[Kamailio-Users] Local routing

Hi! I'm planning a new platform based on Kamailio, to replace an existing Cisco-platform. - A total of appr. 2000 ATAs/IP Phones (today appr. 300). - Routing to various providers/gateways via custom made OSP-server. - Two Kamailio-servers on different geographic locations. - Load-balancing/Failover of ATA's by use of DNS-SRV. The main "problem" I see, is how local calls between ATA's registered on each of the Kamailio-servers is routed. How can Kamailio1 route a call to an ATA registered on Kamailio2? What is best in this scenario? 1. If user not found on local Kamailio-server, forward call to next Kamailio-server. 2. Let the Kamailio-servers share the same database (same location-table)? 3. Let the Kamailio-servers copy the REGISTER to the other Kamailio-server(s) so that the other Kamailio-server(s) update their own location-table. I would prefer not to use alternative 1... If alternative 3 is the best, is 't_replicate' the way to do it? What if I add a third Kamailio-server, will that change the recommendation? Martin