FastConnect and VPN Connect are two key ways for Oracle customers to connect to Oracle Cloud Infrastructure. FastConnect provides a private connection between a customer’s on-premises network and Oracle Cloud Infrastructure, with predictable performance. VPN Connect provides a secure (encrypted) connection over the internet, which might not provide predictable latency and performance.Some enterprises need to encrypt the data flowing through FastConnect to meet security and compliance requirements or to protect sensitive and business-critical information as it moves from on-premises to the cloud.You can achieve this by using the FastConnect and VPN Connect services together. VPN Connect leverages IPSec (IP Security) tunneling technology, which uses industry-standard encryption and cryptographic algorithms. When used with a FastConnect virtual circuit, it provides a secure and dedicated connection with predictable performance.
For full description review Encrypted FastConnect Public Peering white paper.