2. Conventions and Definitions (约定与定义)

本文档中的关键词 "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", "OPTIONAL" 应按 BCP 14 [RFC2119] [RFC8174] 中所述解释, 且仅当它们以全大写形式出现时适用.