Pass the CWNP CWDP Wi-Fi Design CWDP-305 Questions and answers with CertsForce

USB 3.0 interfaces are known to generate RF interference in the 2.4 GHz band due to the high-frequency noise emitted by the differential signaling in USB 3.0 cables and ports. This interference can reduce SNR, especially for devices located close to the USB port.

From CWDP-305:

“USB 3.0 cables and ports can emit broadband noise in the 2.4 GHz band, negatively impacting receive sensitivity and SNR. This can distort measurements during protocol analysis or performance testing.”

— Reference: CWDP-305 Official Study and Reference Guide, Chapter on ProtocolandSpectrum Analysis

The Friis transmission equation is used to calculate the free-space path loss (FSPL) between two antennas.It considers the distance (d) between the antennas and the frequency (f) of the transmitted signal.This equation is fundamental in wireless design to estimate the loss of signal strength over a line-of-sight path, aiding in link budget calculations and ensuring reliable communication.

In public WLAN environments, security and privacy are paramount. To prevent clients from communicating directly with each other, many WLANs implement peer-to-peer blocking (also known as client isolation). This feature ensures that each client can communicate with the internet but not with other clients on the same network, thereby enhancing security.

The CWDP-305 Official Study and Reference Guide discusses this feature:

"Client isolation prevents wireless clients from communicating directly with each other, which is especially important in public or guest networks to protect user privacy and security."

Therefore, the inability to detect other devices on the subnet is likely due to peer-to-peer blocking being enabled on the WLAN infrastructure.

When designing a WLAN infrastructure, it's essential to calculate the Power over Ethernet (PoE) budget accurately to ensure all Access Points (APs) receive sufficient power. IEEE 802.3at, also known as PoE+, provides up to 30 watts of power per port. Therefore, for 6 APs:

6 APs × 30 W = 180 W

This calculation assumes that each AP requires the full 30 W provided by IEEE 802.3at and that there are no additional power losses or overheads. It's always a good practice to include a buffer in real-world scenarios to account for power losses in cables and potential future expansions.Quizlet

In Wi-Fi networks, Quality of Service (QoS) is managed through the Wi-Fi Multimedia (WMM) specification, which categorizes traffic into four Access Categories (ACs):

AC_VO (Voice)

AC_VI (Video)

AC_BE (Best Effort)

AC_BK (Background)

Voice traffic is highly sensitive to latency and jitter, requiring the highest priority to ensure call quality. Therefore, voice frames should be mapped to theAC_VOcategory.

The CWDP-305 Official Study and Reference Guide emphasizes:

"Voice traffic should be assigned to the AC_VO category to ensure the highest priority and minimal latency."

For long-distance point-to-point wireless links, such as those spanning over 1000 yards, directional antennas are preferred due to their focused beamwidth and higher gain.Yagi antennas are a type of directional antenna known for their high gain and narrow beamwidth, making them suitable for such applications.While panel and patch antennas are also directional, Yagi antennas are specifically designed for long-range communications.

Dynamic Frequency Selection (DFS) channels are shared with radar systems, such as those used in airports.Enabling DFS in such environments can lead to interference with radar operations and cause APs to frequently change channels, disrupting WLAN stability.Therefore, DFS channels should not be enabled in airport environments.

The CWDP-305 Official Study and Reference Guide advises against the use of DFS channels in areas where radar systems operate to prevent potential interference and ensure network reliability.

When APs are deployed in the same physical pattern across floors without channel and physical spacing considerations, co-channel interference (CCI) between floors occurs. This is particularly problematic when APs on different floors are vertically aligned on the same channels.

From CWDP-305:

“In multi-floor deployments, avoid placing APs on the same vertical axis across floors using the same channel. This leads to CCI. Stagger AP locations and vary channels to reduce interference.”

— Reference: CWDP-305 Official Study Guide, Wireless Design Process Chapter

EAP-PEAP is the most suitable 802.1X-based authentication method for environments that do not have a public key infrastructure (PKI). It uses a server-side certificate but does not require client-side certificates, simplifying deployment while maintaining strong authentication.

From CWDP-305:

“EAP-PEAP allows secure authentication using usernames and passwords without requiring client certificates, making it ideal for organizations lacking PKI infrastructure.”

Other options:

EAP-TLS requires a PKI and client certificates (not suitable here).

PSK (pre-shared key) options don’t use 802.1X.

TKIP/RC4 is deprecated and insecure.

— Reference: CWDP-305 Official Study and Reference Guide, Chapter on Wireless Design Process

In North America, Wi-Fi devices operating in the 2.4 GHz band are typically restricted to channels 1 through 11. However, in Europe, channels 12 and 13 are also permitted. If a European AP is configured to operate on channel 13, a North American device may not recognize or connect to it, leading to low RSSI readings or inability to connect.

Passei Direto

How-To Geek

In this scenario, the AP in the room is likely operating on channel 13, which the traveler's device cannot utilize, resulting in low RSSI. Conversely, the lobby APs are operating on channels 1 through 11, which are compatible with the traveler's device, leading to normal RSSI readings.

Other options, such as the AP using ZigBee or Bluetooth, are unlikely, as these technologies are distinct from Wi-Fi and would not present as Wi-Fi SSIDs. The switchport speed, while affecting throughput, does not directly impact RSSI.