動代理站的角色，用以支援行動主機及對應節點之間的路由最佳化。在此架構下，所有的對應節點並不需要修改其作業系統的核心部份也不需要額外安裝行動軟體以支援路由最佳化。藉由部署快取代理站，本方案可以避免三角繞徑問題的發生，並且可以明顯的改善行動主機及對應節點之間的傳輸效能。

Mobile IP has some limitations due to triangle routing, handoff latency, and packet lost during handoff process. In this thesis, we will focus on the route optimization and propose an approach to solve the triangle routing problem in Mobile IP network. In addition to home agent, foreign agent, mobile node, and correspondent node, we add a new functional entity, called Cache Agent (CA), to our approach. The CA is a gateway and functions as a mobility agent in the correspondent network to support route optimization between mobile node and correspondent node. In this architecture, all correspondent nodes do not require installing any mobility software to support route optimization. By deploying CAs in the network, the triangle routing problem can be eliminated and the throughput between mobile node and correspondent node can be improved.