Abstract: It becomes a critical issue to access and quantify the availability of most networks. This paper presents a novel framework to access the availability of end-to-end traffic in the optical transport network. In this framework, the end-to-end traffic is analyzed by serial structure and parallel structure. It just focuses the ring network availability based on SDH technology that has self-healing mechanism. Calculation of availability is made using the failure of optical cables and equipments that are obtained during years-long observation. At last, the applicability of this framework is also examined in actual networks.

Key words: Availability, Mean time between failure(MTBF), Mean time to repair(MTTR)

摘要： 如何评估和量化分析网络可用性已经成为一个重要的研究课题。该文提出了一个评价光传送系统业务可用性模型，在该模型中，端到端的业务可用性是基于链路的串联和并联结构来分析的，研究了具有自愈环保护机制的SDH业务可用性。传输线路和设备的故障率是基于一个较长的时间段内的计算值。该文验证了基于业务的光传送网的可用性分析的可操作性。

关键词: 可用性, 平均故障间隔时间, 平均故障修复时间