amazon aws - regional data transfer - in/out/between EC2 Avail Zones

can anyone say what this charge item is from the account activity?

$0.010 per GB - regional data transfer - in/out/between EC2 Avail Zones or when using public/elastic IP addresses or ELB

i launched ONE and ONLY ONE micro instance of amazon ec2 and am wondering what this charge is exactly? it's very small, but still i do not understand it.

thnx :)

Your server is talking to itself using it's external IP address. You can keep this to a minimum by configuring your services to work with the internal IP if possible. Anything you do using DNS lookups should use a CNAME record to (or directly reference) the name given by amazon. This way internal lookups will return the internal address and external lookups the external address.

It is not uncommon for linux services to talk to each other even on the same machine using networking layers. Usually this is short circuited by the localhost interface, but not always.

Edit: For further reading see these articles on why CNAME is better and internal elastic ips.

In addition there are so called Availability zones. You choose them when creating a new EC2 Instance. You can think of it as a different datacenters. So if some instance in Virginia is accessing another instance in Europe then you will be charged.

List of Availability zones available in Amazon (taken from EC2 description page):

• US – N. Virginia
• US – N. California
• EU – Ireland
• APAC – Singapore