Railway systems are composed of a multitude of subsystems, sensors, and actuators that exchange datagrams through safety-critical communication protocols. However, the vast majority of these protocols rely on ad hoc interlacing mechanisms and safety codes which raise the heterogeneity and complexity of the overarching railway system. Therefore, Rete Ferroviaria Italiana, the company who is in charge of managing the Italian railway network, coordinated the definition of the Protocollo Vitale Standard (Standard Vital Protocol). This protocol is inspired to, and compliant with, the communication protocols adopted for the European Train Control System (ETCS) (SUBSET, UNISIG, 037, Euroradio FIS, version 2.3. 0; SUBSET, UNISIG, 098, RBC-RBC safe communication interface, 2007), and it is meant to become the standard layer to enable safe communication between components of the Italian railway system. This paper reports our experience in the design, implementation, verification, and validation of the Protocollo Vitale Standard in compliance with the European safety standards for railway systems. We first defined a safety plan and a verification and validation plan, which guide the design, development, verification, and validation activities as required by safety standards. Guidelines of such plans have been followed strictly until completion of the work, which concludes with the provision of a safety case where all safety evidences are summarized. Noticeably, we (i) selected appropriate safety mechanisms, (ii) verified the software design, (iii) implemented the software in compliance with code metrics and coding rules, (iv) conducted tests to validate the protocol against its functional and performance requirements, and ultimately (v) devised all relevant documentation and a safety case which summarizes the evidences needed for certification.

中文翻译：

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开发和验证符合铁路标准的安全通信协议

铁路系统由通过安全关键型通信协议交换数据报的大量子系统，传感器和执行器组成。但是，这些协议中的绝大多数都依赖于临时的隔行扫描机制和安全代码，这会提高总体铁路系统的异构性和复杂性。因此，负责管理意大利铁路网的公司Rete Ferroviaria Italiana协调了协议规程标准（Vital Protocol Standard，标准重要协议）的定义。该协议的灵感来自欧洲火车控制系统（ETCS）（SUBSET，UNISIG，037，Euroradio FIS版本2.3.0； SUBSET，UNISIG，098，RBC-RBC安全通信接口）所采用的通信协议并与之兼容。 ，2007），它旨在成为实现意大利铁路系统各组件之间安全通信的标准层。本文报告了我们在符合欧洲铁路系统安全标准的Protocollo Vitale标准的设计，实施，验证和确认方面的经验。我们首先定义了一个安全计划以及一个验证和确认计划，它们按照安全标准的要求来指导设计，开发，验证和确认活动。严格遵守此类计划的准则，直到工作完成为止，最后以提供安全案例的方式总结所有安全证据。值得注意的是，我们（i）选择了适当的安全机制，（ii）验证了软件设计，（iii）按照代码指标和编码规则实施了该软件，