ieee 802.11协议标准技术指南

ieee 802.11协议标准技术指南

IEEE 802.11 Architecture
Architecture Components
An 802.11 LAN is based on a cellular architecture where the system is subdivided into cells, where each
cell (called Basic Service Set or BSS, in the 802.11 nomenclature) is controlled by a Base Station (called
Access Point, or in short AP).
Even though that a wireless LAN may be formed by a single cell, with a single Access Point, (and as will
be described later, it can also work without an Access Point), most installations will be formed by several
cells, where the Access Points are connected through some kind of backbone (called Distribution System
or DS), typically Ethernet, and in some cases wireless itself.
The whole interconnected Wireless LAN including the different cells, their respective Access Points and
the Distribution System, is seen to the upper layers of the OSI model, as a single 802 network, and is
called in the Standard as Extended Service Set (ESS).
The following picture shows a typical 802.11 LAN, with the components described previously: