Restrict database connections during switchover

Hi all,

We have 2-node RAC as primary and single node physical standby database.

We are going to perform dataguard switchover in our environment.

Before starting the activity we need to restrict the application connections i.e., client connections to database for smooth role switch. Please suggest us possible ways to do this.

Post switchover we need to allow connections.

Thanks,

Adepu Vikram.