Core: Wireless
In one line Wi-Fi is a half-duplex shared medium - so the real design currency is airtime, not headline data rates. The physics that drive design * Bands: 2.4 GHz (range, few non-overlapping channels - 1/6/11, congested), 5 GHz (more channels, the workhorse), 6 GHz (Wi-Fi
Core: Wireless
Requirement / business driver Choose how APs are controlled and where client data flows - the decision that drives scale, the data path, and WAN behaviour. Options * Autonomous APs - standalone, per-AP config; only for a handful of APs. * Centralized controller (CAPWAP) - APs join an on-prem WLC; central switching tunnels client
Core: Wireless
Requirement / business driver Place WLCs and shape CAPWAP so the data path is efficient and wireless survives failures. Tunnel optimization (the trombone problem) With central switching, all client traffic is tunnelled to the WLC, then back out - even traffic destined locally hairpins/trombones through the controller, adding latency and load.
Core: Wireless
Requirement / business driver Let clients move between APs/controllers without dropping sessions - critical for voice/video and seamless mobility. L2 vs L3 roaming * L2 roaming - client moves between APs in the same subnet/VLAN; keeps its IP, simple. * L3 roaming - client moves to an AP/controller in a different subnet;
Core: Wireless
Requirement / business driver Design the RF so it meets the actual goal - coverage, capacity, voice, or location - which pull in different directions. Coverage vs capacity (the core tension) * Coverage design - fewer APs, larger cells, max range; fine for warehouses/low-density. * Capacity / high-density design - more APs, smaller cells, lower
Core: Wireless
Requirement / business driver Authenticate and encrypt wireless access appropriately for enterprise, personal, and guest use - the air is an open medium. The options * WPA2 - AES-CCMP (avoid legacy TKIP); WPA2-Enterprise uses 802.1X/EAP (AAA and identity - RADIUS, TACACS+, 802.1X), WPA2-Personal uses a pre-shared key. * WPA3