802.11 Wireless Standards
IEEE standards evolution — know the key specs
802.11a
1999
5 GHz
54 Mbps
Not compatible
with b/g
with b/g
802.11b
1999
2.4 GHz
11 Mbps
First mass
market Wi-Fi
market Wi-Fi
802.11g
2003
2.4 GHz
54 Mbps
Backward
compat. w/ b
compat. w/ b
802.11n
2009 · Wi-Fi 4
2.4 / 5 GHz
600 Mbps
MIMO
dual-band
dual-band
802.11ac
2013 · Wi-Fi 5
5 GHz only
3.5 Gbps
MU-MIMO
beamforming
beamforming
Exam tip: 802.11ax (Wi-Fi 6, 2.4+5+6 GHz, OFDMA) is the newest but 802.11ac is the most commonly tested. Know that 5 GHz = more channels, less range; 2.4 GHz = longer range, more interference.
WLAN Security — WPA2 vs WPA3
Authentication and encryption standards
WPA2 — IEEE 802.11i
WPA2
EncryptionAES / CCMP
PersonalPSK (passphrase)
Enterprise802.1X + RADIUS
WeaknessPMKID / KRACK attacks
WPA3 — 2018+
WPA3
EncryptionAES-256 / GCMP-256
PersonalSAE (replaces PSK)
Enterprise192-bit security suite
AdvantageForward secrecy, PMKID-safe
Never use: WEP (broken), WPA (TKIP weaknesses), or open authentication for anything sensitive.
AP Deployment Modes
Autonomous vs Controller-Based architecture
AUTONOMOUS AP
Standalone / Fat AP
Each AP configured independently. No central controller. Good for small deployments. Harder to manage at scale — no centralized roaming or RF management.
LIGHTWEIGHT AP (LWAPP / CAPWAP)
Controller-Based / Thin AP
AP offloads management to a WLC (Wireless LAN Controller). Centralized config, roaming, RF management. Uses CAPWAP tunnels (UDP 5246/5247). Enterprise standard.
CLOUD-BASED AP
Cloud-Managed (e.g. Meraki)
APs managed via cloud dashboard. No on-prem controller required. Fast deployment, good for distributed sites.
WLAN Components & Terms
Key concepts for the exam
BSSBasic Service Set — single AP + clients
BSSIDAP's MAC address identifying the BSS
SSIDNetwork name broadcast in beacon frames
ESSExtended Service Set — multiple APs same SSID
IBSSAd-hoc — device-to-device, no AP
DSDistribution System — wired backbone
BeaconAP broadcasts SSID every 100ms (DTIM)
AssociationClient ↔ AP link establishment
RoamingClient moves between APs in same ESS
CAPWAPControl And Provisioning of WAPs protocol
WLC portsUDP 5246 (control), 5247 (data)
2.4 GHz vs 5 GHz Channels
Non-overlapping channel selection is critical
2.4 GHz: Only 3 non-overlapping channels in most regions: 1, 6, 11. All other channels overlap, causing interference.
5 GHz: 24+ non-overlapping 20 MHz channels. Much less interference. 802.11ac / Wi-Fi 5 uses 5 GHz exclusively.
| Band | Non-overlap | Range | Penetration |
|---|---|---|---|
| 2.4 GHz | 3 channels (1,6,11) | Longer | Better (walls) |
| 5 GHz | 24+ channels | Shorter | Worse |
| 6 GHz | 59 channels (Wi-Fi 6E) | Shortest | Worst |
CSMA/CAWireless avoids collisions (can't detect them)
RTS/CTSOptional: reserve medium before transmitting
Wireless Knowledge Drills
Spaced repetition · 60-second timer per question
0
Correct
0
Wrong
0
Streak 🔥
60s
QUESTION 1 · WIRELESS
Packet Tracer Labs
Step-by-step wireless configuration walkthroughs.
Wireless Topology Diagrams
Wireless Cheatsheet
802.11 Standards Quick Reference
802.11a5 GHz · 54 Mbps · 1999
802.11b2.4 GHz · 11 Mbps · 1999
802.11g2.4 GHz · 54 Mbps · 2003
802.11n2.4+5 GHz · 600 Mbps · Wi-Fi 4
802.11ac5 GHz only · 3.5 Gbps · Wi-Fi 5
802.11ax2.4+5+6 GHz · Wi-Fi 6 · OFDMA
Non-overlap 2.4GCh 1, 6, 11
Non-overlap 5G24+ channels
CSMA/CACollision Avoidance (wireless)
CSMA/CDCollision Detection (wired Ethernet)
Security Standards
WEPBroken — never use
WPATKIP — weak, deprecated
WPA2-PersonalPSK + AES/CCMP
WPA2-Enterprise802.1X + RADIUS + AES
WPA3-PersonalSAE (replaces PSK)
WPA3-Enterprise192-bit, forward secrecy
Open authNo security — public hotspots only
802.1X portSupplicant → Authenticator → RADIUS
Autonomous AP Config (IOS)
# Set SSID and security on autonomous AP
AP(config)# interface Dot11Radio0
AP(config-if)# ssid CORP-WIFI
AP(config-if)# no shutdown
AP(config)# dot11 ssid CORP-WIFI
AP(config-ssid)# authentication open
AP(config-ssid)# authentication key-management wpa version 2
AP(config-ssid)# wpa-psk ascii MyP@ssw0rd
AP(config-ssid)# mbssid guest-mode
# Assign SSID to radio interface
AP(config-if)# ssid CORP-WIFI
AP(config-if)# channel 6
# Verify
AP# show dot11 associations
AP# show interfaces Dot11Radio0
Key Wireless Architecture Terms
BSSSingle AP + its clients
ESSMultiple APs, same SSID
IBSSAd-hoc (no AP)
BSSIDAP's MAC address
Autonomous APSelf-contained, no controller
Lightweight APNeeds WLC (CAPWAP)
WLCWireless LAN Controller
CAPWAPUDP 5246 (ctrl) / 5247 (data)
FlexConnectAP can switch locally if WLC down
RoamingClient moves between APs in ESS
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