Re: [sipcore] Session Timers (RFC 4028) for REFER, PUBLISH, MESSAGE not defined

Hi,

I suggest changing the subject of this thread, because it is not specific to session timers.

Regards,

Christer

From: sipcore <sipcore-bounces@ietf.org> on behalf of Samir Srivastava <srivastava_samir=40hush.com@dmarc.ietf.org>
Date: Monday, 11 May 2020 at 18.40
To: Keith Drage <drageke=40ntlworld.com@dmarc.ietf.org>, "sipcore@ietf.org" <sipcore@ietf.org>
Subject: Re: [sipcore] Session Timers (RFC 4028) for REFER, PUBLISH, MESSAGE not defined

Hi,

  Please find my replies Inline below prefixed with SS>>

Thanks
Samir Srivastava
https://samirsrivastava.typepad.com/

On 5/11/2020 at 2:59 AM, "Keith Drage" <drageke=40ntlworld.com@dmarc.ietf.org> wrote:
I dont know whether we reached something we can formally describe as a
decision, but the overall opion was that it should be the text that
should normatively describe what the requirements were for the actions
in respect of inclusion in messages. If these tables were included, they
should be clearly described as informative.
SS>> I am of the opinion that we need header, message etc in the tabulated form. SIP Parser developers cannot be expected to know the minute details of applicability of the messages and headers etc. SIP architect in the vendor comapnies might be required to give the headers and messages in the tabulated form to SIP Parser developers. If we all agree in the tabulated form as SPEC Writers, it will be good service to the community. What are the difficulties considered which made us to deprecate the table format?

Further, the normative text should be adequately worded to encompass the
understanding what happened when new messages were invented - so rather
than specifically listing messages, it should probably talk about
messages that create a dialog, etc.
SS>> PUBLISH RFC https://tools.ietf.org/html/rfc3903
         REFER RFC https://tools.ietf.org/html/rfc3515
          MESSAGE RFC https://tools.ietf.org/html/rfc3428

  They all were invented before RFC 4028.. They were NOT developed after Session Timers. So it is left because of mistake. 4028bis and RFC does not mention PUBLISH, REFER, MESSAGE in the text anywhere. SUBSCRIBE, NOTIFY, PRACK, CANCEL, REGISTER, OPTIONS are only defined in the table nowhere in text. If the added headers (MIN-SE, SEssion-Expires are found in these message should be reject the REQUEST or accept the by following "be lenient what one accepts". Some guideline needs to be specified.
  Developer of new method need to look each header, message etc in their respective RFC. What one can specify for method foo for header foobar in advance?

Keith

On 10/05/2020 17:59, Paul Kyzivat wrote:
> On 5/10/20 9:12 AM, Samir Srivastava wrote:
>> Hi,
>>
>>    The table mentioned in Section 4 in RFC 4028 does not contain
>> entries for REFER, PUBLISH and MESSAGE methods Below is the table
>> from Section 4
>>
>>
>> +---------------+-----+-----+---+---+---+---+---+---+---+---+---+---+
>>     |     Header |where|proxy|ACK|BYE|CAN|INV|OPT|REG|PRA|UPD|SUB|NOT|
>> +---------------+-----+-----+---+---+---+---+---+---+---+---+---+---+
>>     |Session-Expires|  R  | amr | - | - | - | o | - | - | - | o | - |
>> - |
>>     |               |     |     |   |   |   |   |   |   |   | |   |   |
>>     |Session-Expires| 2xx | ar  | - | - | - | o | - | - | - | o | - |
>> - |
>>     |               |     |     |   |   |   |   |   |   |   | |   |   |
>>     |Min-SE         |  R  | amr | - | - | - | o | - | - | - | o | - |
>> - |
>>     |               |     |     |   |   |   |   |   |   |   | |   |   |
>>     |Min-SE         | 422 |     | - | - | - | m | - | - | - | m | - |
>> - |
>> +---------------+-----+-----+---+---+---+---+---+---+---+---+---+---+
>>
>>    They are not applicable for these, but it would have been better
>> if it is said categorically.
>
> IIRC, quite a long time ago it was decided that this table in 3261 was
> a bad idea, because it is essentially a summary of normative language
> in other sections of the document and is necessarily an approximation.
>
> After that, other work that updates and extends 3261 has been
> inconsistent it whether it updates the table or not.
>
> What we should be careful of is that the in progress update to session
> timers is clear, normatively and expositively,  one way or another.
>
>     Thanks,
>     Paul
>
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> sipcore mailing list
> sipcore@ietf.org
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