Amazon VPC enables you to connect your on-premises resources to AWS infrastructure through a virtual private network. This virtual network closely resembles a traditional network that you’d operate in your data center but enables you to leverage the scalable infrastructure in AWS.
Each VPC that you create is logically isolated from other virtual networks in the AWS cloud and is fully customizable. You can select the IP address range, create subnets, configure root tables, set up network gateways, define security settings using security groups, and network access control lists.
Default Amazon VPC
Each Amazon account comes with a default VPC that is pre-configured for you to start using immediately. A VPC can span multiple availability zones in a region. This is the diagram of a default VPC: