提供安全服务和相关机制（可通过参考模型确保）的一般说明，以及参考模型中可提供服务和机制的位置的一般说明。扩展了ISO 7498的应用范围，以涵盖开放系统之间的安全通信。增加了ISO 7498中包含的概念和原则，但未对其进行修改。没有实现规范，也不是评估实际实现一致性的基础。

Provides a general description of security services and related mechanisms, which can be ensured by the Reference Model, and of the positions within the Reference Model where the services and mechanisms may be provided. Extends the field of application of ISO 7498 to cover secure communications between open systems. Adds to the concepts and principles included in ISO 7498 but does not modify them. Is no implementation specification, nor a basis for assessing the conformance of actual implementations.