CWDP Outdoor and Mesh Networking Flashcards

What is the primary advantage of using a mesh WLAN architecture over a traditional wired infrastructure deployment in outdoor environments?

Answer: Elimination of cabling requirements by using wireless backhaul between nodes

Mesh networks use wireless backhaul between nodes, avoiding the need to trench cables to every AP location.

In an outdoor point-to-point wireless bridge, what is the first Fresnel zone and why must it be kept clear?

Answer: An elliptical region around the direct path where reflections constructively interfere; obstruction causes significant signal loss

The first Fresnel zone must be at least 60% clear of obstructions to avoid destructive interference that degrades link performance.

What path loss model is most commonly used for outdoor WLAN link budget calculations in open terrain?

Answer: Free-Space Path Loss (Friis) model

The Friis free-space path loss model is used for outdoor line-of-sight links, calculating loss based on distance and frequency.

Which regulatory domain restriction must a CWDP consider when deploying outdoor 5 GHz point-to-point bridges in the US?

Answer: UNII-2 and UNII-2 Extended channels require DFS radar detection and avoidance

UNII-2 and UNII-2e channels in the 5 GHz band require Dynamic Frequency Selection (DFS) to detect and avoid radar interference.

In a mesh network, what is 'backhaul efficiency' and how does the number of hops affect it?

Answer: Each additional mesh hop typically halves available client throughput due to half-duplex relay overhead

Each wireless mesh hop roughly halves throughput because the relay node must receive and retransmit on the same channel.

What design technique allows a mesh AP to avoid throughput halving by separating backhaul and access traffic?

Answer: Deploying dual-radio or tri-radio mesh nodes with dedicated backhaul radios

Dedicated backhaul radios (on a separate channel or band) allow simultaneous backhaul and client access without sharing the medium.