Ⅰ型铁路信号安全协议的消息时效性防护机制  

Protection Mechanism for Message Timeliness in Railway Signal Safety Protocal-Ⅰ

作　　者：臧永立[1] 杨霓霏[1] 卢佩玲[1] 王浩[2] 

机构地区：[1]中国铁道科学研究院通信信号研究所,北京100081 [2]中国铁道科学研究院电子计算技术研究所,北京100081

出　　处：《中国铁道科学》2015年第2期79-86,共8页China Railway Science

基　　金：中国铁路总公司科技研究开发计划项目(2013X001-A;2014X003-F;2014X003-E)

摘　　要：借鉴Ⅱ型铁路信号安全协议中EC周期计数时间戳的时效防护原理,在保持Ⅰ型铁路信号安全协议(RSSP-Ⅰ)的帧格式、时序和安全校验措施的基础上改进接收端处理过程,建立RSSP-Ⅰ的消息时效性防护机制。该机制采用对周期计数时间戳进行时效性检查的方法,通过周期计数对准、周期计数检查和定时启动传输延时检测3个环节,实现消息时效性的防护。在分析消息时效性防护机制的安全性和安全处理原则的基础上,确定消息时效性防护机制中可容忍最大时序偏差、启动传输延时检测周期、发出时序校正请求(SSE)之后等待时序校正答复(SSR)的时限、测得的传输延时状态持续正值的最大保持周期数和传输延时检测最大失败次数这5个关键参数的取值方法。经实验室仿真结果表明,该防护机制能够有效地针对传输延时的风险对消息时效性进行安全防护,可进一步提高RSSP-Ⅰ的安全性。With the timeliness protection principle of EC counter time stamp from railway signal safety protocol-Ⅱfor reference,on the basis of maintaining the frame format,time sequence and safety check measures of railway signal safety protocol-Ⅰ（RSSP-Ⅰ）,the handling process of receiver was improved and a further RSSP-Ⅰ mechanism for ensuring the timeliness of safety-related message was put forward.The approach of checking the timeliness of cycle counter time stamp was adopted for the mechanism.Message timeliness protection was realized through three steps,namely,cycle counter alignment,cycle counter checking and the fixed time start of the detection on transmission delay.Based on analyzing the functional and technical safety as well as the safety processing principle of message timeliness protection mechanism,the method was determined for obtaining five key parameters of the mechanism,including the maximum tolerable deviation in time sequence,the interval for starting the detection on transmission delay,the time limit for awaiting Sequence Start Reply（SSR）after the Sequence Start Enquiry（SSE）being issued,the maximum number of cycles for remaining the positive value of the measured transmission delay,and the maximum number of successive failures in the transmission delay detection.The simulation results in laboratory show that the mechanism can effectively protect message timeliness against the risk of transmission delay threat and can further improve the safety of RSSP-Ⅰ.

关 键 词：数字通信 安全数据 消息时效性防护 安全协议 铁路信号 列车控制系统 

分 类 号：U284.48[交通运输工程—交通信息工程及控制] U284.95[交通运输工程—道路与铁道工程]