On-premises SAP and POS integration architecture with segmented VLANs, perimeter security, and middleware-driven data synchronization. Store staff access POS terminals through a DMZ-protected network, while SAP admins manage ERP systems in an isolated VLAN 20, with both systems communicating via REST APIs and message brokers. The architecture enforces network segmentation using internal firewalls, reverse proxies, and WAF protection to minimize blast radius and ensure compliance with enterprise security policies. Fork this diagram on Diagrams.so to customize firewall rules, add disaster recovery paths, or integrate additional middleware components for your retail environment. This pattern is ideal for large retailers requiring strict separation of payment systems from financial ERP while maintaining real-time inventory and sales synchronization.