802.11 Protocol Architecture
beacon frames. These values are known as Received Signal Strength
Indicators (RSSIs).
Data Protection
Optional encryption alters the payload bits of each data frame to
prevent hackers from understanding the contents of frames in-transit
between stations and access points.
Power management
Stations include transceivers that consume significant power that can
drain batteries relatively quickly. The optional 802.11 power-save
function allows a station to periodically enter and exit a doze state,
which uses much less power and increases battery life.
Fragmentation
Sometimes, such as in the presence of RF interference, it is beneficial
to break larger frames into smaller frames before transmission across a
wireless link. The 802.11 standard defines fragmentation as an
optional function, and it can be initiated on either the client station or
the access point or both. Fragmentation is unique to each wireless link.
Request-to-Send / Clear-to-Send (RTS/CTS)
Hidden nodes may exist on the network that can significantly increase
collisions, which reduces performance. The 802.11 RTS/CTS
mechanism can optionally be used by stations and access points to
announce the intended transmission of unicast data and management
frames over a certain threshold size in order to limit retransmission
time when hidden nodes are present. RTS/CTS may also used as an
optional protection mechanism by 802.11g stations to announce the
intended transmission of ERP-OFDM frames in an 802.11b/g mixed
mode environment.
Management
The 802.11 standard defines a Management Information Base (MIB)
that contains many parameters that impact the operation of the wireless
