無基礎架構的無線網路下基於需求之智慧型群播路由協定

Abstract

在本論文中，我們提出了一個基於需求之智慧型群播路由協定 (IOD-MRP) 。它適用於網路拓樸快速變動的網路，如無基礎架構的無線網路。此協定乃是簡化並改善原核心協助式網狀群播協定 (CAMP) 而發展出來的。兩者主要的差異在於我們的協定不用核心 (core) 這個輔助角色。取而代之的是利用基於需求之接收者觸發程序，動態地建立群播路由，並維持群播族群關係。此外，我們還設計智慧型行動管理程序，以維持並最佳化群播網。此程序會監視群播資料流，以得知群播網的聯結狀態。因此，我們可以減低行動主機移動所造成的影響並最佳化群播網。有了這個智慧型行動管理程序，因封包氾濫所造成的網路控制訊息量也可以減少。在無基礎架構的無線網路中防止封包氾濫是一個很重要的研究主題，而我們的群播協定可以降低封包氾濫的次數。我們以模擬的方式來比較IOD-MRP和CAMP。模擬結果顯示，IOD-MRP比CAMP的封包氾濫次數少了3% 到13%，而且也稍微減低了群播封包的傳遞延遲和群播封包的遺失率。

In this thesis, we present an intelligent on-demand multicast routing protocol (IOD-MRP) which is suited in rapidly changing network environments, such as ad hoc networks. This protocol simplifies and enhances the existing core-assisted mesh protocol (CAMP). The main difference between our protocol and CAMP is eliminating the cores from CAMP. We remove the cores from CAMP and apply an on-demand receiver-initiated procedure to dynamically build routes and maintain multicast group membership. In addition, an intelligent mobility management procedure is used to maintain and optimize the multicast mesh. This procedure monitors multicast traffic and learns about link states of the mesh. As a result, the effect of mobility can be reduced and the mesh structure can be optimized. With this procedure, control messages due to flooding can be reduced as well. Flooding is an important issue in ad hoc networks and our protocol is able to reduce flooding messages. We compare the proposed IOD-MRP scheme with CAMP. Simulation results show that IOD-MRP reduces number of control messages by 3\% -- 13\% compared to CAMP with slightly decreasing packet delay and packet loss rate.