[Serdev] [Patch] Ability to check negative reply code in the failure_route

[Maxim Sobolev]

Dan Pascu wrote:
> On Tuesday 08 March 2005 14:07, Maxim Sobolev wrote:
> 
>>I don't think that it really matters. The only thing that matters is
>>that the call has not reached final recepient (which is what 408
>>indicates regardless of its origin). 
> 
> 
> It matters if you want to implement a PSTN fallback mechanism, where you want 
> to send a failed call to a second PSTN gateway.
> In this case you need to know if the call failed because the gateway is dead 
> (in which case you want to try the fallback gateway), or if the call simply 
> did timeout because the destination didn't pick up the phone.

In the case when user have been ringed have not picked up call timely 
the PSTN gateway should use 480 Temporarily Unavailable not 408. Check 
RFC for details. Any abuse of 408 should be reported to the gateway's 
vendor instead.

-Maxim

> 
> In both cases you get a 408, but in the later you don't want to retry the call 
> through the second gateway.
> 
> So it would be nice if SER could generate a different failure code than 408 
> for a gateway/proxy that is dead and doesn't respond at all.
> Or at least there should be a way to distinguish between these cases.
>