Hello,
I'm trying to address a problem where sometimes our upstream providers have 
slow call setup times.  We use drouting with multiple providers for each route 
to handle failover in the event of an outage but in this case, we get a 100 
Trying but sometimes a 18[03] response takes 4-5 seconds or we never get it 
because the caller cancels the request.  What would be a "safe" amount of time 
to allow a PSTN gateway to reply with a 180/183?  What I'm trying to avoid is a 
scenario where the PSTN legitimately takes a long time to setup (i.e. an 
international call to some cell phone providers) and we needlessly failover 
which will actually increase the post dial delay for the user.

My thought is this for example:

route[PSTN] {
    t_set_fr(1000);   # set fr timer to 1 second so we failover quickly if no 
provisional response
    t_on_reply("PSTN_REPLY");

   # Routing logic
}

onreply_route[PSTN_REPLY] {
    if (status=~"1[0-9][0-9]") {
         t_set_fr(4000);    # set fr timer to 4 seconds
    }

    if (status=~"18[03]") {
         t_reset_fr();    # reset timer if we get a 180 or 183
    }

}

Also, if we failover because of slow call setup for a particular route, I'd 
like to temporarily avoid that gateway for that route (but only that route).

I'm curious if anyone has any pointers or how they solved this.

Thanks,
Spencer



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