CWNP CWDP-305 Questions Answers

160 MHz channels consume a large portion of the available spectrum. Due to DFS and regulatory limitations, very few 160 MHz-wide channels are available in the 5 GHz band. This makes them impractical for most enterprise environments where avoiding interference and ensuring channel reuse are critical.

From CWDP-305:

“Due to the limited number of non-overlapping 160 MHz channels in the 5 GHz band—and DFS limitations—these channels are difficult to deploy in enterprise WLANs. This limits their usefulness in dense environments.”

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

Channels 116-124 in the 5 GHz band fall under the Dynamic Frequency Selection (DFS) range. These channels are shared with radar systems, such as those used by airports. When radar activity is detected, Access Points (APs) operating on DFS channels must vacate the channel, leading to potential disruptions in service. In environments near airports, it's advisable to avoid using DFS channels to prevent such interruptions, ensuring a stable and reliable wireless experience for voice devices.

When the WLAN controller and APs reside on different subnets, a router is required to facilitate communication between them. The router enables Layer 3 routing, allowing the APs to discover and communicate with the controller across subnet boundaries.