Additional Key words to Indicate Requirement Levels

Document Type Expired Internet-Draft (individual)
Author Paul Hoffman 
Last updated 2008-01-15
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Some document authors want to express requirement levels using the traditional definitions of "MUST" and "SHOULD" from RFC 2119, but also want to express that there is an expectation that later versions of the document may change those requirements. For example, they may want to express "this SHOULD be implemented now, but we expect that this will become a MUST requirement in a future update to this standard". This document defines three new keywords, "MUST-", "SHOULD+", and "SHOULD-" to facilitate such definitions.


Paul Hoffman (

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