The service set identifier (SSID) defines a service set or extended service set. Normally it is broadcast in the clear by stations in beacon packets to announce the presence of a network and seen by users as a wireless network name.
Unlike basic service set identifiers, SSIDs are usually customizable. These SSIDs can be zero to 32 octets (32 bytes) long, and are, for convenience, usually in a natural language, such as English. The 802.11 standards prior to the 2012 edition did not define any particular encoding or representation for SSIDs, which were expected to be treated and handled as an arbitrary sequence of 0–32 octets that are not limited to printable characters. IEEE Std 802.11-2012 defines a flag to express that the SSID is UTF-8-encoded and could contain any Unicode text. Wireless network stacks must still be prepared to handle arbitrary values in the SSID field.