节点非独立失效下的局域网可靠性建模与分析

以具有层次结构的局域网作为拓扑模型,考虑共因失效和关联失效这2类节点非独立失效事件发生的情况,建立了交换机节点失效模型来模拟交换机失效,利用Monte-Carlo仿真算法近似计算出网络的两端可靠性,研究2种共因失效事件和3种关联失效事件对网络端端可靠性的影响。结果表明:因资源节点出现故障和协议层出现错误而导致交换机失效的共因失效事件均会降低网络可靠性,且资源节点失效概率或协议层失效概率越大,网络可靠性越低;而由于使用了热备份技术、堆叠技术以及发生广播风暴导致的关联失效事件,即使节点独立失效概率很小,只要相关因数足够大,故障都会快速传播,导致网络可靠性迅速下降。

Modeling and Analysis of Reliability for Local-area Networks with Dependent Failures of Nodes

Based on the LAN which has a hierarchical structure and considering two types of independent failure of nodes： common cause failure and escalating failure, the node failure model is created to simulate the switches failure. Using Monte-Carlo simulation （MCS） to calculate the reliability and analyzing the impact of two kinds of common cause failures and three kinds of esca- lating failures on reliability. It is shown that common cause failures which result from switch failure because source nodes or net- work protocol layer can decrease reliability, and reliability decreases with failure probability of source nodes or network protocol lay- er increases. Moreover, it is proved that escalating failure resulting from hot backup technology, switch stacking technology or broad- cast storm can affect other nodes rapidly and cause rapid decline of network reliability.