Managing public and private subnets

Subnets of AWS are similar to VLAN in DC with a specific range of IPs isolated from an other VLAN/subnet. Each AZ in a region can host multiple subnets, as per the requirement. A subnet is bound by one AZ limit and can't span across multiple AZs. There are two types of subnets; instances created in a public subnet are assigned a public IP and can be accessed from outside the VPC. There is another type of subnet that is called the private subnet. Public IP is not assigned to instance created inside this type of subnet. A default VPC has default subnets associated with it; all default subnets are public subnets.