[OpenSIPS-Users] reinvite and dialog uniqueness.

johan johan at democon.be
Fri Dec 2 17:35:51 UTC 2022


It would be even better to have somehting without b2b.

On 2/12/2022 17:51, Ovidiu Sas wrote:
>  From has the user that initiated the request.
> For a reINVITE, if the reINVITE is issued by bob, then From has bob URIs.
> Take a look at the examples provided in the Session Initiation
> Protocol (SIP) Basic Call Flow Examples RFC:
> https://datatracker.ietf.org/doc/html/rfc3665
>
> As for the b2b question, take a look at b2b_sed_reply function:
> https://opensips.org/docs/modules/3.3.x/b2b_logic.html#func_b2b_send_reply
> If you need to reply with 200ok to a reINVITE, you need to make sure
> that the SDP in the reINVITE is the same as the initial SDP and send
> back the other party's SDP in 200ok.
>
> -ovidiu
>
> On Fri, Dec 2, 2022 at 11:45 AM johan <johan at democon.be> wrote:
>> I realise that I made an error in my drawing.
>>
>> 1. dialog uniqueness
>>
>>      Alice     calls     Bob
>>
>>              ->INVITE
>>
>>                  call-id: 1
>>
>>                  from: alice at atlanta;tag=1
>>
>>                  to: bob at boston
>>
>>              <- 200
>>
>>                  call-id: 1
>>
>>                   from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>>              -> ACK
>>
>>                  call-id: 1
>>
>>                   from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>> Bob does a session refresh
>>
>>              <- INVITE
>>
>> question in on the from tag and the to tag.
>>
>> should it be
>>
>>              <- INVITE
>>
>>                  callid: 1
>>
>>                   from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>> or
>>
>>              <- INVITE
>>
>>                  call-id: 1
>>
>>                  to: alice at atlanta;tag=1
>>
>>                  from: bob at boston;tag=2
>>
>> or
>>
>>              are both the same dialog (call-id + the 2 tags) ?
>>
>>
>> On 2/12/2022 17:34, Ovidiu Sas wrote:
>>
>> The tag belongs to the SIP endpoint and does not change.
>> Take a look here at an example:
>> https://datatracker.ietf.org/doc/html/rfc3665#section-3.7
>>
>> Regards,
>> Ovidiu Sas
>>
>> On Fri, Dec 2, 2022 at 11:23 AM johan <johan at democon.be> wrote:
>>
>> 1. dialog uniqueness
>>
>>      Alice     calls     Bob
>>
>>              ->INVITE
>>
>>                  call-id: 1
>>
>>                  from: alice at atlanta;tag=1
>>
>>                  to: bob at boston
>>
>>              <- 200
>>
>>                  call-id: 1
>>
>>                   from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>>              -> ACK
>>
>>                  call-id: 1
>>
>>                   from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>> Bob does a session refresh
>>
>>              <- INVITE
>>
>> question in on the from tag and the to tag.
>>
>> should it be
>>
>>              <- INVITE
>>
>>                  callid: 1
>>
>>                   from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>> or
>>
>>              <- INVITE
>>
>>                  call-id: 1
>>
>>                  from: alice at atlanta;tag=1
>>
>>                   to: bob at boston;tag=2
>>
>> or
>>
>>              are both the same dialog (call-id + the 2 tags) ?
>>
>>
>> 2. reinvite
>>
>> Secondly,
>>
>> when opensips is used as b2bua scenario as below
>>
>>
>> A                         opensips                     B
>>
>>          -> invite                     ->invite
>>
>>          <-200                        <- 200
>>
>>          -> ack                        ->ack
>>
>>          ...                                ....
>>
>>                                             <-reinvite for keeeping session alive.
>>
>> Is there a way that I can let respond opensips 200 OK on the reinvite without forwarding the request to A ?
>>
>> so I want
>>
>> A                         opensips                     B
>>
>>          -> invite                     ->invite
>>
>>          <-200                        <- 200
>>
>>          -> ack                        ->ack
>>
>>          ...                                ....
>>
>>                                             <-reinvite for keeeping session alive.
>>
>>                                             ->200
>>
>>
>> instead of
>>
>> A                         opensips                     B
>>
>>          -> invite                     ->invite
>>
>>          <-200                        <- 200
>>
>>          -> ack                        ->ack
>>
>>          ...                                ....
>>
>>                                             <-reinvite for keeeping session alive.
>>
>>          <- reinvite
>>
>>          -> 200                        ->200
>>
>>
>> wkr,
>>
>>
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