- Data frame
- Frame contains data intended for one of the
station
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- Poll frame (called the
CF poll frame in IEEE 802.11)
- contains a poll message for a
station
- The station receiving
the poll message
must transmit
one frame
- If the station
has no frame to
transmit, it must send a
null message
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- (Data + Poll) frame
- This is a combined message
containing a message
and a
poll
for the
same station
- The station will
receive (and process) the
message
- Then the station must send
a message
(because it was polled)
- If the station has no data to
transmit, it sends a
null message
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- End frame
- This frame will
terminate
the PCM mode
Effect:
- The Access Point
and the
nodes will
use
Distributed Coordinated Function (DCF)
as the operational mode
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