A network engineer is designing a wireless LAN for a multi-story corporate building and mu… — Cisco CCNA

A network engineer is designing a wireless LAN for a multi-story corporate building and must account for radio frequency (RF) propagation differences between the $2.4\text{ GHz}$ and $5\text{ GHz}$ bands. Which two statements accurately describe the physical characteristics and channel allocations of these frequency bands? (Select two.)

The $2.4\text{ GHz}$ frequency band experiences lower free-space path loss and attenuates less through physical walls, resulting in a larger coverage area per access point.Cevap
The $5\text{ GHz}$ frequency band provides a significantly greater number of non-overlapping $20\text{ MHz}$ channels than the $2.4\text{ GHz}$ band, which helps minimize co-channel interference in high-density enterprise environments.Cevap
C
The $2.4\text{ GHz}$ frequency band supports up to 24 non-overlapping $20\text{ MHz}$ channels, making it preferable for high-density deployment of real-time voice applications.
D
Higher frequency signals in the $5\text{ GHz}$ band penetrate dense building materials such as concrete and brick more effectively than $2.4\text{ GHz}$ signals.
E
The $2.4\text{ GHz}$ spectrum is immune to non-802.11 interference because it operates exclusively within licensed frequency ranges.

Cevap

The correct statements are that the 2.4 GHz band experiences lower free-space path loss and penetrates physical walls better (providing a larger coverage area per AP), and the 5 GHz band provides significantly more non-overlapping 20 MHz channels to mitigate co-channel interference.

The 2.4 GHz band uses longer wavelengths, giving it superior range and obstacle penetration through walls compared to 5 GHz. Additionally, the 5 GHz band provides up to 24 non-overlapping 20 MHz channels in North America (UNII bands), which provides significantly higher capacity and reduces co-channel interference (CCI) compared to the limited 3 non-overlapping channels (1, 6, 11) available in the 2.4 GHz band.

Adım Adım Çözüm

Analyze the RF propagation characteristics of 2.4 GHz versus 5 GHz frequency bands.

Lower frequencies (2.4 GHz) have longer wavelengths, yielding lower free-space loss and superior penetration through physical structures relative to higher frequencies (5 GHz).

RF signal attenuation increases as frequency increases.

Evaluate the channel availability for both frequency bands in enterprise WLAN design.

The 2.4 GHz spectrum has only 3 non-overlapping 20 MHz channels (1, 6, 11), whereas 5 GHz provides up to 24 non-overlapping channels across UNII-1, UNII-2 (DFS), and UNII-3 bands.

Greater channel availability allows high-density access point deployments without co-channel interference (CCI).

Anahtar Kavram

RF Propagation and Channel Allocation Differences (2.4 GHz vs 5 GHz)

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