Hierarchy of wireless nodes
The hierarchy of wireless nodes is displayed as follows:
• ESSID (Extended Service Set Identifier): the name of a logical group of access points
• BSSID (Basic Service Set Identifier): a single access point
• STA (Station): a client associated to the particular access point
Each individual station (STA) is arranged under the BSSID of the access point (or equivalent) to which it most recently sent a packet.
Stations which have never sent a packet cannot be assigned to an actual BSSID. Until they send a packet to an access point or to a member of an ad hoc group, these nodes are displayed under BSSID Unknown. Three classes of addresses show up in the ESSID Unknown/BSSID Unknown category:
• Broadcast and multicast addresses, tagged as Admin in the Type column.
• Stations which have sent a Probe Request to a particular ESSID, but which have not associated with any known BSSID.
• Nodes which cannot be assigned to any BSSID or ESSID because of the hidden node problem (you can detect only one participant in a conversation, because the other is beyond your range).