IETF (Internet Engineering Task Force) 制訂了行動IP (Mobile IP,MIP)協定用來支援無線網路環境下的相關標準，根據此協定，行動節點(MN)可自由地於各網域間移動。行動IP協定可以去輔助節點在不同的網域中進行移動，但這樣的機制下仍存在一些換手問題，如三角路由、封包延遲、封包遺失…等，有不同的行動IP的換手機制研究及架構也油然而生，比較著名機制如Mobile IPv6、Fast handover MIPv6及Hierarchical MIPv6(HMIP)等，而這些都能為了特定去解決一些換手問題；而在底層覆蓋範圍中有可能產生的乒乓效應、無線網路裝置的服務節點量有限及有限的無線網路頻寬，而行動節點在覆蓋範圍中換手時就需要去進行有關於負載量的分配決策；而另一方面在由階層行動IP下也可以設定多階層(Multi-Level)的架構，用它來有效減少行動節點對本地代理伺服器(Home agent)及通訊節點（Correspondent Node，CN）的繫結更新訊息（Binding Update）的次數，所以這樣的架構下由於利用不同行動管理機制下去決策節點所要服務的MAP（Mobility Anchor Point，MAP），這樣並不能確保每一個層上的MAP的節點負載量，而這樣的一個問題也是值得去研究的。
　　本研究將包含兩個部分(水平方式與垂直負載平衡的方式)去分析及設計在不同的行動IP中換手的負載平衡機制，首先在水平負載平衡時，我們設計一個LBHS(Load-balanced handover scheme)機制在傳統行動IP下，由於行動節點在覆蓋的範圍中，本機制可以透過廣播訊息，節點所在的行動代理人可以了解附近基地台的前一時刻的行動代理人服務節點數量，進而透過機制可以有效的平均分擔服務量，進而減少未能服務的節點數；在垂直負載平衡方面，MN在多層的階層行動IP下，由於可以使用不同的行動管理機制用來決策行動節點將換手在不同的階層MAP中，但一樣受限在各層MAP的服務節點量有限，論文中設計兩種方法(動態與靜態的方式)讓節點可以去有效利用各階層中的服務量，並進而有效的對服務量進行負載平衡。靜態垂直負載平衡能避免過多的節點集中由少數MAP來進行服務，所以用靜態分割各MAP服務量的方式來設計，避免負載過於集中；動態垂直負載平衡，可以動態調整節點所服務MAP，透過這樣的操作方式，(1)可以讓我們各層MAP的服務量可以較有效的利用；最後透過實驗的結果來評估效能，可以看出在多層HMIP機制下使用我們的方法，(2)可以在網路的效能(平均時間的服務量增加及未服務量可以減少)能有所提升。

　　The Internet Engineering Task Force (IETF) proposed a standard to support Mobile Node (MN) mobility on the Internet. It is the Mobile IP. There are several problems unsolved inside the Mobile IP standard, such as packet lose, packet delay, Ping-Pong effect, and load balancing during MN''s handover from one subnet to another subnet. There are many different versions of Mobile IP to handle the problems. They are Mobile IPv6 (MIPv6), Fast handover MIPv6, and Hierarchical MIPv6 (HMIPv6)…etc. One important problem of Mobile IP is Load Balancing. When the number of MNs allowed to register to the wireless devices is limited, the network needs some schemes to provide load balancing.
Two load balancing schemes are proposed for this issue. 　　
　　Horizontal Load Balancing scheme can be used in Mobile IPv6 or Hierarchical MIPv6. In the overlapping area of signal emitted from adjacent base stations, MN can receive the signal from more than one station. And then, it can register to any one of the base stations. Because a station can service a limited number of MN only, registration at random may cause the load of base stations unbalanced and further blocked service. The horizontal load balancing scheme let MN know the number of hosts serviced in each Foreign Agent (FA) around the MH by advertisement such that the MN can select the best FA to maintain load balancing, and avoid re-registration due to blocked service.
　　The Vertical Load Balancing scheme is developed for multi-level Hierarchical MIPv6. HMIPv6 provides a solution to manage the local movement of MN based on a hierarchical architecture. Multi-level HMIPv6 utilizes several Mobility Anchor Points (MAP) in hierarchy to reduce a considerable number of Mobile IPv6 Binding Update messages (BU) among the MN, Correspondent Nodes (CN), and its Home Agent (HA). Because the number of service node on the MAP is limited. 　　　The Vertical Load Balancing scheme includes two kinds of method: Static and Dynamic Load Balancing Mobility Management. The Static Load Balancing Mobility Management prevents most MNs from serviced centrally by a particular MAP by dividing and adjusting the load of MAPs between upper and lower levels in the hierarchy. Furthermore, the Dynamic load balancing Mobility Management dynamically adjusts the load of a MAP to its neighbor MAPs.Experiment results show that (1) the proposed schemes have high performance on load balancing, and (2) they can reduce the number of MN which cannot be serviced by the MAP.

第一章、緒論...1
　第一節、研究背景與動機...1
　第二節、研究目的...3
　第三節、論文架構...4
第二章、文獻探討...5
　第一節、行動 IP協定概述...5
　　（一）傳統的行動 IP架構...7
　　（二）行動IP的運作原理...9
　　（三）行動IP的換手問題...11
　第二節、行動IPV6協定及運作流程...13
　第三節、階層行動 IPV6協定...16
　　（一）階層行動 IPV6的基本架構與動作原理...16
　　（二）多階層式HMIPV6的基本架構...18
　第四節、相關的負載平衡策略...19
第三章、研究方法...21
　第一節、概要...21
　　（一）水平方式的負載平衡...21
　　（二）垂直方式的負載平衡...23
　第二節、水平方式的負載平衡...24
　　（一）以傳統的行動IP設計一個水平負載平衡的換手機制(LBHS) ...24
　　（二）以LBHS使用在階層行動 IP...27
　　（三）動作原理與演算法...28
　第三節、垂直方式的負載平衡 ...31
　　（一）多階層式HMIP使用不同行動管理機制可能發生的問題...31
　　（二）採用靜態方式去設計垂直負載平衡...32
　　（三）採用動態方式去設計垂直負載平衡...33
　　（四）動作原理與演算法...34
第四章、實驗與分析...40
　第一節、實驗設計...40
　　（一）行動IP網路架構...40
　　（二）多階層式HMIPV6（三層式的架構）...42
　第二節、實驗操作與結果...44
　　（一）LBHS使用於行動IP...44
　　（二）多階層式HMIPV6使用垂直負載平衡...45
　第三節、實作說明與分析...58
　　（一）水平方式的負載平衡...58
　　（二）垂直方式的負載平衡...59
第五章、結論...61
　第一節、總論...61
　第二節、未來展望...62
參考文獻...64

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