多工作状态环形光网络的可靠性评估

Reliability evaluation of ring network with multiple working-states

提出对具有故障恢复和生存能力的大型网络系统的可靠性研究应分多工作状态进行的思想,定义了多工作状态复杂对象的可靠性参数和表征其工作态的性能参数“系统功能值”,并在此基础上给出了多工作状态对象的可靠性评估模型,用于对双环形光纤工业专用网进行了可靠性分析.仿真结果表明:网元服从指数故障分布时,网络规模越大可靠性随环境的恶化降低越快,90节点网络的可用度环境因子为100时比环境因子为1时降低了91%,而30节点时只降低了3%;网元服从威布尔故障分布时网络可靠性随工作时间延长而降低,使用寿命随工作状态要求降低而提高,30节点网络使用寿命在“好”和“一般”要求下,分别比“很好”要求下延长了38%和46%,说明对网络的可靠性研究应分工作状态进行.

It is proposed that survivable large scale network systems with failure-restoration capability should be regarded as having multiple working-states. Reliability parameters and system function-value, a system performance parameter denoting workingstate, were defined for multiple workingstates object （MWSO）. Then an evaluation module for MWSO was presented and used to evaluate the reliability of a dual-ring fiber industry network （FIN）. Simulation results show that when network elements obey exponential failure distribution, the larger the scale of FIN, the quicker its reliability decreases with environment deterioration. The availability of FIN with 90 nodes would decrease by 91% when environment factor varies from 100 to 1, while that with 30 nodes only decreases by 3%. When network elements follow the Weibull distribution, reliability of FIN declines with operation time, and useful life extends with descending of working-state requirement. Useful life of 30-node network under “good” and “normal” requirements are respectively 38% and 46% longer than that of “very good” requirement. This implies that evaluation of network reliability should be performed under assumption of multiple working-states.