[Spce-user] rtpengine usage in serial forking

Richard Fuchs rfuchs at sipwise.com
Wed Jan 21 09:17:16 EST 2015

On 01/21/15 09:13, John Nash wrote:
> Yes I can see that even if call-id is same but to tag is different
> rtpengine allocating new port But my issue is end UA receives two
> different ports in two session progress message (One for each forked
> destination). My complete flow is...
> UA Sends Invite to openser
> Openser does rtpengine_offer and forwards to Media Server (IVR) (Port
> 1111 as example sent to Media Server)
> Media Server sends Session Progress to openser and openser does
> rtpengine_answer
> Openser sends Session Progress back to UA (Port 2222)
> At openser media servers sends failure message (After IVR is played) and
> openser sends Invite again to Other destination a gateway (Port 1111sent
> again to gateway too!!)
> When gateway sends session progress and openser does rtpengine_answer
> again it allocates a different port !! 3333 and finally UA receives
> another port in second session progess.
> I understand that To tag is different in second session progress from
> gateway but something seems to be wrong.
> Expected behavior is UA should always receive single port (In both
> session progress) and two Invites (Each to different destinations should
> have different port) isnt it?

Not at all. Remove rtpengine from the scenario and think about who gets
to see which ports. Both invites would contain the same port, but the
replies would contain different ports (in fact different addresses). So
the result is exactly the same.


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