The figure shows requests going through a load balancer and into both instances I1 and I2. Both instances are now running. Instance I1 is still in Cluster1, and instance I2 is in Cluster2.
Each instance contains an OC4J instance called OC4J_Clustered. Instance I1 runs version 0 of the "App" application, while instance I2 runs version 1 of the same application.
The two OC4J_Clustered instances are still in the same IP multicast replication group, and because both instances are now running, HttpSession replication is taking place.