Re: New Version Notificationfordraft-ietf-sipping-sip-offeranswer-12

Paul Kyzivat <[email protected]> Thu, 11 Mar 2010 08:45:46 -0500
Newsgroups gmane.ietf.sipping
Message-ID <[email protected]>
Shinji,

I have had a lot of difficulty weaving the various suggestions into the 
overall document. If you would like to see changes like this, can I ask 
a favor of you - could you also please propose the specific text changes 
that are necessary to complete the integration into the document?

	Thanks,
	Paul

OKUMURA Shinji wrote:
> Hi all,
> 
> I study RFC3311 again, so I change my comment.
> 
>> For 4.2 I disagree that 3311 forbids the sending 
>> of an UPDATE while awaiting a prack. (It probably should have been, but 
>> I don't see that it is.)
> 
> I agree. This forbode is not clear.
> In initial INVITE transaction, RFC3311 forbids this UPDATE.
> But for reINVITE, RFC3311 say little.
> 
>> 4.1.  Message Crossing Case Handling
> 
> I revise the table 3.
> 
>      | M1     | M3       | M2      | Action of A         | Action of B                |
>      |(offer1)|(answer1) |(offer2) |                     |                            |
>      +--------+----------+---------+---------------------+----------------------------+
>      | UPDATE | 2xx-UPD  | UPDATE  |                     |                            |
>      |        |          +---------| 491 response for M2 |                            |
>      |        |          | INVITE  |                     |                            |
>      |        |          +---------+---------------------+                            |
>      |        |          | 1xx-INV | should not send     |                            |
>      |        |          +---------+ Mx until M3 in 4a,  |                            |
>      |        |          | 2xx-INV | M1 until My in 4b   |                            |
>      +--------+----------+---------+---------------------+                            |
>      | PRACK  | 2xx-PRA  | UPDATE  |                     |                            |
>      +--------+----------+---------+                     |                            |
>      | 2xx-INV| ACK      | UPDATE  | 491 response for M2 |                            |
>      |        |          +---------+                     |                            |
>      |        |          | INVITE  |                     |                            |
>      +--------+----------+---------+                     +----------------------------+
>      | 1xx-rel| PRACK    | UPDATE  |                     | should not send UPDATE     |
>      +--------+----------+---------+                     | until ACK/PRACK transaction|
>      | INVITE | 1xx-rel  | UPDATE* |                     | is completed.              |
>      |        |----------+---------+                     |                            |
>      |        | 2xx-INV  | UPDATE* |                     | (*:invalid for init-INVITE)|
>      +--------+----------+---------+---------------------+----------------------------+
> 
>> 4.2.  Glare Case Handling
> 
> I propose that the following Figures and Table are added in this section.
> 
>     A                               B
>     |                               |
>     |                re-INV (offer0)|
>     |<------------------------------|
>     |                               |
>     | 1xx-rel (answer0)             |
>     |------------------------------>| --+
>     |                               |   | Acknowledge
>     | offer1(UPD)        offer2(PRA)|   |
>     |============\  /===============| <-+
>     |             \/                |
>     |             /\                |
>     |<===========/  \==============>|
>     |                               |
>     |                      491 (UPD)|
>     |<------------------------------|
>     |                               |
> 
>     A                               B
>     |                               |
>     |re-INV (no offer)              |
>     |------------------------------>| --+
>     |                        offer2 |   |
>     |offer1(UPD)       (1xx-rel/2xx)|   |
>     |============\  /===============| <-+ The 1st reliable response
>     |             \/                |
>     |             /\                |
>     |<===========/  \==============>|
>     |                               |
>     |                      491 (UPD)|
>     |<------------------------------|
>     |                               |
> 
>     A                               B
>     |                               |
>     |offer1(UPD)                    |
>     |===========\                   |
>     |            \                  |
>     |re-INV       \                 |
>     |--------------\--------------->| --+
>     |(no offer)     \        offer2 |   |
>     |                \ (1xx-rel/2xx)|   |
>     |<================\=============| <-+ The 1st reliable response
>     |                  \            |
>     |                   \           |
>     |                    \=========>|
>     |                               |
>     |                      491 (UPD)|
>     |<------------------------------|
>     |                               |
> 
>     | offer1   | offer2   | Action of A                | Action of B                |
>     +----------+----------+----------------------------+----------------------------+
>     |          | reINVITE |                            |                            |
>     | reINVITE +----------+                            |                            |
>     |          | UPDATE   | 491 response for the offer2|                            |
>     +----------+----------+                            |                            |
>     |          | UPDATE   |                            |                            |
>     |          +----------+----------------------------+ 491 response for the offer1|
>     |          | 1xx-rel  | should not send UPDATE     |                            |
>     | UPDATE   +----------+ until ACK/PRACK transaction|                            |
>     |          | 2xx-INV  | is completed               |                            |
>     +          +----------+                            |                            |
>     |          | PRACK  * | (*:invalid for init-INVITE)|                            |
>     +----------+----------+----------------------------+----------------------------+
> 
> Regards,
> Shinji
> 
>> Hi Paul,
>>
>>> I just submitted draft-ietf-sipping-sip-offeranswer-12.txt.
>>>
>>> It addresses comments received re -11 from Okumura Shinji, Brett Tate, 
>>> Gao Yang, and Keith Drage.
>>>
>>> Shinji had a number of comments regarding sections 4.1 and 4.2. I tried 
>>> to fit them in, not literally, but hopefully in spirit.
>> Thank you for your work.
>>
>>>                                                         I had better 
>>> luck with section 4.1. For 4.2 I disagree that 3311 forbids the sending 
>>> of an UPDATE while awaiting a prack. (It probably should have been, but 
>>> I don't see that it is.)
>>    A                               B
>>    |                               |
>>    |                   INV (offer0)|
>>    |<------------------------------|
>>    |                               |
>>    | 1xx-rel (answer0)             |
>>    |------------------------------>| --+
>>    |                               |   | Acknowledge
>>    | offer1(UPD)        offer2(PRA)|   |
>>    |============\  /===============| <-+
>>    |             \/                |
>>    |             /\                |
>>    |<===========/  \==============>|
>>    |                               |
>>
>> [OS]>I think that the offer1 is a protocol violation as PRACK case in 4.1.
>> [OS]>Probably RFC3311(UPDATE) prohibits this operation.
>>
>> RFC3311/Page 5
>> and for the callee:
>>
>>  o  If the UPDATE is being sent before the completion of the INVITE
>>     transaction, and the initial INVITE contained an offer, the
>>     UPDATE cannot be sent with an offer unless the callee has
>>     generated an answer in a reliable provisional response, has
>>     received a PRACK for that reliable provisional response, has
>>     not received any requests (PRACK or UPDATE) with offers that it
>>     has not answered, and has not sent any UPDATE requests
>>     containing offers that have not been answered.
>>
>> At the time of sending the UPDATE, UA A(callee) has NOT received
>> a PRACK for that reliable provisional response. According to the
>> above description, the UPDATE cannot be sent with an offer.
>>
>> Regards,
>> Shinji
>>
>>>                          Ultimately I couldn't figure out how to make 
>>> the comments on that section work. Modulo the parts I agreed with the 
>>> existing text has equivalent meaning, so I left it unchanged.
>>>
>>> Brett pointed out that Retry-After cannot be used with 491. I have 
>>> removed any suggestion that it should be.
>>>
>>> Gao wanted more emphasis on avoiding cases where it might be necessary 
>>> to fail a prack. I have reworded things to make that more explicit and 
>>> removed suggestions to use 491 as a response to prack.
>>>
>>> Keith objected to normative language in the suggestions that Gao made. I 
>>> have avoided using normative language.
>>>
>>> Please review this carefully - its always possible that subtle issues 
>>> could have crept in.
>>>
>>> 	Thanks,
>>> 	Paul
>>>
>>> IETF I-D Submission Tool wrote:
>>>> A new version of I-D, draft-ietf-sipping-sip-offeranswer-12.txt
>>>> has been successfuly submitted by Paul Kyzivat and posted to 
>>>> the IETF repository.
>>>>
>>>> Filename: draft-ietf-sipping-sip-offeranswer
>>>> Revision: 12
>>>> Title: SIP (Session Initiation Protocol) Usage of the Offer/Answer Model
>>>> Creation_date: 2010-03-08
>>>> WG ID: sipping
>>>> Number_of_pages: 22
>>>>
>>>> Abstract:
>>>> The Session Initiation Protocol (SIP) utilizes the offer/answer model
>>>> to establish and update multimedia sessions using the Session
>>>> Description Protocol (SDP).  The description of the offer/answer
>>>> model in SIP is dispersed across multiple RFCs.  This document
>>>> summarizes all the current usages of the offer/answer model in SIP
>>>> communication.
>>>>
>>>> The IETF Secretariat.
> 
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