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Zorluk: ZorCisco Wireless Architectures and AP Modes

An enterprise network deployment includes Lightweight Access Points (LAPs) managed by a centralized Wireless LAN Controller (WLC). During a scheduled link maintenance event, WAN connectivity between a branch office LAP and the centralized WLC is temporarily lost. The branch LAP is operating in FlexConnect mode with local switching and local authentication enabled for the employee SSID. Meanwhile, a campus LAP connected to the main network operates in default Local mode. Upon loss of the CAPWAP connection, clients connected to the FlexConnect AP continue transmitting data to local resources, whereas clients connected to the Local mode AP immediately lose network access. Which architectural requirement causes the Local mode AP to cease forwarding client data traffic when controller connectivity is lost?

  1. Local mode APs require an active CAPWAP data tunnel to encapsulate all client 802.11 payload into 802.3 frames at the WLC, preventing autonomous local Layer 2 frame switching at the AP level.Cevap
  2. B
    Local mode APs automatically transition into Rogue Detector mode upon losing the CAPWAP control tunnel, which disables radio interfaces to monitor the wired switch MAC address table.
  3. C
    Local mode APs switch client data traffic locally but rely on the WLC to maintain dynamic ARP table entries, causing client IP-to-MAC resolution to fail immediately when controller keepalives time out.
  4. D
    Local mode APs delegate 802.11 management processing to the AP while reserving 802.11 data frame encapsulation exclusively for the local access switch trunk interface.

Cevap

Local mode APs encapsulate all client traffic within CAPWAP data tunnels that terminate at the Wireless LAN Controller (WLC). When controller connectivity is lost, the CAPWAP data tunnel drops, making local switching impossible for Local mode APs.
In Cisco centralized wireless architectures, access points in default Local mode enforce central switching. All wireless client payload is encapsulated in CAPWAP data packets and forwarded over the network to terminate directly at the Wireless LAN Controller. If controller reachability is lost, the CAPWAP data tunnel drops, and because Local mode APs are not provisioned with local VLAN-to-SSID mappings, client traffic cannot be forwarded locally.

Adım Adım Çözüm

1
Analyze the functional difference between Cisco LAP operational modes.
Local mode APs use Centralized Switching, sending all control and data traffic through CAPWAP tunnels to the WLC. FlexConnect APs support Local Switching, allowing traffic to bypass the CAPWAP tunnel at the branch switch interface.
Understanding data plane encapsulation is essential to evaluating behavior during controller connectivity outages.
2
Evaluate the impact of a lost CAPWAP tunnel on Local mode AP operations.
Without an reachable WLC to decapsulate CAPWAP packets and bridge client traffic onto local VLANs, a Local mode AP cannot locally switch 802.11 frames to 802.3 Ethernet frames.
Local mode APs lack the local VLAN mapping and switching configuration resident on FlexConnect APs.
3
Identify the option correctly describing CAPWAP data tunnel dependence.
The option specifying that Local mode APs require an active CAPWAP data tunnel for central frame processing and encapsulation is correct.
This directly explains why loss of WLC communication prevents Local mode APs from sustaining client data transmission.

Anahtar Kavram

Cisco Split-MAC Architecture and AP Modes (Local vs. FlexConnect)
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Konular

Cisco Wireless Architectures and AP Modes

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