[SR-Users] Question regarding t_check_trans()

[Daniel-Constantin Mierla]

Hello,

t_precheck_trans() is returning true if a SIP worker process has
received the SIP request and it is handling it at that moment. However,
in case of a retransmission, that can be at the moment when the
transaction was already created for the previous same requests (e.g.,
via t_newtran() or the execution is in a branch_route block). The specs
require that a stateful proxy re-sends the last response in case of a
re-transmission. t_check_trans() is used for that purpose, to see if the
transaction was already created and to what specs require.

If still not clear, I will try to add more details.

Cheers,
Daniel


On 04.08.17 21:45, Joe Baran wrote:
> Probably an elementary question, but we're relatively new at digging
> into the details.  We are trying to understand the following block of
> config code and have a question or two.  Our assumption is the
> t_precheck_trans() function tells us whether another packet has
> arrived already as a retransmission.  However, we're not clear on what
> the t_check_trans() is doing assuming the condition is true.  Any
> direction on this?
>
> Thanks.
>
> route[CHECK_RETRANS]
> {
>   # handle retransmissions
>     if(t_precheck_trans()) {
>         t_check_trans();
>         exit;
>     }
> }
>
>
> Joe Baran
>
>
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-- 
Daniel-Constantin Mierla
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