網路障礙識別之研究-以SDH網路為例

Abstract

近來通訊網路在大小及複雜度方面一直劇烈增加當中，這種持續增加之複雜度對於網路管理與控制將引發嚴重問題。因為障礙是無可避免的，要使系統更具韌性、運作更加可靠，快速偵測、識別及恢復等作業是非常重要的。因此一個即時的網路診斷系統是迫切需要的。本研究會先分析與討論現有之障礙識別方法，從而提出一種新的障礙識別(fault identification)方法，此法以編碼方式與事件相關連(event correlation)方法為基礎，使用因果關係圖模式來描述網路事件之間的因果關係，此方法不僅能同一時間識別多個問題之發生，也能不受干擾警訊之影響。根據模擬之結果，驗證此法之效益與效率皆有一定程度之改良。此外，本研究將探討SDH網路之網管機制，並期望將新的演算法應用於SDH網路上之障礙識別作業。最後會以一個SDH網路為基礎之範例來驗證所提出方法之可行性。

Communication network has increased dramatically in size and complexity for the past few years. For instance , a typical SDH network may consist of hundreds of nodes from various manufacturers with different traffic and bandwidth requirements. The increasing complexity poses serious problems to network management and control. Since faults are inevitable, quick detection, identification and recovery are crucial to make the systems more robust and their operation more reliable. This thesis will first discuss the present methods for fault identification, then propose a novel fault identification scheme based on event correlation. This scheme not only identifies multiple problems at one time but also is insensitive to noise alarms. The causality graph model will be used to describe cause-and-effect relationships between network events. A simulation model of the SDH network will be developed to verify the effectiveness and efficiency of the proposed scheme.