2. Requirements Language (要求语言)

本文档中的关键词"MUST (必须)", "MUST NOT (禁止)", "REQUIRED (必需)", "SHALL (应)", "SHALL NOT (不应)", "SHOULD (应该)", "SHOULD NOT (不应该)", "RECOMMENDED (推荐)", "NOT RECOMMENDED (不推荐)", "MAY (可以)"和"OPTIONAL (可选)"应按照BCP 14 [RFC2119] [RFC8174] 中的描述进行解释,当且仅当它们以全大写形式出现时,如此处所示.