[SIPForum-discussion] Simultenous UPDATE Handling

[raj kumaradass]

Apologise that i have missed an Ack in the signals flow. Here's the right
one below:

UE-A
  UE-B


      ---------------------INVITE(SDPoff - audio codecs) ------------>

      <--------------------180(Ringing)
---------------------------------------

      <---------------------200 OK(SDPans - audio codecs) ---------
*
      ----------------------- Ack
-------------------------------------------------->*

      ---------------------UPDATE(SDPoff - Video codec) ---------->

      <--------------------UPDATE(SDPoff - Video codec) ------------


I think, now the question would be uncluttered with the above flow. Is it
acceptable to process the UPDATE as a response for the UPDATE req sent? Or
should it be NACKed with error response?


thankS,
...Raj


On Fri, May 28, 2010 at 11:21 PM, Nitin Kapoor <nitinkapoorr at gmail.com>wrote:

> Raj,
>
> Here is what my understanding says.
>
> In this kind of scenarios, additional rules apply to processing an UPDATE
> request with an offer when the gateway has sent a 200 OK response to an
> INVITE request but has not yet received an ACK. The following scenarios
> generate an error response.
>
> 1) If the initial INVITE request contains an offer but does not require
> provisional responses be sent reliably, then the SDP in the 200 OK is
> treated like an answer. If the UAS then receives an UPDATE request before an
> ACK response to the 200 OK, the UAS sends a 500 Server Internal error
> response with a Retry-After header.
>
> 2) If the initial INVITE does not contain an offer and does not require
> provisional responses be sent reliably, then the SDP in the 200 OK is
> treated like an offer. If the UAS then receives an UPDATE request before
> receiving an ACK to the 200 OK, the UAS sends a 491 Request Pending
> response.
>
> Now i might be wrong too. so lets wait for the others opinion.
>
> Thanks,
> Nitin Kapoor
>
>
> On 28 May 2010 16:07, raj kumaradass <rajkumaradass at gmail.com> wrote:
>
>> Greetings,
>>
>> Would like to know how the below scenario be handled, where both the ends
>> of a call send UPDATE msg(inorder to switch from established audio call to
>> video) simultaneously and the timing is more of alike a UPDATE response
>> received for a UPDATE req sent on both the entities.
>>
>>
>> UE-A
>>                                                UE-B
>>
>>       ---------------------INVITE(SDPoff - audio codecs) ------------>
>>
>>       <--------------------180(Ringing)
>> ---------------------------------------
>>
>>       <---------------------200 OK(SDPans - audio codecs) ---------
>>
>>       ---------------------UPDATE(SDPoff - Video codec) ---------->
>>
>>       <--------------------UPDATE(SDPoff - Video codec) ------------
>>
>>
>> Also please suggest if any standards/links which details out on handling
>> similiar scenarios.
>>
>>
>> thankS,
>> ...Raj
>>
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