A movable network:two-level mobile IPv4

Mobile IPv4是目前行動IP網路的標準，但仍有triangle routing、handoff延遲、安全性不佳、及Foreign Agent負擔過重等等問題。其中Route Optimization解決了triangle routing的問題；而fast handoff改善了handoff延遲及handoff期間封包遺失的問題。由於Mobile IP的設計是用來提供給個別使用者能獲得不間斷的連網服務(Session Continuity)，所以在許多情形下，例如公共運輸系統的上網服務，並不能達成最大效益。 本文考慮在IPv4的Mobile Network環境下，MN (Mobile Node)本身具備Mobile IP功能，且MN註冊的FA (Foreign Agent)也可以移動時。依據Mobile Gateway ( Foreign Agent of Mobile Node)以及MN的Care-of Address種類( Foreign Agent Care-of Address或是 Co-located Care-of Address) 的不同組合，共有四種可能的雙層Mobile IP移動網路架構，並提出一個適合實際環境的使用雙層Mobile IPv4架構的移動網路。 本文提出並分析了所有使用雙層Mobile IP的可移動網路的架構。在不變動Mobile IP原有協定情況下，減少MN直接與遠端未知FA註冊的需求，增加MN的安全性，並可減低FA的負擔。同時MN可依實際狀況自由選擇最適合的網路來連結，增加用戶的便利性，並達到最佳的通訊連結效果。此外，本文也舉出其相對應的Route Optimization及Fast Handoff的機制，以期達到最大效益。Mobile IPv4 is the standard of current IPv4 Mobile Network. However, it still has some problems, such as triangle routing, handoff delay, insecurity, and foreign agent's heavy loading. Route Optimization has solved the triangle routing problem, and fast handoff has improved the situation of handoff delay and packet loss during handoff process. Even many proposals resolve some of these problems, Mobile IPv4 not meet the requirements of seamless handoff (Session Continuity) in some situations such as the internet access of bus passengers. This article has considered all possible combination of Care-of Address types of MN and MG (Co-located Care-of Address and Foreign Agent Care-of Address), and proposed the structure called “Multilevel Mobile IPv4” where the Foreign Agent (FA) of MN, called Mobile Gateway, moves together with MNs when many MNs moving together. As Mobile IPv4 protocol remains unchanged and the legacy MN can also work under its condition, this structure can decrease the opportunities of MN directly registering a remote foreign agent, increase MN's security and reduce FA's loading. Meanwhile, MN could also select the best effort network regarding current condition to improve user's facility and to reach the best transmission quality. In the other hand, Route Optimization and Fast Handoff mechanics are also demonstrated in each case mentioned above to improve the performance of packet routing and handoff procedure.摘要 i Abstract ii 目錄 iii 圖目錄 vi 表目錄 viii 第一章 緒論 1 第二章 相關技術 3 2.1 背景知識 3 2.1.1 Mobile IPv4 3 2.1.2 Route Optimization 9 2.1.3 Fast Handoff 12 2.2 相關研究 13 2.2.1 Mobile IPv6 13 2.2.2 NEMO 14 2.2.3 Micro Mobility及其他Mobility方案 16 2.3 待解決的問題 17 第三章 系統架構 19 3.1 MG與MN之CoA皆為FACoA 19 3.1.1 系統架構 19 3.1.2 註冊訊息 21 3.1.3 封包傳遞 22 3.1.4 Route Optimization及Fast Handoff 23 3.2 MG與MN之CoA分別為CCoA及FACoA 26 3.2.1 系統架構 26 3.2.2 註冊訊息 27 3.2.3 封包傳遞 28 3.2.4 Route Optimization及Fast Handoff 29 3.3 MG與MN之CoA分別為FACoA及CCoA 31 3.3.1 系統架構 31 3.3.2 註冊訊息 32 3.3.3 封包傳遞 33 3.3.4 Route Optimization及Fast Handoff 35 3.4 MG與MN之CoA皆為CCoA 36 3.4.1 系統架構 36 3.4.2 註冊訊息 37 3.4.3 封包傳遞 38 3.4.4 Route Optimization及Fast Handoff 39 第四章 比較與分析 41 4.1 各個雙層Mobile IPv4架構移動網路的比較 41 4.2 使用雙層Mobile IPv4的效益 42 第五章 總結 44 參考文獻 4