Also referred to as “segmentation” or “isolation.” Network segmentation isolates system components that store, process, or transmit cardholder data from systems that do not. Adequate network segmentation may reduce the scope of the cardholder data environment and thus reduce the scope of the PCI DSS assessment. See the Network Segmentation section in the PCI DSS Requirements and Security Assessment Procedures for guidance on using network segmentation. Network segmentation is not a PCI DSS requirement.