DHCP replication on Windows Server 2012

Hi All,

The DHCP replication a very exciting feature in Windows Server 2012 and R2. But I have some questions.

1. How do the two DHCP servers authenticate with each other for DHCP database replication? Does it has anything to do with the special group "DHCPServer" in the security settings? I heard that the DHCP replication is not only supported while the two DHCP servers are in the same domain/forest, but also in the workgroup mode.
2. What does the "Shared Secret" do? When and where shall I use it?
3. How to check and configure the replication interval?
4. What does "Max Client Lead Time" mean?
5. What does "State Switchover Interval" mean?

Thanks,
高麻雀