2 min lesson
The four moving parts
Use "The four moving parts" to explain each part and the role it plays.
Step 1 of 3
The four moving parts
- Subnet
- A CIDR slice bound to exactly one AZ. Spread each tier across at least 3 AZs so one zone failing costs you a third of capacity, not the service.
- Route table
- What makes a subnet public or private. The default route's target (IGW vs. NAT vs. nothing) is the whole distinction.
- Internet Gateway
- One per VPC. Gives public subnets two-way internet reachability for inbound traffic to load balancers.
- NAT Gateway
- Lets private subnets reach out (pull images, hit APIs) without being reachable from outside. Per-AZ for HA and a real line item on the bill.
Interactive diagram. Tab through its regions; each focused region shows its detail in the panel below.
diagram: stack
Top to bottom: where traffic enters, where it's filtered and what carries it.