public void setIpv4NetmaskLength(Integer ipv4NetmaskLength) {
        this.ipv4NetmaskLength = ipv4NetmaskLength;
    }
<p>
The netmask length of the IPv4 CIDR you would like to associate from an Amazon VPC IP Address Manager (IPAM)
pool. For more information about IPAM, see <a
href="https://docs.aws.amazon.com/vpc/latest/ipam/what-is-it-ipam.html">What is IPAM?</a> in the <i>Amazon VPC
IPAM User Guide</i>.
</p>

@param ipv4NetmaskLength
       The netmask length of the IPv4 CIDR you would like to associate from an Amazon VPC IP Address Manager
       (IPAM) pool. For more information about IPAM, see <a
       href="https://docs.aws.amazon.com/vpc/latest/ipam/what-is-it-ipam.html">What is IPAM?</a> in the <i>Amazon
       VPC IPAM User Guide</i>.
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/AssociateVpcCidrBlockRequest.java