To effectively deal with the broad and complex requirements of Payment Card Industry (PCI) data security, you need to break the elements apart to provide enhanced clarity. We've designed the PCI X-Ray series to provide actionable information to help Forrester Research clients become PCI-compliant. This document deals with using network segmentation to control the scope of your PCI compliance initiative and provides practical technical guidance to help ensure PCI compliance before your auditor shows up to develop the Report on Compliance (ROC).