title: AWS cross-az traffic
body: <p>i have two instances in two different availability-zones which need to communicate with each other. they are inside vpc private subnets-</p>
  
  <p>a) Will the traffic go through NAT when they talk to each other ?<br>
  b) And what will happen if they are in public subnet and have elastic ip attached ?<br>
  c) What if they are in ec2 classic in two different az ?</p>