Or Availability Domain
One or more isolated, fault-tolerant Oracle data centers that host cloud resources such as instances, volumes, and subnets. A region contains one or more availability domains.
Or Container Network Interface
A Cloud Native Computing Foundation project that consists of a specification and libraries for writing plugins to configure network interfaces in Linux containers, along with a number of supported plugins.
Or Fault Domain
A logical grouping of hardware and infrastructure within an availability domain. Fault domains isolate resources during hardware failure or unexpected software changes.
An Internet Gateway is an optional virtual router you can add to your VCN to enable direct connectivity to the Internet. It supports connections initiated from within the VCN (egress) and connections initiated from the Internet (ingress).
A NAT Gateway gives cloud resources without public IP addresses access to the Internet without exposing those resources to incoming internet connections. A NAT Gateway can be added to a VCN to give instances in a private subnet access to the Internet.
Or Network Security Group
A Network security group (NSG) acts as a virtual firewall for your compute instances and other kinds of resources. An NSG consists of a set of ingress and egress security rules that apply only to a set of VNICs of your choice in a single VCN (for example: all compute instances that act as web servers in the web tier of a multi-tier application in your VCN).
Oracle Cloud Infrastructure is hosted in regions and availability domains. A region is a localized geographic area, and an availability domain is one or more data centers located within a region. A region is composed of one or more availability domains.
A service gateway lets your VCN privately access specific Oracle services without exposing the data to the public Internet. No Internet Gateway or NAT is required to reach those specific services. The resources in the VCN can be in a private subnet and use only private IP addresses. The traffic from the VCN to the Oracle service travels over the Oracle network fabric and never traverses the Internet.
Or Virtual Cloud Network