What is an aws subnet?

[amurleopard]

See: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Subnets.html for full details.

A VPC is a virtual network. A subnet defines a subset of the network.

You can have public IP addresses or you can have private IP addresses, depending on whether you services are going to communicate with the network or not.

A subnet in AWS cannot span availability zones.

Subnets within a VPC can be default route traffic to one another.

The first 4 IP addresses in a CIDR block and the last IP address cannot be used.

From: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Subnets.html

Subnet must be associated with a route table for outgoing traffic, there is also the main route table for the VPC, when you create a new subnet, a route is automatically added to the main route table.