What is SWG:

A Service Gateway (SGW) allows resources in your private subnet to access Oracle services privately, without using the public Internet.

Simple example

Your private OCI server needs to access:

• Object Storage
• Autonomous Database
• Other supported Oracle services

Instead of:

Private Server → NAT Gateway → Internet → Oracle Service

you can use:

Private Server → Service Gateway → Oracle Services Network

Data Flow — From Starting Point

If your private application server needs to upload a backup to OCI Object Storage:

Gateways comparison

NAT Gateway: Private resources → Internet

Service Gateway: Private resources → Oracle Services

Internet Gateway: Public resources ↔ Internet

Note:The server doesn't need a public IP, and the traffic does not need to traverse the public Internet.