2. Terminology (术语)

本文档中的关键词 "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", 以及 "OPTIONAL" 应按照 RFC 2119 [2] 中所述的方式解释, 并表示符合规范的实现所应满足的需求级别.