Conformance Terms to Indicate Requirement Levels
Peter Saint-Andre · 2011
In many protocol specifications and related documents, special conformance terms (e.g., the uppercase words MUST, SHOULD, and MAY) are often used to signify requirement levels. This document defines these conformance terms and describes how they are to be interpreted in documents produced within the Internet Standards Process. If approved, this document obsoletes RFC 2119 and changes its status to Historic.