what is the function of the Service Set Identifier (SSID)?

In the Company wireless LAN, what is the function of the Service Set Identifier (SSID)?

A.
The SSID must match on both the Company client and the Company access point
and provides MAC Address Authentication to authenticate the client to the access point.

B.
The SSID should be configured on the Company client site only and provides dataprivacy functions and authentication to the access point.

C.
The SSID must match on both the Company client and the Company access point
and provides encryption keys for authentication to the access point.

D.
The SSID must match on both the Company client and the Company access point.
The SSID is advertised in plain-text in the access point beacon messages.
None of the other alternatives apply

Explanation:
The SSID is the name of the wireless cell. It is used to logically separate Wireless LANs. It
must match exactly between the client and the access point. The SSID is advertised in plaintext in the access point beacon messages (Figure 8). Although beacon messages are

transparent to users, an eavesdropper can easily determine the SSID with the use of an
802.11 wireless LAN packetanalyzer, like Sniffer Pro. Some access-point vendors, including
Cisco, offer the option to disable SSID broadcasts in the beacon messages. The SSID can
still be determined by sniffing the probe response frames from an access point. The SSID is
not designed, nor intended for use, as a security mechanism. In addition, disabling SSID
broadcasts might have adverse effects on Wi-Fi interoperability for mixed-client
deployments. Therefore, Cisco does not recommend using the SSID as a mode of security.
A Comprehensive Review of 802.11 Wireless LAN Security and the Cisco
Wireless Security Suite
http://www.teksell.com/whitepapers/cisco_wireless.pdf