Cisco CCNA WLAN Architectures and Concepts 5 — Questions and Answers
Question 1: What distinguishes WPA3-Personal from WPA2-Personal in terms of key exchange?
- WPA3 uses a 4-way handshake with a pre-shared key
- WPA3 uses Simultaneous Authentication of Equals (SAE) instead of PSK (Correct answer)
- WPA3 replaces AES with ChaCha20 encryption
- WPA3 requires a RADIUS server for authentication
Correct answer: WPA3 uses Simultaneous Authentication of Equals (SAE) instead of PSK
WPA3-Personal uses SAE (Simultaneous Authentication of Equals), also known as Dragonfly, which provides forward secrecy and resistance to offline dictionary attacks.
Question 2: A Cisco AP is configured in 'sniffer mode.' What is the primary function of this mode?
- Serving clients while simultaneously scanning for rogues
- Capturing all 802.11 traffic on a channel and forwarding it to a packet analyzer like Wireshark (Correct answer)
- Providing a wireless bridge between two wired segments
- Acting as a backup AP when the primary AP fails
Correct answer: Capturing all 802.11 traffic on a channel and forwarding it to a packet analyzer like Wireshark
Sniffer mode causes the AP to capture raw 802.11 frames on a specified channel and forward them to a remote packet capture tool such as Wireshark for analysis.
Question 3: Which mechanism does 802.11 use to avoid collisions in the wireless medium since CSMA/CD cannot be used?
- CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) (Correct answer)
- Token passing between associated clients
- Time Division Multiple Access (TDMA)
- Polling by the AP to grant transmission rights
Correct answer: CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)
Wi-Fi uses CSMA/CA where devices sense the medium and use random backoff timers to avoid collisions, since collisions cannot be detected in wireless environments.
Question 4: In a Cisco WLC high availability (HA) pair, what is the role of the 'secondary' WLC when the primary is active?
- The secondary actively serves half the APs to distribute load
- The secondary maintains a warm standby, ready to take over all APs if the primary fails (Correct answer)
- The secondary handles only guest WLAN traffic
- The secondary operates independently as a separate cluster member
Correct answer: The secondary maintains a warm standby, ready to take over all APs if the primary fails
In Cisco WLC HA, the secondary controller stays in a warm standby state, synchronizing state with the primary and ready to assume all AP connections upon primary failure.
Question 5: What is a 'hidden node problem' in wireless networking, and what mechanism addresses it?
- A node that is hidden from the WLC; addressed by increasing transmit power
- Two clients that cannot hear each other but both transmit to the same AP causing collisions; addressed by RTS/CTS (Correct answer)
- An AP that is not visible in the WLC dashboard; addressed by CAPWAP rediscovery
- A client that hides its MAC address; addressed by MAC filtering
Correct answer: Two clients that cannot hear each other but both transmit to the same AP causing collisions; addressed by RTS/CTS
The hidden node problem occurs when two clients can't detect each other's transmissions but share the same AP; RTS/CTS handshaking reserves the medium to prevent collisions.
Question 6: Which statement about the 802.11ax (Wi-Fi 6) standard is correct?
- It operates only in the 6 GHz band
- It introduces OFDMA to improve efficiency in dense, multi-client environments (Correct answer)
- It reduces maximum channel width to 80 MHz for better range
- It replaces MIMO with beamforming as the only spatial multiplexing method
Correct answer: It introduces OFDMA to improve efficiency in dense, multi-client environments
802.11ax (Wi-Fi 6) introduces OFDMA (Orthogonal Frequency Division Multiple Access) allowing simultaneous transmission to multiple clients, greatly improving efficiency in dense deployments.
Question 7: When deploying a Cisco WLC, which port type connects the WLC to the switched network and carries multiple VLANs for different WLANs?
- Access port configured for the management VLAN only
- Trunk port carrying all required VLANs for management and dynamic interfaces (Correct answer)
- Routed Layer 3 port with a separate IP per WLAN
- EtherChannel with individual VLANs on each member link
Correct answer: Trunk port carrying all required VLANs for management and dynamic interfaces
The WLC distribution system port is connected to a switch trunk port that carries all required VLANs, allowing each WLAN/SSID to map to its respective VLAN.
Cisco CCNA WLAN Architectures and Concepts 5
What distinguishes WPA3-Personal from WPA2-Personal in terms of key exchange?