OCI Architect Associate Certification Study Notes

Networking is the heaviest domain. Questions center on building a VCN with the right subnets, routing, and security model for a given connectivity requirement.

Subnets and Routing

• A VCN is a regional private network defined by one or more CIDR blocks
• Regional subnets span all availability domains in the region
• AD-specific subnets are pinned to a single availability domain
• A public subnet needs a route to an internet gateway and instances need public IPs
• A private subnet has no route to an internet gateway
• Route rules are evaluated by longest prefix match, not by rule order
• A subnet uses one route table, but a route table can serve many subnets

• VCN DNS gives instances resolvable names and supports internet or custom resolvers
• Flow logs capture connection-level traffic for auditing and troubleshooting
• Site-to-Site VPN uses IPSec over the internet; FastConnect is a private dedicated link
• Load balancers are public or private and can be flexible in bandwidth

Exam Focus Areas

• Public subnets need an internet gateway route; private subnets use a NAT gateway for egress
• Use NSGs for per-instance security and security lists for subnet-wide baseline rules
• Same-region VCN peering uses LPG; cross-region peering uses DRG and RPC
• Route selection is longest prefix match — never rely on rule ordering