Cisco Unified Wireless — What does “split-MAC” architecture mean? In Cisco's Unified Wireless Solution, explain the split-MAC architecture and choose the correct description that reflects how 802.11 processing is divided between lightweight access points (APs) and the wireless LAN controller (WLC).

Introduction / Context:
Enterprise Wi-Fi systems often centralize control to simplify configuration, roaming, and security. Cisco's “split-MAC” architecture underpins lightweight AP (LAP) deployments with a Wireless LAN Controller (WLC), dividing responsibilities for 802.11 tasks to optimize performance and manageability.

Given Data / Assumptions:

• Lightweight APs are joined to a WLC via CAPWAP tunnels.
• Management and control functions can be centralized.
• Latency-sensitive RF functions should remain near the air interface.

Concept / Approach:
In split-MAC, time-critical 802.11 operations (for example, beaconing, probe/association handling, RF measurements) are performed on the AP, while centralized tasks (authentication policy, roaming decisions, QoS enforcement, VLAN mapping) execute on the controller. Frames are encapsulated and transported to the WLC, which applies policy and forwards traffic. This yields simplified management, consistent policy, and faster roaming while keeping radio-timing tasks local to the AP.

Step-by-Step Solution:
Identify the architecture: lightweight AP + WLC with CAPWAP tunnels.Map time-critical MAC functions to AP; central policy/forwarding to WLC.Recognize that this is a split of MAC-layer responsibilities, not simply addressing.Select the option that states 802.11 processing is split between AP and controller.

Verification / Alternative check:
Controller configuration guides show that association, authentication state, and client policy are centrally tracked; AP radios still transmit beacons and respond quickly to probes, confirming the functional split.

Why Other Options Are Wrong:

• A/D: Descriptions of switching/bridging behavior; not about 802.11 function partitioning.
• C: Merely restates wired vs. wireless addressing; ignores the split of MAC duties.
• E: Oversimplified; controllers commonly process management/control information as well via CAPWAP control channel.

Common Pitfalls:
Assuming APs are “thin” to the point of doing almost nothing; in reality they still handle timing-critical RF work in split-MAC designs.

Final Answer:
The split-MAC architecture splits 802.11 protocol functions between the AP and the controller so both devices process portions of each frame exchange.