3.6. Cisco Wireless Architectures

💡 First Principle: Wireless deployments face a fundamental choice: let each AP be independent (autonomous), or centralize control in a Wireless LAN Controller (WLC). The trade-off is simplicity vs. scalability. Five autonomous APs are manageable. Five hundred? You need a controller.

What happens without the right architecture: Imagine managing 500 autonomous APs. A new security vulnerability is announced—you need to update every AP individually. That's 500 SSH sessions, 500 configurations, and 500 chances to make a typo. Someone forgets a few APs, and those become attack vectors. With a WLC, you update once, and all 500 APs get the patch. Architecture choice isn't just convenience—it's operational sanity.

Think of it like franchise restaurants. A single restaurant can operate independently—the owner makes all decisions locally. But McDonald's doesn't work that way; corporate headquarters (the controller) pushes standardized menus, procedures, and prices to every location. That's controller-based wireless: one change, applied everywhere instantly.