SSID: service set identifier.
ESS: extended service set, a group of all SATs in the same logical management domain. An ESS may contain multiple BSSs.
BSS: basic service set, an area covered by an AP. Each BSS is identified by a BSSID. The simplest WLAN contains only one BSS, and all STAs are in the BSS. To enable the STAs to communicate, disable STA isolation.