Securing the mGRE tunnel on HUB
To secure the mGRE tunnel with IPsec, perform the following steps on HUB in configuration mode.
Create the profile node.
Set the authentication mode.
Define the preshared secret key. It must match that set on remote systems.
Bind the IPsec configuration to the tunnel.
Specify the ESP configuration to use.
Specify the IKE configuration to use.
Commit the configuration.
View the configuration for the profile.