Re: [homenet] Kathleen Moriarty's Discuss on draft-ietf-homenet-hncp-09: (with DISCUSS)

Ted Lemon <> Thu, 19 November 2015 17:12 UTC

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From: Ted Lemon <>
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Date: Thu, 19 Nov 2015 17:12:19 +0000
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Subject: Re: [homenet] Kathleen Moriarty's Discuss on draft-ietf-homenet-hncp-09: (with DISCUSS)
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Thursday, Nov 19, 2015 1:49 AM Brian E Carpenter wrote:
>> Just to clarify, mandatory to implement doesn't mean you have to write the code.   It means the functionality has to be present in the deployed implementation so that two communicating partners can be configured to use it.   
> Um, where is that defined? Is there a BCP that says that?

It's not codified into law, but what else could it mean?   Why would we specify something as mandatory to implement if an expression of that implementation in running code did not actually contain the implementation?

> I don't think a protocol spec can say that feature X cannot be ifdeffed.
> It can say that a protocol must be capable of X and that implementations
> must therefore be capable of X. But if you tell implementors that they can't
> ifdef unused stuff when building images for highly constrained nodes, I
> don't think they will take you seriously.

The protocol spec would just say MUST implement.   If the implementor wants to conditionalize the compilation of the code, we can't stop them from doing that, but then they don't have an implementation of the specification, and they shouldn't say "supports RFC XXX".   "supports RFC XXX" means that anything that is specified in the RFC is asserted to be functional in the implementation.

They can perfectly well say "supports a subset of RFC XXX," and I can't imagine that anybody would object to that.

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