Enterprise campus network using a three-tier design with Palo Alto PA-3220 firewall protecting DMZ servers and core infrastructure. Traffic flows from ISP Router through the firewall into stacked H3C S6520 core switches, then through L3 aggregation switches to L2 access switches serving PCs and wireless APs across VLANs 10, 20, 30, and 40. The architecture implements redundancy at core and aggregation layers with dual switch stacks and cross-connected uplinks, eliminating single points of failure. This design demonstrates enterprise best practices for network segmentation, high availability, and scalable access layer connectivity. Fork and customize this diagram on Diagrams.so to match your campus topology, VLAN scheme, or switch models.