网络服务系统可生存性分析与验证

为了分析采用冗余组件的网络服务系统的可生存性，建立了攻击、抵抗和恢复的过程模型，基于服务与组件的依赖关系提出了系统可生存性的量化评估方法.分析了不同组件的系统可生存性评估值的敏感参数及贪心策略下的恢复优先级，采用着色Petri网设计了仿真工具，并以一个IPTV网络服务系统为例，验证了攻击强度、攻击密度和恢复强度对系统可生存性的影响.该方法将可生存性系统的运作过程建模为多种因素并行作用下的动态过程，并利用仿真工具对系统的可生存性进行了验证，其验证结果为可生存系统设计及可生存性增强策略提供了依据.

Analysis and validation of survivability for network service system

In order to analyze the survivability of network service system with redundant components, an attack resistance recovery process model was established, and a quantitative assessment method for system survivability was proposed on the basis of the dependency relationship between service and components. The sensitive parameters for the assessed values of survivability and the recovery priority under greedy strategy for the system with different components were analyzed, and the simulation tool was designed with the coloured Petri net. In addition, the effect of attack intensity, attack density and recovery intensity on the system survivability was validated through taking an IPTV network service system as an example. With the proposed method, the operation process of survivable system was modeled as a dynamic process under the parallel action of multiple factors, and the system survivability was validated with the simulation tool. The validation results can provide the referrence for the design of survivable system and the enhancement strategy of survivability.