[OpenSIPS-Users] reinvite and dialog uniqueness.

Ovidiu Sas osas at voipembedded.com
Fri Dec 2 16:51:38 UTC 2022


>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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