[Freeswitch-users] FreeSwitch Failover Question

Hi All, I have a question concerning FS failover for high availability. My SIP provider offers the ability to route to a second server if the primary is down. That is simple enough, but what about the phones? The desktop devices are not registered with the back FS server. The only idea I have so far would be to change the DNS addresses to the backup upon failure, but that can take a long time to propagate to the phones. How do other people handle this issue? Thanks, Sean