“Layer 3 access” or “routed access” is not a specific vendor feature — it's a design pattern: Each access switch (or stack) becomes a Layer 3 device, not just a Layer 2 island. End devices are still in VLANs, but the default gateway SVI lives on the access switch, not. When planning an enterprise access network, one of the most common dilemmas is whether to deploy Layer 2 (L2) or Layer 3 (L3) switches. The access layer plays a critical role in connecting end devices—such as computers, printers, IP phones, and wireless access points—to the rest of the enterprise. This chapter explains configuring Layer 3 wireless controller deployments on Cisco Catalyst 9800 series, covering L3 access setup, OSPF and PIM multicast integration, DHCP/NAT with VRF, and verification commands. enables client subnet segmentation, overlapping IP support, and a scalable network. The goal is not to declare “Layer 2 bad, Layer 3 good,” but to give you a practical mental model: When should I stop stretching VLANs and start routing closer to the edge? 1. These networks are designed with three tiers that facilitate strategic installation, management, and maintenance, and so on. The strategic design of a hierarchy network may comprise more than three layers. In this lesson, we examine the network devices that operate at Layer 3 of the OSI model. It plays a critical role in modern networks by performing high-speed packet forwarding while also making routing decisions at Layer 3.