論文摘要
隨著網際網路的興盛，越來越多的無線行動裝置產生，所以人們對於能夠
隨時上網的需求也越來越大，所以目前有一些研究是在探討有關於隨意網路與網
際網路連結來擴展無線網路的涵蓋範圍以達成此目的。其中有人提出在Ad Hoc
網路中只要有一部份的MN 可以與基地台做連結，這些MN 可以被挑選當作
Internet Gateway(IG)並且固定發送MRA 通知Ad Hoc 中所有行動節點，其他不能
與基地台聯繫的MN 可以將資料透過IG 傳送到Internet。但是IG 本身也是一個
MN，所以IG 切換是影響網路效能最重要因素，因為在切換的等待時間，Ad Hoc
與Internet 是處於分離的狀態，若這段時間過長會造成效能嚴重下滑，所以如果
可以將等待時間降到最低則能夠達到最好效能。我們提出一些改善方法與結合
L2 trigger，透過結合L2 trigger 讓DG 可以避免以接收RA 當作依據來判斷是否
離開AR 所造成的延遲時間，並且利用BG selection 與AR 決定新DG 產生可以
降低DG 交遞次數。
關鍵字: 隨意網路，閘道

Abstract
With the prosperity of the internet network, there are more and more wireless
mobile devices producing, so people are greater and greater to the demand for internet
access at any time. Some studies that integrate the Ad Hoc network into the internet in
order to achieve the aim of the internet access on the go. Among them someone
proposes that there is a part of Ad Hoc network MNs that can connect with BS, these
MNs can be selected to act as Internet Gateway(IG), other MNs which can not
connect with BS will convey the date to the internet through the IG. But IG itself is a
MN, so IG switching is the most important factor to influence the performance of
network, because at this switching time, Ad Hoc network does not connect with
internet, all MNs must suspend transmission. If this swtiching time is too long, that
will cause the efficiency of the network to glide seriously. Therefore, we propose
some improvement methods and combine L2 trigger to reduce the delay time, and we
utilize AR and BG selection to determine new DG produced to reduce DG switching
times.
Keyword: ad hoc，Gateway

目錄
目錄.............................................................................................I
圖目錄...................................................................................... III
表目錄......................................................................................IV
第一章 導論.............................................................................. 1
1.1 前言...........................................................................................1
1.2 研究動機...................................................................................3
1.3 論文架構...................................................................................4
第二章 相關研究背景.............................................................. 5
2.1 行動式網際網路協定相關名詞介紹.......................................5
2.2 行動式網際網路協定第六版...................................................6
2.3 MOBILE MULTI-GATEWAY SUPPORT................................8
2.4 ACTIVE SWITCHING...........................................................11
2.5 Gateway Switching Time.........................................................13
2.6 RA 與MRA 訊息格式.....................................................................16
第三章 Proposal scheme ....................................................... 18
3.1 改進機制.................................................................................18
3.2 預先式網路閘道切換.............................................................21
3.3 BG selection 演算法...............................................................25
II
第四章 效能分析.................................................................... 27
4.1 效能分析.................................................................................27
第五章 模擬分析.................................................................... 32
5.1 模擬環境與參數.....................................................................32
5.2 模擬結果.................................................................................33
第六章 結論............................................................................ 32
III
圖目錄
圖1.1、AD HOC 網路與INTERNET 網路連結....................................2
圖2.1、DG 偵測出離開AR 便立即停止服務........................................9
圖2.2、新的DG 產生後立即發送MRA................................................................10
圖2.3、發送預先切換訊息加速Gateway 交替....................................12
圖2.4、沒有gateway switching 的RA&MRA 時間表示圖................13
圖2.5、Gateway Switching 切換的原始方式........................................14
圖2.6、.主動式Gateway Switching.......................................................14
圖2.7. RA 與MRA 訊息格式.................................................................16
圖3.1、預先式網路閘道切換................................................................22
圖3.2、 MGR 切換訊息流程圖............................................................22
圖3.3、 AR 接收預先切換訊息處理流程圖........................................23
圖3.4、行動節點接收預先切換訊息處理流程圖................................24
圖3.5、 BG selection 演算法.................................................................25
圖4.1、 Normal Procedure 服務中斷與等待產生新DG 時間...........27
圖4.2、 Active switching 服務中斷與等待產生新DG 時間.............29
圖4.3、 MGR Procedure 服務中斷與等待產生新DG 時間..............30
圖5.1、 MGR VS Normal 封包遺失比較............................................33
IV
圖5.2、 MGR VS Active switching 封包遺失比較.............................33
圖5.3、 MGR VS Normal End-to-End delay 比較...............................34
圖5.4、 MGR VS Active switching End-to-End delay 比較.................35
圖5.5、 MGR VS Normal Overhead 比較............................................36
圖5.6、 MGR VS Active switching Overhead 比較.............................36
圖5.7、GW 數上升Packet loss 比較.....................................................37
圖5.8、GW 數上升End-to-End delay 時間比較..................................37
圖5.9、MGR 與主動式交換的切換次數比較......................................38
圖5.10、MGR 與主動式交換的切換延遲時間比較............................38
圖5.11、MGR 與主動式交換在有無power 環境下的切換次數比較39
圖5.12、 MGR 與主動式交換在有無power 環境下的切換延遲時間比
較........................................................................................................40
圖5.13、平均每一個DG 可服務的封包數..........................................41
V
表目錄
表5.1、模擬參數表................................................................................32

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