Question 1
On a branch office deployment, it has been noted that if the FlexConnect AP is in standalone mode and loses connection to the WLC, all clients are disconnected, and the SSID is no longer advertised. Considering that FlexConnect local switching is enabled, which setting is causing this behavior?
The AI suggests that the correct answer is A.
The suggested answer aligns with the provided rationale which highlights the behavior of FlexConnect APs in standalone mode when ISE NAC (RADIUS NAC) is enabled and the connection to the WLC is lost. This scenario leads to client disconnections and SSID suppression because the AP cannot authenticate clients independently.
Here's a detailed breakdown of why the other options are less likely:
- B. 802.11r Fast Transition: This feature primarily deals with improving roaming performance and wouldn't directly cause a complete disconnection and SSID suppression upon WLC connectivity loss.
- C. Client Exclusion: Client exclusion is a feature used to temporarily block misbehaving clients, but it wouldn't typically lead to a complete SSID shutdown when the WLC connection is lost.
- D. FlexConnect Local Auth is disabled: While disabling local authentication would impact new client connections *after* the WLC link is lost, it would not immediately disconnect already authenticated clients. The key issue here is the reliance on a central authority (ISE via the WLC) for authentication, which is lost when the AP goes standalone.
The core issue is the dependency on the WLC for authentication and authorization via ISE NAC. When the FlexConnect AP loses its connection to the WLC in standalone mode, it can no longer validate client credentials against the ISE server. Without successful authentication, the AP will disconnect clients and stop advertising the SSID.
For more information regarding FlexConnect deployments and considerations, refer to the Cisco documentation on FlexConnect. Cisco's documentation explains clearly that RADIUS server is required for authentication. If a FlexConnect AP loses connectivity to the WLC, the AP is unable to reach the RADIUS server and therefore unable to authenticate clients.
It is important to note that, when the FlexConnect AP is in standalone mode and loses connection to the WLC, if the RADIUS is unavailable, all clients are disconnected, and the SSID is no longer advertised.
Citations:
- Cisco FlexConnect Deployment Guide, https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/flexconnect.html
