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

[Keith Drage <[e-mail]>]

Most header fields are included for a specific purpose entirely 
unassociated with what mesage it is in.

i.e. things like

-    included because this message creates a dialog

-    included because this message ends a dialog

-    included becases this message is the request in a transaction

-    included because this message responds to a transaction

-    included because I can include it in any request

etc.

Those concepts have existed since RFC 3261.

The exceptions tend to be header fields that are defined along with a 
MESSAGE to carry them, i.e. in the same RFC.

I am not suggesting the definers of new messages should not give due 
consideration, only that in most cases they will not need to add any 
extra requirements to their new RFC, because all the considerations 
could already be in the header field defining RFC.


Keith

P.S. I would note that you cannot go on the date of publication - many 
RFCs take years to get through publication request to published while 
others proceed quicker.



On 11/05/2020 16:39, Samir Srivastava wrote:
> 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=[e-mail]> 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
>     >
>     > _______________________________________________
>     > sipcore mailing list
>     > [e-mail]
>     > https://www.ietf.org/mailman/listinfo/sipcore
>
>     _______________________________________________
>     sipcore mailing list
>     [e-mail]
>     https://www.ietf.org/mailman/listinfo/sipcore
>
>
> _______________________________________________
> sipcore mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/sipcore