[OpenSIPS-Devel] RFC 4320 and 4321?

[Bogdan-Andrei Iancu]

Hi Inaki,

Iñaki Baz Castillo wrote:
> Hi, RFC 4320 handles some issues about non INVITE transactions described in 
> RFC 4321. For example:
>
> - A proxy should NOT generate a 408 during parallel forking in a branch 
> doesn't respond because when this 408 is sent the UAC client transaction has 
> been already destroyed by it own timer.
> Please, take a look to RFC 4321 (specially figure 3).
>
> - A transaction-stateful SIP proxy MUST NOT send any response to a
> non-INVITE request unless it has a matching server transaction that
> is not in the Terminated state.  As a consequence, this proxy will
> not forward any "late" non-INVITE responses. (This avoids late replies that 
> will not match UAC client transaction).
>
>   
The whole story from RFC 4321 has as ground the fact that all SIP 
entities have the same T1 value. But RFC3261 gives recommendation about 
the value, so you can have different values on different SIP entities - 
in such case, the race condition case is not valid anymore.
> I've tested it and OpenSIPS doesn't implement this RFC. If during parallel 
> forking a branch doesn't respond then OpenSIPS replies 408 that is useless in 
> most cases.
>   
you mean opensips replies with 408 to the upstream UAC (transaction 
conpletion) or internally on the given branch?

Regards,
Bogdan