Hi, I want to share my findings in making work Freeswitch as SBC when Kamailio is doing serial forking. FS doesnt take any routing decision, it receives the R-URI from Kamailio. After the 1st route failed, I was receiving "482 Request merged" for the 2nd route. That was because the SIP transaction "lives" for 4 seconds in FS after receiving the ACK for a 4xx, 5xx, 6xx reply (only when using UDP). Also, Kamailio takes less than 1 second to try a new route for the same call, thus making FS generates the 482 message. To adapt both to my needs. I set in external.xml the timer T4 to 2500 (default is 4000): <settings> .... <param name="timer-T4" value="2500" /> </settings> In Kamailio, I'm executing the sleep function (from cfgutils module) in the failure_route block: failure_route[2] { ...Get your new ruri only for some reply codes... avp_pushto("$ruri", "$(avp(i:1511))"); append_branch(); t_on_failure("2"); #In case of a new failure this block will be executed again sleep("3"); t_relay(); return; } May be it's not the best solution but it could be helpful for someone else. Best regards, Humberto _________________________________________________________________ Click less, chat more: Messenger on MSN.ca http://go.microsoft.com/?linkid=9677404