Re: Review of draft-mohali-dispatch-cause-for-service-number-12

Cullen Jennings <> Mon, 19 December 2016 17:11 UTC

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Subject: Re: Review of draft-mohali-dispatch-cause-for-service-number-12
From: Cullen Jennings <>
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Date: Mon, 19 Dec 2016 10:11:09 -0700
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To: Joel Halpern <>
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> On Dec 15, 2016, at 10:07 PM, Joel M. Halpern <> wrote:
> At this point I will defer to the relevant ADs.

+1 on that :-)

> As far as I can tell, although the entry was created by an Informational RFC, the registry still claims that it is standards track.
> And since this document is defining behavior, it behaves more like a standards track document than an Informational one.
> But it is up to you folks.  In teh end, all I can do is raise the question, not decide it :-)

So the registry takes PS to change it. And by the current SIP rules, I suspect (not sure) that an update to 4458 would also have to be PS. So really not sure how one gets around this not being PS. 

> Yours,
> Joel
> On 12/15/16 11:51 PM, Ben Campbell wrote:
>>> On Dec 15, 2016, at 10:35 PM, Joel M. Halpern <> wrote:
>>> I see your point about this adding a value to the entry created by RFC 4458.
>>> Is there a reason this can not simply be PS?  The fact that 4458 is Informational does not, as far as I can tell, justify continuing the error.  While this is for a 3GPP usage, it appears to have been reviewed by the Dispatch WG sufficiently to justify PS.
>>> One could argue that there is a down-ref issue,
>>> but the fact that the field is in a standards-track required registry would seem to make that a moot point.
>> Do you think it makes sense to make some new values for “cause” into a proposed standard when “cause” itself is informational?  That seems like a pretty big downref issue, as such issues go. (For the record, I could be convinced to re-run this LC as PS, but I suspect that would lead to objections in the opposite direction.)
>> Right now, the situation is a standards-action registry with a informational entry. That’s clearly broken, but I’m not sure that _this_ draft is the place to fix it.
>> Also, if it makes any difference—even there there was discussion in dispatch, this is not a dispatch work item.
>>> Yours,
>>> Joel
>>> PS: It would seem that WG discussion of that sort is something we would like to see in Shepherd writeups.
>> There’s two paragraphs on the subject in section (1) of the shepherd writeup :-)  (but it wasn’t a working group discussion per se.)
>> Thanks!
>> Ben.
>>> On 12/15/16 11:28 PM, Ben Campbell wrote:
>>>> Hi Joel,
>>>> Thanks for the comments. There has been a fair amount of discussion
>>>> about the status of the draft. The situation is clearly not optimal, and
>>>> I welcome input on how to straighten it out.
>>>> The rational so far has been that this draft updates RFC 4588, which is
>>>> informational. It adds some additional values and related semantics for
>>>> the "cause" parameter from 4588. It does not register new parameters;
>>>> rather it adds itself as a reference in the existing "cause"
>>>> registration. This is mainly a courtesy to readers. (There is no
>>>> sub-registry for "cause" parameter values.) We might could get by
>>>> without that change, since in a perfect world people following the IANA
>>>> reference to 4588 would notice the "Updated by..." tag.
>>>> The gotcha is that RFC 4588 would not be possible as an informational
>>>> today; it would not have standing to register the "cause" parameter. But
>>>> at the time it was published, there was a lack of clarity around the
>>>> "standards action" policy for the SIP URI parameters registry. Making
>>>> the new values from _this_ draft standards track, when the parameter
>>>> itself is not, doesn't seem appropriate. We had some discussion about
>>>> whether we should promote 4588 to PS, but there was not consensus to do
>>>> so when it was published, and I don't see reason to expect that to have
>>>> changed.
>>>> This draft is primarily intended to meet a need in 3GPP, where I
>>>> understand they are effectively already doing this. Would it help to
>>>> more tightly scope this as "Here's something 3GPP is doing..." rather
>>>> than as a general mechanism?
>>>> Thanks!
>>>> Ben.
>>>> On 15 Dec 2016, at 21:57, Joel Halpern wrote:
>>>>> Reviewer: Joel Halpern
>>>>> Review result: Ready with Issues
>>>>> Major:
>>>>>   This document defines a new code for use in SIP, and specifies new
>>>>> behavior both for the code itself and for its use in history-info.  I
>>>>> am thus confused as to how this can be an informational RFC.  It looks
>>>>> like it either Proposed Standard or experimental.  Yes, I see that RFC
>>>>> 4458, which this updates is Informational.  But just because we did it
>>>>> wrong before does not make that behavior correct now.  In addition to
>>>>> my understanding of the roles of different RFCs, I note that RFC 3969
>>>>> and the IANA registry both state that this assignment must be made by
>>>>> a standards track RFC.
>>>>> Minor:
>>>>>  Given our emphasis on IPv6 over IPv4, would it not make sense for
>>>>> the examples to use IPv6 addresses?  (Inspired by the Id-Nits alert.)