[SR-Users] Persistent dialog

[Timo Reimann]

Hey Jon,


On 16.08.2011 18:14, Jon Bonilla wrote:
>> Looks pretty much like two dialog entries were created for the same
>> dialog. One of them got cleaned up nicely on call termination while the
>> other one keeps dangling until the dialog timer kicks in (12 hours in
>> your case).
>>
>> Most notably, this situation may happen when spiraling calls without
>> using the spiral detection feature in the dialog module. (A spiral is a
>> scenario where a proxy is processing the same request twice, e.g., to
>> implement call forwardings.) Did you possibly toggle the default spiral
>> detection setting from enabled to disabled?
> 
> No I didn't
> 
> Here's the dialog modparams:
> 
> modparam("dialog","dlg_flag", 9)
> modparam("dialog","profiles_no_value","total ;emergency")
> modparam("dialog","profiles_with_value","peer ; user ; type ; peerout ;
> userout")
> 
> Maybe setting the dialog to TOTAL twice is the problem? I set it before
> proxy
> authentication. I asume that dialog is erased when sending the 407 back
> and a
> new one is created for the second INVITE.

That's what spiral detection is supposed to prevent, i.e., the creation
of multiple structures for the same dialog. However, it only works if
you use the flag to track dialogs, not if you call dlg_manage()
explicitly. I see you have actually configured flag #9 as dialog flag
but just to make sure: Are you using that flag only, not dlg_manage() ?

Even if you did not use dlg_manage(), however, dialogs would likely not
be tracked properly if you started doing so on unauthenticated calls.
The reason is that terminated calls do not get removed until the
associated transaction is deleted. When that second, authenticated
INVITE is handled by the dialog module, it will find a dialog structure
already in the DELETED state (as the dialog ID matches) and refuse
further processing on it.

This may be considered as a shortcoming of the current implementation.
On the other hand, do you actually need to track unauthenticated calls?
They could just be SIP attacks trying to disrupt your infrastructure and
shouldn't be accounted as real calls whatsoever. If you start tracking
dialogs after authentication, things should look better.


Cheers,

--Timo