[SR-Users] t_set_fr() different behavior whether transport is udp or tcp

I'm seeing a different behavior of t_set_fr depending on transports. Scenario is that a endpoint has a failover defined in the registrat after 10s (t_set_fr(10000) and handling the locally generated 408 to the failover destination). This works fine when the request and response where delivered over UDP. When the Path is TCP the failover happends after 30s (even when using a different time t_set_fr(20000) so it is not a factor 3 or something like that). Setup: OK, 10s: Orig->UDP->loadbalancer->UDP->registrar->UDP->loadbalancer->TCP->Term Fail, 30s: Orig->UDP->loadbalancer->TCP->registrar->TCP->loadbalancer->TCP->Term Loadbalancer and registrar are kamailio machines (4.3.6). Communication between lb and registrar is based on dispatcher and path modules. 1 sip:registrar:5060;transport=udp 8 0 or via tcp: 1 sip:registrar:5060;transport=tcp 8 0 In the location database of the registrar the difference between the cases is: socket: udp:registrar:5060 or via tcp tcp:registrar:5060 path: <sip:lb@loadbalancer;lr;received=sip:1.2.3.4:5067%3Btransport%3Dtcp> or via tcp <sip:lb@loadbalancer;transport=tcp;lr;received=sip:1.2.3.4:5067%3Btransport%3Dtcp> Looking at debug(=3) nothing happens between the initial INVITE and the local 408 as far as I can see.