On Jan 7, 2013, at 4:53 AM, Stewart Bryant <stbryant(_at_)cisco(_dot_)com>
wrote:
Speaking as both a reviewer and an author, I would like
to ground this thread to some form of reality.
Can anyone point to specific cases where absence or over
use of an RFC2119 key word caused an interoperability failure,
or excessive development time?
I'm anecdotally familiar with some early pre-RFC 2543 SIP implementations where
the implementors ignored everything that didn't say MUST and got something that
didn't work. At all. But it was apparently really easy to develop, as the spec
only had a few dozen MUST clauses, and the developers didn't
include-by-reference any of the cited specs, such as SDP.
When we were trying to decide whether to make RFC 3261 (the replacement of RFC
2543) a "draft standards" instead of a "proposed standard", I recall Robert
Sparks and some others attempting to define a "fully interoperable
implementation" test that tabulated all of the RFC 2119 invocations that had
sprouted in FC 3261. They then immediately gave up the idea as impractical, we
recycled at "proposed", and gave up on every making "full". The testing
methodology has greatly improved since then, and it makes lithe use of RFC 2119
language for test definition or construction.
--
Dean