Free Cisco 300-425 Practice Questions 2026 | Designing Cisco Enterprise Wireless Networks (ENWLSD)

Explanation:

The primary reason 802.11a (5 GHz) connectivity is reduced in X-ray rooms is due to:

Signal attenuation (weakening) caused by lead-lined walls and dense materials used in X-ray room construction.

These materials block or significantly weaken RF signals, including 5 GHz Wi-Fi.

While 2.4 GHz may penetrate slightly better, 5 GHz (802.11a) is more susceptible to attenuation.

Why Other Options Are Incorrect:

A) X-rays create non-Wi-Fi interference – X-rays do not emit RF interference in the 5 GHz band; they are ionizing radiation, not radio waves.

B) X-rays impact UNII-2 channels – X-rays do not affect specific Wi-Fi channels; this is a misunderstanding of RF physics.

C) X-rays cause multipath issues – Multipath is caused by RF reflections, not X-rays.

Reference:

Cisco Wireless LAN Design for Healthcare (RF challenges in radiology rooms).

IEEE 802.11-2016 Standard (RF propagation and attenuation)

. Solution:

Use external antennas or APs outside the room to bypass attenuation.

Deploy Wi-Fi 6 (802.11ax) for better penetration in harsh environments.

Explanation:

To accurately predict the number of APs required for an 802.11ac network supporting ~300 devices, the Demand Settings in Cisco Prime Infrastructure (PI) Planning Tool must be configured. Here’s why:

Demand Settings define:

Client density (number of devices per AP).

Traffic load (bandwidth requirements per device).

Application type (e.g., VoIP, video, data).

Adjusting these ensures the tool calculates AP count based on actual capacity needs, not just coverage.

Why Other Options Are Incorrect:

B) Data Coverage Support Margin – Adjusts coverage thresholds (e.g., -67 dBm), but does not account for client capacity.

C) 802.11n Protocol Support – Legacy setting; irrelevant for 802.11ac capacity planning.

D) Add AP Field – Manually adds APs to the map, but does not auto-calculate based on demand.

Reference:

Cisco Prime Infrastructure Planning Tool User Guide (Capacity Planning Section).

Cisco High-Density Wi-Fi Design Guide (Best Practices for 802.11ac).

Explanation:

To support 4,500 access points (APs) in a multicampus architecture with high availability (HA), the Cisco 8540 Wireless LAN Controller (WLC) is the only viable option. Here’s why:

Cisco 8540 WLC:

Maximum AP capacity: 6,000 APs per controller (supports HA pairs).

Designed for large-scale, multicampus deployments.

Supports high-density wireless data with centralized management.

Why Other Options Are Incorrect:

A) 3504 – Max 200 APs (far below the requirement).

B) 5508 – Max 500 APs (legacy model, insufficient for 4,500 APs).

C) 5520 – Max 1,500 APs (still insufficient).

Reference:

Cisco 8540 WLC Data Sheet (Scalability for large deployments).

Cisco High-Availability Wireless Design Guide (Controller sizing best practices).

Explanation:

To reduce full authentication requests and optimize roaming for CCX wireless phones in a FlexConnect deployment, the engineer should

: Enable CCKM (Cisco Centralized Key Management) on the voice SSID:

CCKM allows fast, secure roaming without full 802.1X re-authentication.

Ideal for voice devices (like CCX phones) to maintain call quality during AP transitions.

Add APs to a FlexConnect group:

Ensures local switching (traffic stays at the branch).

Maintains consistent policies across APs in the group.

Why Other Options Are Incorrect:

B) Enable Aironet IE on the voice SSID and add APs to an AP group – Aironet IE helps with client compatibility but does not optimize roaming like CCKM.

C) Enable Aironet IE on the voice SSID and add APs to a FlexConnect group – Same as above; Aironet IE ≠ roaming optimization.

D) Enable CCKM on the voice SSID and add APs to an AP group – AP groups are for configuration, not local switching (FlexConnect groups are required).

Reference:

Cisco FlexConnect Deployment Guide (CCKM for voice roaming).

Cisco ISE Integration with WLC (PEAP/MSCHAPv2 optimizations).

Explanation:

Signal attenuation varies based on the material’s density and composition. Here’s how these options compare:

Metal door:

Metal is highly reflective and conductive, causing severe signal attenuation (up to 10–20 dB loss).

It acts as a Faraday cage, blocking RF signals almost entirely.

Cinder block wall:

Dense but less attenuating than metal (~6–10 dB loss).

Concrete/masonry materials absorb and scatter signals but don’t block them as effectively as metal.

Glass wall (Non-tinted):

Minimal attenuation (~2–4 dB loss).

Clear glass is mostly transparent to RF signals unless coated/metallized.

Office window (Standard glass):

Similar to glass walls (~2–4 dB loss), unless double-paned/low-emissivity (low-E) coated, which can increase attenuation slightly.

Why Not the Others?

A (Cinder block): Significant but less than metal.

C/D (Glass): Least impactful unless specialized coatings are used.

Reference:

Cisco Wireless LAN Design Guide: Lists metal as the most obstructive material for RF signals.

Explanation:

Cisco mesh networks (e.g., between access points or RAP-to-MAP links) use AES-CCMP (128-bit encryption) for securing the backhaul link. Here’s why:

AES (Correct Answer)

The default and strongest encryption for Cisco mesh backhaul links.

Uses AES-128 in CCMP mode (Counter Mode with Cipher Block Chaining Message Authentication Code Protocol).

Mandated by modern wireless security standards (e.g., 802.11i, WPA2/WPA3).

Hash (Incorrect)
Hashing (e.g., SHA/MD5) is used for integrity checks, not encryption.
Not applicable for securing data in transit.

WEP (Incorrect)
WEP (Wired Equivalent Privacy) is deprecated and easily compromised.
Never used in modern mesh deployments.

3DES (Incorrect)
Triple DES is an older symmetric encryption standard.
Not used in Cisco mesh; AES is preferred for performance and security.

Why Not the Others?

WEP/3DES: Outdated and insecure.

Hash: Used for authentication/integrity, not encryption.

Reference:
Cisco Wireless Mesh Access Points Deployment Guide: Explicitly states AES encryption for backhaul security.

Explanation:

When validating end-to-end network performance (including throughput, latency, and connectivity), an Active survey is required. Here's why:

Active Survey (Correct Answer)

Simulates real client traffic by actively sending/receiving data (e.g., pings, TCP/UDP streams).

Measures actual performance metrics like throughput, latency, packet loss, and retries.

Uses a dedicated test adapter (e.g., Ekahau Sidekick) to generate traffic between the AP and survey device.

Passive Survey (Incorrect)

Only listens to existing AP beacons and client traffic (no traffic generation).

Good for coverage mapping and signal strength but cannot measure performance.

Spectrum Analysis (Incorrect)

Identifies RF interference (e.g., microwaves, Bluetooth) but does not test network performance.

Used for troubleshooting, not validation.

GPS Assisted (Incorrect)

Improves location accuracy during surveys but does not measure performance.

Key Difference:

Passive = "Listening only" (coverage, RSSI, SNR).

Active = "Generates traffic" (throughput, latency, real-world performance).

Reference:

Cisco Wireless Design Best Practices: Active testing is critical for SLA verification.

Explanation:

The scenario requires dual-band coverage but emphasizes mitigating co-channel interference in the 2.4 GHz band, which has only 3 non-overlapping channels (1, 6, 11). Here’s the breakdown:

Disable 2.4 GHz radios on selective APs (Correct Answer)

Since 9 APs are needed for 5 GHz coverage, enabling 2.4 GHz on all APs would cause severe co-channel interference (too many APs competing for 3 channels).

Best practice: Disable 2.4 GHz on some APs (e.g., leave it enabled on only 3-4 APs spaced properly) to reduce overlap while maintaining coverage.

Adjust TPC neighbor threshold to -64 dBm (Incorrect)

TPC (Transmit Power Control) helps manage power levels but doesn’t solve the 2.4 GHz channel scarcity issue.

This setting is more relevant for roaming optimization, not interference mitigation.

Configure static channel/power settings (Incorrect)

Manual tuning can help, but DFS (Dynamic Frequency Selection) and RRM (Radio Resource Management) are preferred in modern deployments.

Static settings won’t resolve the fundamental problem of too many APs on 2.4 GHz.

Deactivate low data rates (Incorrect)

Disabling low data rates (e.g., 1, 2 Mbps) improves airtime efficiency but doesn’t reduce co-channel interference.

Why This Works:

2.4 GHz has only 3 usable channels, so reducing the number of active radios minimizes overlap.

5 GHz has more channels, so all 9 APs can operate without interference.

Reference:

Cisco Wireless LAN Design Best Practices (CVD): Recommends disabling 2.4 GHz on some APs in dense deployments.

Explanation:

The Cisco 5520 WLC supports LAG (Link Aggregation Group), which is the best solution to address both traffic load and redundancy without purchasing a second controller. Here’s why:

LAG (Correct Answer)

Increases bandwidth: Combines two 10-Gb interfaces into a logical 20-Gb trunk, distributing traffic across both links.

Provides redundancy: If one link fails, the other remains active (no single point of failure).

Supported on Cisco 5520 WLC: Officially recommended for scaling AP capacity and improving reliability.

Secondary Port (Incorrect - Option A)

A secondary port (without LAG) is only for failover, not load balancing.

Does not increase bandwidth—only one port is active at a time.

vWLC with SSO (Incorrect - Option C)

SSO (Stateful Switchover) requires two physical controllers (N+1 redundancy).

The scenario explicitly states a second controller is not an option.

vWLC with N+1 (Incorrect - Option D)

N+1 redundancy also requires a backup controller, which violates the given constraint.

Why LAG is the Best Solution:

Scales capacity: Handles 800 APs (500 existing + 300 new) efficiently.

Redundancy: Prevents downtime if one link fails.

No additional hardware cost: Uses existing WLC capabilities.

Reference:

Cisco 5520 WLC Deployment Guide: Recommends LAG for high availability and load balancing.

Cisco Wireless LAN Controller Configuration Best Practices: LAG is the standard for enterprise scalability.

Explanation:

The scenario involves:

AireOS WLCs (guest anchors)

Cisco Catalyst 9800 WLC (foreign controller)

Wi-Fi 6 APs

Inter-controller roaming for guest users

To meet these requirements, the following two design approaches are necessary:

B. Use WLC software versions that support IRCM (Inter-Release Controller Mobility).

IRCM allows seamless roaming between different WLC platforms (AireOS and Catalyst 9800).

Ensures compatibility when mixing AireOS (legacy) and Catalyst 9800 (modern) controllers.

Required for guest anchor/foreign controller setups with different WLC types.

E. Use secure mobility to pair controllers.

Secure Mobility (also called Mobility Groups) is mandatory for inter-controller roaming.

Establishes a secure tunnel between anchor and foreign WLCs for guest traffic handoff.

Without this, guest clients cannot roam between controllers.

Why the Other Options Are Incorrect:

A. Use EoIP for communication between controllers.

EoIP (Ethernet over IP) is not required for AireOS/Catalyst interworking.

IRCM and Secure Mobility handle roaming without EoIP.

C. Use AVC on the anchor WLCs.

AVC (Application Visibility and Control) is for QoS/traffic shaping, not roaming or guest anchor functionality.

D. Use IPv6 across the wireless network.

IPv6 is irrelevant to inter-controller roaming or guest anchor setups.

Key References:

Cisco IRCM Documentation: Confirms support for mixed AireOS/Catalyst 9800 roaming.

Cisco Secure Mobility Design Guide: Required for guest anchor-foreign controller communication.