Re: [Gen-art] Gen-art LC2/Telechat review of draft-ietf-insipid-session-id-24

Elwyn Davies <> Wed, 17 August 2016 17:20 UTC

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To: Ben Campbell <>
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From: Elwyn Davies <>
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Date: Wed, 17 Aug 2016 18:04:23 +0100
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Subject: Re: [Gen-art] Gen-art LC2/Telechat review of draft-ietf-insipid-session-id-24
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Hi, Ben.

Having read Barry's proposed update for RFC 3967,  I would be happy for 
that to become the status quo.  However, I would distinguish between 
truly foundational documents that are produced in tandem with the 
protocol standards or subsequently (as mentioned in Barry's draft) and 
what one might call WG process documents such as requirements documents 
and problem statements. I was going to use the word 'ephemera' to 
describe these latter types, but that is doing them a disservice:  Such 
documents, along with mailing list archives, can provide insight into 
the thought processes that went into the generation of the WG output for 
future reference.  Both the software industry and the standards industry 
is incredibly bad at remembering how decisions were reached - the 
concept of a 'design diary' never seems to have taken hold - with the 
result that we spend an awful lot of time reopening topics that were 
shown to be blind alleys and such like especially after the original 
participants have moved on.

That being said, I think that the 'design diary' category of documents 
probably ought to be archived elsewhere than the RFC series; 
additionally, it is unclear whether applying the RFC review processes 
and resources to an essentially random subset of WG's design thoughts is 
appropriate (that is a random set of WGs rather than a random set of 
thoughts from any one WG - I hope :-) ).  As mentioned below, it is not 
generally known in advance that parts of such documents might end up 
being key references in later standards which can affect both the way in 
which the documents are written (applicable in this case to some extent) 
and the rigour of review  (the WG seems to have done a good job in this 

Up until last month, I think that the foundational documents extension 
would have covered the situation - RFC 6707 broke the mould, and I do 
not consider that foundational covers it.

Back to the current document:  I have reread s3 of RFC 7206 and there 
are some points that need to be sorted out:

- The term 'end-to-end' is given a slightly specialized meaning in RFC 
7206.  This is presumably carried through to the draft under review, but 
the need to refer to the end-to-end definition is not mentioned in the 

- The use of 'session' as a shorthand for the specific meaning of 
'communication session' defined in RFC 7206 ought to be emphasized 
within the draft since the shorthand in RFC 7206 is technically limited 
to the RFC (ok, this is somewhat nitpicking but easy to misinterpret.)

- The last para of s3.1 of RFC 7206 states:

> This definition, along with the constraints imposed by the
>     requirements in this document,....
There is no explicit statement that this standard meets all the 
requirements, so this is difficult to verify and might be problematical 
in future.

Overall, I am of the opinion that in this sort of situation, I'd do a 
copy and paste exercise and tweak the text just a little to fit the 
context more accurately.



On 15/08/2016 21:48, Ben Campbell wrote:
> Hi Elwyn:
> Responsible AD Hat on:
> I'm going to enter a DISCUSS position, to make sure this point gets 
> discussion among the IESG before this progresses. The whole point of 
> the repeated last call was to get feedback on the downref, and this 
> certainly counts :-)
> All hats off:
> As an individual, I still disagree. Specifics inline:
> On 12 Aug 2016, at 18:14, Elwyn Davies wrote:
>> Hi, Ben.
>> AFAICS there is only one really similar case (downref to RFC 6707) 
>> which was approved just last month (based on a problem statement).
> I'm pretty sure there are more than that; the idea that terminology 
> references may need to be normative has come up repeatedly during IESG 
> reviews over the past year or so.
>>  My concern here is that the other framework and requirements 
>> documents are documents that continue to have a relevance (such as 
>> telling a network operator what is necessary to allow deployment of 
>> some IETF-defined technology) rather than being something that 
>> defines what a WG is intending to work on (RFC 6707 and RFC 7206 are 
>> respectively a problem statement and a protocol requirements 
>> statement).  As we know, there has been some considerable discussion 
>> of whether we should really be publishing these documents as RFCs 
>> given that they are snapshots of a discussion position at a point in 
>> time and are only really of academic interest once the working group 
>> has done its work.
> I agree that we should cut down on publication of "requirements", "use 
> case", etc documents that do not have long term archival value. But I 
> don't think there should be as hard of a line as you describe. In 
> particular, sometimes they are valuable for nailing down especially 
> hard-won consensus about requirements. I think that is true for RFC 7206.
> But in any case, I think this is a red herring. RFC 7206 has been 
> published. This discussion isn't going to change that.
>>  Allowing them to be used as normative references further embeds them 
>> into the system.
> I don't see why. Not every action creates a precedent. I do not 
> propose that we add RFC to the downref registry.
>> I would also caution that terminology and such like as defined in 
>> (protocol) requirements and problem statements are generally written 
>> and approved prior to the standards documents in which the are 
>> referenced. Further, I am not totally convinced that the same degree 
>> of rigour is applied to the review of this type of document.  Thus it 
>> is vitally important to ensure that the definitions are still 
>> correct, complete and reflect what is needed for the standard(s): 
>>  The protocols don't always exactly match the requirements - and 
>> there may have been some subtle bending of the meaning of terms over 
>> time!
>> If the downref is to be accepted, then I (and other reviewers) need 
>> to go back and have a harder read of the definitions, unless they 
>> think they already did.
> I believe the working group intent was that the definitions stated in 
> RFC 7206 are the ones used in the protocol.
>>   One consequential question: Is it time for either an update or some 
>> commentary on RFC 3967 as there seems to be a relaxation of the 
>> statements in Section 2?
> RFC 3967 section 2 makes no attempt to be exhaustive. It basically 
> says "there are some reasons to make exceptions. Here are some examples."
> (There actually is an ongoing discussion about relaxing bits of RFC 
> 3967. See draft-leiba-3967upd-downref-00, especially the third 
> paragraph of section 1.)
>> However
>> My view is just that... if the authors, WG, you as AD and the IESG 
>> are happy with the downref and I am in a minority of one (or a very 
>> small number) of the IETF, then there is rough concensus and I'll be 
>> fine with the outcome.  It is only a gen-art revew...
> It's a gen-art review on an IETF last call done _specifically_ for the 
> downref, so I think the outcome is relevant :-)
>> Cheers,Elwyn
>> PSI note that it wouldn't be too late to undo the relaxation.. the 
>> draft referencing RFC 6707 is still with the RFC Editor ;-)
>> /E
> [...]
> Thanks!
> Ben.