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

"Joel M. Halpern" <> Fri, 16 December 2016 04:35 UTC

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Subject: Re: Review of draft-mohali-dispatch-cause-for-service-number-12
To: Ben Campbell <>, Joel Halpern <>
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From: "Joel M. Halpern" <>
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Date: Thu, 15 Dec 2016 23:35:33 -0500
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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.


PS: It would seem that WG discussion of that sort is something we would 
like to see in Shepherd writeups.

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.)