What is an Amazon VPC? (68/285 technotes for 2015)

Amazon VPC (Virtual Private Cloud) is a 

• virtual network 
  
• Logically isolated area in the AWS cloud
  

Benefits: By launching your instances in VPC

• Assign static IP addresses
  
• Assign multiple IP addresses
• Define Network Interfaces and attach multiple Network Interfaces
• Change Security Group membership - while running
• Control Outbound (egress) / Inbound (ingress) traffic from your instances
• Add an additional layer of access control to your instance in the form of Network Access Control Lists (ACL)
• Run your instance in a single-tenant hardware.
• ELP is associated even when the instance is stopped
• Assign private IP address from a range of private IP addresses

• C1, C2, C3, C4 are EC2-Classic
• C1, C2 - was launched by an account
• C3, C4 - was alunched by a different account
• Can communicate with each other
• Access internet and other services such as S3 directly
• V1, V2 are instances
• V1 & v2 belong to different subnets in the same VPC
• They were launched by the account that owns the VPC
• No other accounts can launch instance in this VPC.
• V1 & v2 can communicate with each other
• V1 & v2 can communicate with C1-C4, S2 and Internet through the Internet Gateway
• 
  

References:

http://amzn.to/1zpcw0Y