Virtual Private Cloud (VPC)
Before moving to the cloud you must had thought how your resources will be isolated from other services. Amazon provides VPC (Virtual Private Cloud) allows you to create your own virtual network. The virtual network created by you will closely resemble the on-premise network. The difference between virtual network and on-premise network, it is easy to scale virtual network.
Amazon VPC is different from the on-premise network. You should know how VPC resembles all the features of the on-premise network. A VPC is dedicated to your AWS account. VPC allows you to create subnet within a VPC. You launch your resources in a subnet. When you create an account in AWS, it will provide you a default VPC.
A subnet consists of a specific range of IP address. A subnet allows you to create a network within a VPC. You can have as many subnets you want. A subnet can be divided into two categories. One public subnet that has access to the internet and another is private that that does not have access to the internet.
Typically we launch web server into public subnet and DB server into a private subnet. All the instances in the VPC can communicate using Private IP. One thing is important to notice that if you launch you DB Instance in private subnet then how you are going updating and patching your DB instance. NAT is used to provide outbound connection to the instances launched in private subnet.
You pay only for the resources that you have launched in the VPC. There is no additional charge for creating a VPC. Your VPC IPV$ range must be between /16 netmasks and /28 netmasks. For IPV6 amazon allocate you to an address range of /56 netmasks.