1.4. Conventions Used in This Document (本文档中使用的约定)

本文档中的关键词 "必须 (MUST)", "不得 (MUST NOT)", "要求 (REQUIRED)", "应当 (SHALL)", "不应当 (SHALL NOT)", "应该 (SHOULD)", "不应该 (SHOULD NOT)", "推荐 (RECOMMENDED)", "可以 (MAY)", 以及 "可选 (OPTIONAL)" 应按照 [RFC2119] 中的描述解释。