電信網路即時動態選路技術之研究與設計

Abstract

動態選路法（Dynamic Routing）指電話呼叫過程會依現在網路狀態而變化其路徑的網路選路技術，在先進國家之電信網路也已採行多時，因其網路選路具有彈性，對於整體網路資源利用及服務品質QOS（Quality-Of-Service）之提升等皆有顯著之績效。傳統的固定階層式選路法（Fixed Hierarchical Routing,FHR），迂迴路徑在設計之初已固定，對於現代瞬息多變，話務種類多樣化，又偏離預測值甚多的話務，適應能力較差，接續致使在網路異常時無法發揮高度融通性及適應性。 本研究即在探討即時動態選路方式，並就其分析結果說明合適的網路管理策略。首先收集有關中繼路由成本、路由容量及路由話務情形的資料，再建立路由方式與網路話務容量之函數關係，並考慮網路異常時應能具有容許量，配合網路成本函數，在網路容量最大之條件下，完成整個網路最佳化模式架構。 本篇論文介紹啟發式演算法，以系統模擬法快速求得近似解，產生動態路徑表，並透過容量設計求得最大需求的中繼電路數。 由模擬輸出結果與原始條件確認網路容量運算法則，顯示所提出模式具有處理網路即時動態路徑之能力。

Dynamic routing is the technology for changing the path according to the current network status. This technology has been adopted for many years for telecommunication networks in those developed countries, and its flexibility is very helpful in improving QOS(quality-of- service) as well as enhancing the utilization of whole network resources. For The conventional FHR(Fixed hierarchical routing), the alternative path is set up in the stage of routing design, it is less adaptive for modern changeable and versatile telecommunication networks. This research is to study the way of Real-Time dynamic routing, and to use the analytical results to build up a suitable network management tactics. First of all, we collects the data of trunk cost, the path capacity and path traffic, and builds up the function based on path information and network traffic capacity. Then, according to the network cost function and taking account the space allowed under abnormal network status , we construct an optimization model with the minimum network resource. We introduce an efficient heuristic optimization method for solving the linear programming routing problems, our method greatly improve computational speed with minimal loss of accuracy. From the simulation result, we demonstrate that our model is able to accommodate the Real-Time dynamic routing for telecommunication networks.