In WLANs utilizing 802.1X authentication, client roaming involves re-authentication processes, which can introduce latency. To enhance roaming efficiency, key caching mechanisms are employed:
Pairwise Master Key (PMK) Caching:Allows a client to reuse a previously established PMK with an AP, reducing authentication time during roaming.
Opportunistic Key Caching (OKC):Enables clients to use the same PMK across multiple APs within the same mobility domain, facilitating faster transitions.
Fast BSS Transition (802.11r):Introduces protocols for quick and secure handoffs between APs.
Implementing these key caching protocols significantly improves client roaming performance in MCA networks.
Reference: CWDP-305 Official Study and Reference Guide, Chapter on Wireless Design Process

When calculating the total noise figure of cascaded components, Friis' formula is used:
F_total = F1 + (F2 - 1)/G1 + (F3 - 1)/(G1 × G2) + ...
Where:
F_totalis the total noise factor (linear, not in dB).
F1, F2, ...are the noise factors of the individual stages.
G1, G2, ...are the gains of the preceding stages (linear, not in dB).
In this scenario, the amplifier has a gain of 0 dB, which corresponds to a linear gain of 1. A noise figure of 10 dB corresponds to a noise factor of 10. Assuming the cable and filter have negligible noise contributions or are passive components with minimal loss, their impact on the total noise figure is minimal.
Applying Friis' formula:
F_total = 10 + (1 - 1)/1 = 10
Converting back to dB:
NF_total = 10 × log10(10) = 10 dB
Reference: CWDP-305 Official Study and Reference Guide, Chapter on ProtocolandSpectrum Analysis

Comprehensive and Detailed Explanation:
When transitioning from a centralized to a distributed data forwarding model in a WLAN architecture, it's important to consider the capabilities of the existing APs. Some APs designed specifically for centralized forwarding may lack the necessary hardware or firmware support to operate effectively in a distributed forwarding mode. This can lead to compatibility issues and may require hardware upgrades or replacements to ensure proper functionality in the new architecture.
Reference: CWDP-305 Official Study Guide, Chapter on Infrastructure Design

Dynamic Channel Assignment (DCA) algorithms optimize the RF environment by automatically selecting channel assignments based on factors like interference, noise, and utilization. However, DCA requires tuning of algorithm parameters to align with the specific design and site requirements.
From CWDP-305:
"Dynamic channel assignment and transmit power control must be configured according to the design goals and validated after deployment. Default settings may not produce optimal results in all environments." Simply relying on default settings without adjustment can lead to poor RF behavior.
- Reference: CWDP-305 Official Study and Reference Guide, Chapter on Wireless Design Process

Comprehensive and Detailed Explanation:
An incorrect Frame Check Sequence (FCS) indicates that the frame was corrupted during transmission. This corruption can be due to various factors, but in the context of a WLAN, common causes include multipath interference and excessive collisions. Multipath occurs when RF signals reflect off surfaces and arrive at the receiver at different times, causing interference. Excessive collisions can happen in environments with high device density or overlapping coverage areas, leading to degraded performance.