Signaling
Click on the red underlined text to get to the source
... authentication protocol and obtaining a static
v6 prefix), someone might be able to spoof the signaling (control
plane security).
...
... Either IKEv1 or IKEv2 provides a secure signaling protocol for
establishing, maintaining, and deleting an IPsec tunnel ...
... to start IKEv2 signaling. A number of ways can be used to provide
the initiator with this information, for example:
...