Data Transfer Charges for EC2 Instances in the Same Availability Zone (AZ) - AWS Certified Advanced Networking - Specialty | Amazon

Answer - C.

The below information is given in the AWS Documentation for data transfer for EC2 Instances.

Data transferred "in" to and "out" of Amazon EC2, Amazon RDS, Amazon Redshift, Amazon DynamoDB Accelerator (DAX), and Amazon ElastiCache instances or Elastic Network Interfaces across VPC peering connections in the same AWS region is charged at $0.01/GB.Data transferred "in" to and "out" of Amazon Elastic Load Balancing is priced equivalent to Amazon EC2

Data processed by Amazon Elastic Load Balancing will incur charges in addition to Amazon EC2 data transfer charges.

Using a public or Elastic IPv4 address is charged at $0.01/GB.Using an IPv6 address from a different VPC is charged at $0.01/GB.Amazon EC2, Amazon RDS, Amazon Redshift and Amazon ElastiCache instances or Elastic Network Interfaces in the same Availability Zone is $0.00/GB.Options A, B and D are incorrect since there will be charges which will be incurred when using Public IPs for transferring data.

For more information on demand pricing, please refer to the below URL.

When you transfer data in Amazon Web Services (AWS), you will be charged for the amount of data transferred. The pricing for data transfer varies depending on the source and destination of the traffic, the AWS region, and the type of data transfer.

In this scenario, you have launched two Amazon Elastic Compute Cloud (EC2) instances in separate subnets in the same Availability Zone (AZ) in the us-east-1 region. You are transferring data between these instances using their Public IP addresses. Based on this, the correct answer would be A. There are no data transfer charges for the instances in the same AZ in the same region.

When you transfer data between EC2 instances in the same region using private IP addresses or DNS hostnames, there are no data transfer fees. However, if you transfer data using the Public IP addresses, you will incur data transfer charges at the standard rate of $0.01 per GB.

But in this case, since both instances are in the same AZ, AWS treats the data transfer between them as "in-region data transfer." AWS does not charge for data transfer between EC2 instances in the same AZ, even if you use their Public IP addresses.

It's important to note that if the instances were in different AZs within the same region or in different regions, data transfer charges would apply, based on the type of data transfer and the source and destination regions.

Finally, it's also important to remember that data transfer charges only apply to data that crosses the AWS network boundary. In other words, there is no data transfer charge for traffic that stays within an AWS service or between AWS services in the same region.