AWS
Solid = physical (region / AZ)
Dashed = VPC
Dashed = subnet
Region · us-east-1
VPC · regional
10.0.0.0/16
AZ · us-east-1a
subnet
10.0.1.0/24
web-a
10.0.1.5
db-a
10.0.1.9
AZ · us-east-1b
subnet
10.0.2.0/24
web-b
10.0.2.5
✕
one subnet spanning us-east-1a + us-east-1b