Allocate CIDRs - Amazon Virtual Private Cloud

Allocate CIDRs

Follow the steps in this section to allocate a CIDR from an IPAM pool to a resource.


The terms provision and allocate are used throughout this user guide and the IPAM console. Provision is used when you add a CIDR to an IPAM pool. Allocate is used when you associate a CIDR from an IPAM pool with a resource.

The following example shows the hierarchy of the pool structure that you can create with the instructions in this section:

  • IPAM operating in AWS Region 1 and AWS Region 2

    • Private scope

      • Top-level IPAM pool (

        • Regional IPAM pool in AWS Region 2 (

          • Development pool (

            • Allocation - VPC (

In the preceding example, the CIDRs that are used are examples only. They illustrate that each pool within the top-level pool is provisioned with a portion of the top-level CIDR.

You can allocate CIDRs from an IPAM pool in the following ways:

  • Use an AWS service that's integrated with IPAM, such as Amazon VPC, and select the option to use an IPAM pool for the CIDR. IPAM automatically creates the allocation in the pool for you.

  • Manually allocate a CIDR within an IPAM pool to reserve it for later use with an AWS service that's integrated with IPAM, such as Amazon VPC.

This section walks you through both options: how to use the AWS services integrated with IPAM to provision an IPAM pool CIDR, and how to manually reserve IP address space.