What is an SSID?

SSID stands for Service Set Identifier, which is a 32-character sequence that uniquely identifies a wireless LAN (WLAN). In other words, the SSID is the name of the wireless network.

The significance of the SSID is not obvious until you examine the way it functions:

• It uniquely identifies a wireless network, which is of vital importance in a wireless environment. A wireless computer or other device sitting between a number of wireless access points (WAPs) can "see" and broadcast to all of them. The SSID is what the computer or device uses to identify the correct WAP.
  
  
• It acts as a "passkey" to a specific network; a WAP for a given wireless network won't accept network traffic from a wireless computer or other device unless it has the network's SSID in its packet headers.

In sum, the SSID is both what you use to identify a wireless network and what the wireless adapter and WAPs use to communicate with each other.