电子收费. 自控系统的应用接口定义. 第2部分: 下层通信和连接

[中文适用范围]： 本部分规定了通过任何适用于该应用的通信堆栈和介质（特别是移动通信链路）传递ISO 17575定义的数据元素结构的全部或部分内容的方式。它仅适用于移动通信链路（尽管有线链路，例如后端连接，可以使用相同的方法）。为了建立与服务调用序列的链接以初始化通信通道，接收消息和转发负载是必需的。本部分ISO 17575定义了与具体实现无关的通信服务，表示为一个抽象的应用程序编程接口（API）。该通信接口在前端（FE）系统的首选编程环境中作为API实现。本部分ISO 17575不规范后端（BE）API的说明。以具体术语定义此API超出了本部分ISO 17575的范围。本部分ISO 17575规定了一个抽象API，该API定义了如图3所示的具体API的语义及其协议一致性声明（PICS）表格格式（见附录B）。一个具体的API示例在附录C中给出。当没有区分抽象和具体通信API时，可以使用“通信API”或简称为“API”。 [外文原描述]： ISO 17575-2:2016 defines how to convey all or parts of the data element structure defined in other parts of ISO 17575 over any communication stack and media suitable for this application. It is applicable only to mobile communication links (although wired links, i.e. back office connections, can use the same methodology). To establish a link to a sequence of service calls initializing the communication channel, addressing the reception of the message and forwarding the payload are required. The definition provided in this part of ISO 17575 includes the required communication medium independent services, represented by an abstract application programming interface (API). The communication interface is implemented as an API in the programming environment of choice for the Front End (FE) system. The specification of the Back End (BE) API is outside the scope of this part of ISO 17575. The definition of this API in concrete terms is outside of the scope of this part of ISO 17575. This part of ISO 17575 specifies an abstract API that defines the semantics of the concrete API as illustrated in Figure 3 and its protocol implementation conformance statement (PICS) proforma (see Annex B). An example of a concrete API is presented in Annex C. Where no distinction is made between the abstract and concrete communications APIs, the term "communications API" or just "API" can be used. ISO 17575-2:2016 also provides a detailed specification for the structure of associated API statements, an example on how to implement it and its role in a complex toll cluster such as the EETS (see Annex A to Annex E). Media selection policies, certificate handling and encryption mechanisms are outside of the scope of this part of ISO 17575.