[SR-Users] Does forking impact max_inv_lifetime?

[Alex Balashov]

Hi,

In this serial forking-based failover scenario

    UAC --> Proxy --> UAS 1
                      UAS 2
                      ...
                      UAS 3

I've got a requirement to terminate the call and return an error to the 
UAC if there is no final response within 60 seconds.

The usual fr_inv_timer / restart_fr_on_each_reply combination won't do, 
because even when restart_fr_on_each_reply == 0, the timer is still 
restarted on provisional replies of increasing response code value (e.g. 
183 after 180). As the documentation states, fr_inv_timer is a 
branch-level construct anyway, so this approach doesn't make sense here.

That's why I looked into max_inv_lifetime. However, when I set it to 
60000, I still get the same result, but only when there are new branches 
being formed on the proxy -> UAS side. It works fine if there is no 
forking and a single gateway does not provide a final reply within 60 
seconds. So, my sense is that the max_inv_lifetime timeout is reset when 
a new branch is created to UAS 2...UAS N.

Is this accurate?

Thanks,

-- 
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States

Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/