[SIPForum-discussion] reINVITE sent by callee before receiving ACK

[AOEKING]

If the re-INVITE received before the dialog establishment that re-INVITE
will be rejected.

Use SIP UPDATE mechanism to avoid this kind of race conditions

Cheers
Nuwan


On Thu, Dec 19, 2013 at 11:18 PM, tester voip <tester.voip1 at gmail.com>wrote:

> hi,
> as per the rule re-invite is sent by either party when the dialog is
> estabnlished.
> here the caled party sends before receiving ack i.e dialog not established.
>
> although alice wont reject it as it has sent the ack already.
> alice sends 200ok for it.
>
> please corect me if m wrong.
>
>
> On Tue, Dec 17, 2013 at 7:58 PM, Talha Koc <talha.koc at huawei.com> wrote:
>
>>  Hi all,
>>
>>
>>
>> I would like to get your opinions about the race condition shown below.
>>
>> In this scenario, Bob sends a re-INVITE with a new offer before receiving
>> the ACK for the offer 1.
>>
>>
>>
>> Does this violate the offer/answer model? What is the correct behavior
>> for Alice here in this position?
>>
>> Should Alice accept the offer and respond with 200OK with offer2, or
>> should Alice reject it based on the following rule?
>>
>>
>>
>> RFC 6337 2.2:
>>
>> “There may be ONLY ONE offer/answer negotiation in progress for a
>>
>>    single dialog at any point in time.”
>>
>>
>>
>>
>>
>>         Alice                             Bob
>>
>>           |                                |
>>
>>           |        INVITE w/offer1         |
>>
>>           |------------------------------->|
>>
>>           |             180                |
>>
>>           |<-------------------------------|
>>
>>           |                                |
>>
>>           |      200 INVITE w/answer1      |
>>
>>           |<-------------------------------|
>>
>>           |                    reINVITE    |
>>
>>           |   ACK              w/offer2    |
>>
>>           |-------------     --------------|
>>
>>           |              \ /               |
>>
>>           |               X                |
>>
>>           |              / \               |
>>
>>           |<------------     ------------->|
>>
>>           |             ???                |
>>
>>           |------------------------------->|
>>
>>           |                                |
>>
>>
>>
>> *Note: I checked RFC 5407 3.1.4 for a similar scenario, but in that case
>> reINVITE is sent by the caller, not callee.*
>>
>> *Note2: This is my first post in the mailing list.*
>>
>>
>>
>> Regards,
>>
>> Talha
>>
>>
>>
>>
>>
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>>
>
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