[OpenSIPS-Users] Retransmissions with broken UAs

[Brett Nemeroff]

Iñaki,Thanks for clearing that up.. it's quite helpful understanding that..
One question tho. I've seen opensips at times totally ignore a message as
well.. Is there any time that *should* happen?


-Brett


On Tue, May 19, 2009 at 1:39 PM, Iñaki Baz Castillo <ibc at aliax.net> wrote:
>
> El Martes, 19 de Mayo de 2009, Brett Nemeroff escribió:
> > So my question is, what is opensips's behavior with these kinds of
> > transactions.
>
> > I don't understand when opensips decides to retransmit a
> > 200OK (without re-relaying the BYE), versus a 481 Transaction Does not
> > Exist, versus completely ignoring the packet.
>
> This is the correct behaviour of a transaction stateful proxy:
> - Opensips receives the BYE and relays it sucesfully (since it receives
200
> from downstream).
> - Opensips forwards the 200 to the broken UA who "doesn't" understand it
(why?
> no idea).
> - So the broken UA re-sends the BYE.
> - Opensips receives it again and it matches the previous transaction
(which
> remains in memory for 32 seconds). It could occur that the first 200 from
> OpenSIPS to the UA is lost in the network so OpenSIPS MUST be ready to
receive
> a BYE retransmission.
> - After 32 seconds the transactions end so next BYE would be relayed by
> OpenSIPS and would get 481 from the other endpoint.
>
>
> > I was guessing the
> > transaction stays in memory after it's been destroyed just to absorb
> > retransmissions. If that's the case, would i expect to see a 481 once
that
> > timer expires for the same retransmitted BYE?
>
> Yes, but the 481 will be replied by the other endpoint.
>
>
>
> --
> Iñaki Baz Castillo <ibc at aliax.net>
>
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