Which OCI service should you implement to quickly establish a secure connection between an on-premise data center and OCI?

The most suitable service to establish a secure connection between an on-premise data center and Oracle Cloud Infrastructure (OCI) is FastConnect. FastConnect is designed specifically for creating private, secure, and reliable connections to OCI, offering a more consistent and predictable performance compared to internet-based connections. It provides a direct, dedicated connection that bypasses the public internet, which enhances security and reduces latency.

IPSec VPN is another option for creating secure connections, as it uses the internet to establish a virtual private network. While it offers encryption and security, it may be susceptible to internet congestion and variable latency, which can affect performance. VCN Peering relates to connecting two virtual cloud networks within OCI, which does not apply to on-premise connections. An Internet Gateway, while essential for enabling internet access for resources within a VCN, is not specifically for establishing direct connections between on-premise data centers and OCI.

In scenarios where reliability and throughput are critical, FastConnect is generally preferred to maintain a secure, high-performance link between the on-premise infrastructure and OCI.