Which Directory Server Subscriptions do I need if only one master at a time is active?

Issue

We are not fully confident about which licensing model our scenario applies to.
We believe that our architecture matches the typical Master/Replica definition:

“Master and Replica Servers: Definition: 
Master servers are the authoritative source for authorization information 
in an identity management architecture. Replica servers are either 
(a) a passive backup server for a Master server or 
(b) provide distributed authentication for either geographic locality or performance.”

• We want two RH Directory Servers installed at different locations. The second locations provides redundancy in case of a disaster at the primary site. The two LDAP servers are replicated with a Master-Master configuration, but only one Server receives writes requests at any given time. This is achieved by placing the LDAP Servers behind a redundant load balancer. The load balancer talks only to the first LDAP server and virtually promote it at that time to the “current master”, ignoring the second one which makes it to a passive LDAP server.
• In case of problems at the first site or other situations which leaves the current master unavailable to clients, the load balancer will switch over to the second LDAP server by sending all the traffic to this. By then the first (old current master) will be ignored and the second LDAP server will become the “current master”.
• So in our opinion, the second ldap server complies with the definitions of the replica server:
  • a) a passive backup server for a Master server
  • b)… for either geographic locality …
• Probably in future we would like to have the option to change the load balancer configuration to round-robin due to performance issues. Which brings the replication server to:
  • b) ... or performance