On the Design of Micro-Mobility Scheme for Mobile Networks

由90年代以降，隨著製造技術與材料科學的進步，越來越多的行動裝置進入了每個人的日常生活，而另一方面，網際網路的成長使人類的生活及相互溝通更無遠弗屆。此時，因為無線通訊技術的發展，使兩者結合在一起，造就了隨時與隨地，使用者都可以運用手邊的行動裝置來存取網路的現象。但以目前的發展看來，絕大部份的應用及通訊協定的限制，都使得這些行動裝置僅具有可攜性(Portable)，尚不具備移動性(Mobility)，不過這絕對是未來的發展方向。為此，學界也早在90年代就以發展出行動IP(Mobile IP)的技術，冀望能使各種行動裝置能夠達到真正具有移動性，使用者正在使用服務都可以不間斷。所以伴隨著裝置移動(Host Mobility)而來的許多管理上的問題，也已經有相當多的研究著墨於上，這些研究即是通稱的移動管理(Mobility Management)領域的範疇。而這個領域中最新的話題之一便是裝備移動的下一步：網路移動(Network Mobility)。起因於當大量具有無線通訊能力的裝置聚集在一個小範圍當中，這些裝置同時存取網路的過程是有些重覆的行為，而網路移動欲解決的問題便是將這些重覆的行為化繁為簡，以期能夠達到最佳的效率使用。這個問題的標準規範是於2003年出爐的NEMO(Network Mobility) Basic Support為準則。但是由於該規範只是一個較為基礎的標準，當中有許多未盡之處，所以還有改進的空間。 本文的貢獻在於將原本沒有微網域(Micro Domain)的NEMO Basic Support(NBS)加入了微網域的概念，同時提出了一個改進方法，來改善因為加入微網域後所隨之而來的問題。目標就是希望能改進NBS規範當中的缺失，讓所有使用者在使用當中能真正達到更快，更無縫(seamless)的使用體驗。 在實驗設計上，我們設定了幾個評量標準，分別是 1. Number of Binding Update 2. Hand-off latency 3. Packet overhead 4. transmission cost 用這些評量標準分別和NEMO、HMIP等等之前已經公布的協定來比較，證明我們所提出的方法的確有較佳的效率。After 90’s, the improvement of production and material, more and more mobile devices become common and more and more people use them everyday. At the same time, the growth of Internet let people communication tightly. So when wireless technology is invented, it bundles mobile devices and Internet, people now can access Internet any time and any place. But because the limit of application and protocol, most mobile devices just have “Portable”, not “Mobility”. For this purpose，”Mobile IP” is proposed in 90’s, we hope it can help us to build a mobile environment. But we need a management scheme to manage more and more mobile devices, so a new field “Mobility Management’was born. Now, the main issue Mobility Management concerned is about “Host Mobility”, but next big issue is “Network Mobility(NEMO)”. Because when everyone has mobile devices, a large number of mobile devices will aggregate at the same place, for example, Bus or boat. Those devices will access internet at the same time, it is an un-efficient procedure, and they maybe access the same entity for the same information. So a new protocol “NEMO Basic Support” is proposed, it is designed for a Mobile Network. But this document is a basic standard, still have many drawbacks. The contribution of our work is combine Micro-Mobility and NEMO. Initially, NEMO do not have Micro-Mobility scheme. And we solve the problems which are result from the combination of Micro-Mobility and NEMO. Our target is improve the efficiency of NEMO, let user can get more faster experience. In our evaluation, we use four criteria 1. Number of Binding Update 2. Hand-off latency 3. Packet overhead 4. transmission cost to evaluate our work is better than previous works第一章 論論...............................................1 1.1 研究景景..............................................1 1.2 文獻回顧..............................................1 1.3 論文結構........................................3 第二章 文獻探討......................................4 2.1移動IP........................................5 2.2 階層式移動IP.....................................7 2.3 網路移動..................................9 2.4 Ohnishi方法....................................14 第三章 Micro-NEMO........................19 3.1 現有NEMO與Micro Mobility結合的缺陷..................19 3.2 Micro-NEMO情境分析.................................20 3.3 Micro-NEMO機制介紹...............................22 3.4 Micro-NEMO Enhance機制介紹.............................29 第四章 模擬結果與討論......................................38 4.1 模擬環境設定.......................................38 4.2 模擬結果與分析........................................41 4.2.1 Number of Binding Update.............................41 4.2.2 Handoff Latency...................................44 4.2.3 Transmission Cost...............................45 4.2.4 Packet Header Overhead.........................47 第五章 結論................................................49 參考文獻...................................................5