Term:SSID [Service Set IDentifier]
SSID is an acronym for Service Set IDentifier. More commonly, it’s the “network name” that’s assigned to a Wi-Fi wireless access point.
The SSID is typically broadcast by a Wi-Fi access point to announce its presence and to allow computer users to identify the access point and network that they might then connect to. Broadcasting the SSID is actually optional, and can be used to keep a network from appearing in “nearby networks” types of lists.
In IEEE 802.11 wireless local area networking standards (including Wi-Fi), a service set is a group of wireless network devices which share a service set identifier (SSID)—typically the natural language label that users see as a network name. (For example, all of the devices that together form and use a Wi‑Fi network called Foo are a service set.) A service set forms a logical network of nodes operating with shared link-layer networking parameters; they form one logical network segment.
A service set is either a basic service set (BSS) or an extended service set (ESS).
A basic service set is a subgroup, within a service set, of devices that share physical-layer medium access characteristics (e.g. radio frequency, modulation scheme, security settings) such that they are wirelessly networked. The basic service set is defined by a basic service set identifier (BSSID) shared by all devices within it. The BSSID is a 48-bit label that conform to MAC-48 conventions. While a device may have multiple BSSIDs, usually each BSSID is associated with at most one basic service set at a time.
A basic service set should not be confused with the coverage area of an access point, known as the basic service area (BSA).