This failover is done from application by giving the Global database name instead of the instance name at the client side.
This is called CTF (Connect Time Failover) and is not the best choice. I have applied TAF (Transparent Application Failover) which is the proper way to switch to the other node.

To leekwee: I suggest you study OPS in detail before you make decission on switching to it, it is a complicated enviroment and if you have not partitioned your applications, the word lock will become a nightmare :-)