[Kamailio-Users] t_relay("0x02")

[Daniel-Constantin Mierla]

Hello,

On 10/18/08 19:27, Juha Heinanen wrote:
> tm readme on t_relay flag "0x02" says:
>
>   0x02 - do not internally send a negative reply in case of forward
>   failure (due internal error, bad RURI, bad message, etc). When a forward
>   failure occurs, no SIP request is relayed and therefore no negative
>   reply or timeout will show up on the failure_route (if one is set). It
>   applies only when the transaction is created. By default one negative
>   reply is sent. Useful if you want to implement a serial forking in case
>   of failure.
>
> i don't quite understand the statement:
>
>   It applies only when the transaction is created.
>
> what does "It" refer to?
>
> i did some experiments with new lcr implementation and if, for example,
> tcp connection to a gw cannot be established, then t_relay without
> "0x02" flag generates 477 reply to caller and, indeed, failure route is
> not executed.  
>
> so i need test if t_relay("0x02") failed due to "send failed" and handle
> selection of next gw in the same route block where t_relay("0x02") was
> called.  this is inconvenient, because there already exists a failure
> route block that does all that and now its code needs to be at least
> partially duplicated.
>
> or am i missing something and it is somehow possible to get a failure
> route block executed also on this kind of internally generated negative
> reply
Not now, but we can have it as feature request and see what can be done 
by next release. It will look indeed more coherent.

Now, an workaround could be to move content of failure_route in a route, 
call that route from failure route and after the relay fails. I think 
there should be introduced a new PV that can tell what is the type of 
root route block (request route, failure route, reply route), so one can 
take decisions based on that in script.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
http://www.asipto.com