Hello, On 09/06/2013 02:52 AM, yuanshui lee wrote: If you're having the client register to two different Kamailio servers, you can use the differing 'domains' for them to route the call. If you're having different clients registrar on different registrars, the 'socket' parameter in the 'location' table indicates which registrar the request came into. For instance, if kamailio1 is xxx.xxx.xxx.xxx and kamailio2 is yyy.yyy.yyy.yyy, the 'socket' column for the respective bindings in the 'location' table will contain either udp:xxx.xxx.xxx.xxx:5060 or udp:yyy.yyy.yyy.yyy:5060 So, if you do a registrar lookup on kamailio1 and find the 'socket' to be the other server, you can just route the call over to it laterally. The 'socket' data doesn't get loaded into anywhere accessible by default when you do a lookup(). To get it, you must call reg_fetch_contacts(): http://kamailio.org/docs/modules/4.0.x/modules/registrar.html#idp1933672 Then, the 'socket' will be accessible via $ulc(profile=>socket). See this for more information: http://kamailio.org/docs/modules/4.0.x/modules/registrar.html#idp1950400 -- Alex -- 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/