Wireless Architectures

Overview

Enterprise Wi-Fi scales through autonomous APs, lightweight APs + WLC (split-MAC), or cloud-managed APs (e.g. Meraki). CCNA expects you to compare these models and explain CAPWAP, AP modes, and WLC deployment options.

802.11 frames (awareness)

802.11 frames differ from Ethernet. Key fields for CCNA:

Field	Role
Frame Control	Type/subtype — management, control, or data
Duration/ID	Medium reservation or association ID
Addresses (up to 4)	DA, SA, RA, TA — presence depends on frame type
Sequence Control	Reassembly and duplicate detection
FCS	Error checking (like Ethernet)

Message types

Type	Examples
Management	Beacon, probe request/response, authentication, association
Control	RTS, CTS, ACK — medium access
Data	Client payload

Association states

Not authenticated, not associated
Authenticated, not associated
Authenticated and associated — required to pass traffic through the AP

Autonomous APs

Self-contained — no WLC. Configured per AP via console, Telnet/SSH, or HTTP/HTTPS GUI.

Pros	Cons
Simple for small sites	No central monitoring
Direct trunk to wired network	VLANs stretch everywhere — large broadcast domains
Low latency path to wired LAN	Does not scale to thousands of APs

Autonomous APs typically connect via trunk when multiple SSIDs/VLANs are needed.

Lightweight APs and split-MAC

Split-MAC divides real-time vs policy functions:

Lightweight AP (real-time)	WLC (policy/coordination)
TX/RX RF, beacons, probes	RF management, channel/power
Encryption/decryption	Security/QoS policies
Packet prioritization	Authentication, roaming, association

APs and WLC authenticate with X.509 certificates before joining.

CAPWAP tunnels

CAPWAP (Control And Provisioning of Wireless Access Points) replaces legacy LWAPP:

Tunnel	UDP port	Traffic
Control	5246	Configuration and management (encrypted by default)
Data	5247	Client traffic to WLC (optional DTLS encryption)

Because client traffic is tunneled to the WLC in centralized mode, AP switch ports are often access ports, not trunks.

Lightweight AP split-MAC — real-time functions stay local; policy moves to the WLC.
Supplementary figure from Panagiss CCNAmd

Split-MAC benefits (awareness)

Centralized channel assignment, transmit power optimization, self-healing coverage, seamless roaming, client load balancing, and consistent security/QoS — without configuring each AP individually.

Lightweight AP modes

Mode	Purpose
Local	Default — serves clients (BSS)
FlexConnect	Local switching if CAPWAP to WLC fails
Sniffer	Capture frames for Wireshark analysis
Monitor	Detect rogue devices; send deauth
Rogue detector	Correlate wired ARP with WLC rogue list
SE-Connect	RF spectrum analysis
Bridge / Mesh	Point-to-point or mesh backhaul
Flex+Bridge	Bridge mode with FlexConnect survivability

Cloud-based APs (Meraki-style)

Hybrid between autonomous and split-MAC: management goes to the cloud dashboard; data typically switches locally to the wired network (unlike CAPWAP central switching).

WLC deployment models

Model	Description	Scale (approx.)
Unified	Hardware appliance WLC	~6000 APs
Cloud-based WLC	VM in private cloud	~3000 APs per VM
Embedded	WLC in a switch	~200 APs
Mobility Express	WLC embedded in an AP	~100 APs

Exam checklist

Compare autonomous vs lightweight AP architecture
Explain CAPWAP control (5246) vs data (5247) tunnels
List split-MAC responsibilities on AP vs WLC
Name FlexConnect purpose (branch survivability)
Identify 802.11 management vs control vs data frames

How the sources were combined