Question 128 of 240 from exam 400-351: CCIE Wireless Written Exam

Question 128 of 240 from exam 400-351: CCIE Wireless Written Exam


What does disabling broadcast SSID in the WLAN configuration do?



A. B. C. D. E.


When a client device wants to connect to a wireless network, it needs to first discover the available wireless networks. This process is done through the exchange of wireless management frames, specifically beacon frames. Beacon frames are broadcast frames that are sent periodically by wireless access points to advertise their presence and announce their configuration parameters, including the SSID (Service Set Identifier) of the wireless network.

By disabling the broadcast of the SSID in the WLAN configuration, the wireless access point will still send beacon frames, but the SSID name field will be left empty, effectively hiding the network from casual users who are scanning for available networks. Clients that have previously connected to the network will still be able to connect by manually specifying the SSID.

The correct answer to the question is option C, which states that disabling broadcast SSID allows beacons to be sent but leaves the SSID name field empty. Option A is incorrect because disabling broadcast SSID does not change the frame type from broadcast to unicast. Option B is incorrect because preventing beacons from being sent would effectively make the network invisible to all clients. Option D is incorrect because forbidding all broadcasts for that SSID would also prevent necessary control and management frames from being sent, which could cause connectivity issues. Option E is incorrect because making the SSID respond only to blank probes would also effectively hide the network from all clients.