The current release of Oracle Golden Gate brings a lot of new and exciting opportunities to use when setting up replication. One of the new things, is that it can be installed along side a 11gR2 database, specifically with a 22.214.171.124 database. With the release of 126.96.36.199 and forward Oracle has introduced a new parameter that must be used with Oracle Golden Gate 12c (188.8.131.52).
This parameter is: ENABLE_GOLDENGATE_REPLICATION
This initialization parameter controls services within the database for Oracle Golden Gate (both the capture and apply processes). This parameter is a dynamic parameter and can be changed while the system is up and running. To enable this parameter, it needs to be set to TRUE. Once turned on, the extracts and replicats that are associated with the database will run when started.
If you forget to enable this parameter when using Oracle Golden Gate, you will be issued the following error:
OGG-02091: Operation not supported because enable_goldengate_replication is not set to true
Once the parameter is enabled (setting it to TRUE), the Golden Gate process in question will start.
For more information on this parameter, go here.