私有综合服务网络（PISN）是一种专用网络，用于在组织内部提供通信服务。PISN可以提供多种服务，如语音通信、数据传输和视频会议等。在PISN中，路由限制是一种重要的功能，它可以限制呼叫的路由，以便在特定情况下控制通信。
ISO/IEC 13242:1997标准定义了路由限制类附加网络功能，它是一种用于在PISN中实现路由限制的方法。该标准提供了一个功能模型，描述了路由限制类附加网络功能的各个组成部分及其之间的关系。此外，该标准还定义了信息流，用于在PISN中传输路由限制类附加网络功能所需的信息。
路由限制类附加网络功能可以在PISN中实现多种路由限制策略。例如，可以根据呼叫的源地址、目的地址、呼叫类型或时间等条件来限制呼叫的路由。此外，路由限制类附加网络功能还可以与其他PISN功能集成，以实现更复杂的路由限制策略。
ISO/IEC 13242:1997标准的实现可以提供以下优点：
1. 提高通信安全性：路由限制可以限制呼叫的路由，从而减少未经授权的通信。
2. 提高通信效率：路由限制可以优化通信路由，从而提高通信效率。
3. 提高管理效率：路由限制可以根据组织的需求进行配置，从而提高管理效率。
4. 提高用户体验：路由限制可以根据用户的需求进行配置，从而提高用户体验。
相关标准
ISO/IEC 11579-1:1995 Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Inter-exchange signalling protocol - Circuit-mode basic call control - Part 1: Protocol specification
ISO/IEC 11579-2:1995 Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Inter-exchange signalling protocol - Circuit-mode basic call control - Part 2: Protocol implementation conformance statement (PICS) proforma
ISO/IEC 11579-3:1995 Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Inter-exchange signalling protocol - Circuit-mode basic call control - Part 3: Protocol implementation extra information for testing (PIXIT)
ISO/IEC 11579-4:1995 Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Inter-exchange signalling protocol - Circuit-mode basic call control - Part 4: Protocol implementation extra information for testing (PIXIT) for the support of supplementary services
ISO/IEC 11579-5:1995 Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Inter-exchange signalling protocol - Circuit-mode basic call control - Part 5: Protocol implementation extra information for testing (PIXIT) for the support of call transfer supplementary service