Appendix B Wireless LANs
AX/DX/EX/PX Series User’s Guide
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Figure 291   Basic Service Set
ESS
An Extended Service Set (ESS) consists of a series of overlapping BSSs, each containing an access point, 
with each access point connected together by a wired network. This wired connection between APs is 
called a Distribution System (DS).
This type of wireless LAN topology is called an Infrastructure WLAN. The Access Points not only provide 
communication with the wired network but also mediate wireless network traffic in the immediate 
neighborhood. 
An ESSID (ESS IDentification) uniquely identifies each ESS. All access points and their associated WiFi 
clients within the same ESS must have the same ESSID in order to communicate.