Interpretation of service class parameter in MAC service primitives in a STA

5.1.1.5 Interpretation of service class parameter in MAC service primitives in a STA

In QoS STAs, the value of the service class parameter in the MAC service primitive (see 5.2) may be a
noninteger value of QoSAck or QoSNoAck.
When an MSDU is received from the MAC_SAP and the recipient STA is a QoS STA with the service class
set to
— QoSAck, the MSDU is transmitted using a QoS data frame with the Ack Policy subfield in the QoS
Control field set to either Normal Ack (normal acknowledgement) or Block Ack.
— QoSNoAck, the MSDU is transmitted using a QoS data frame with the Ack Policy subfield in the
QoS Control field set to No Ack (no acknowledgement). If the sender STA is contained within an
AP and the frame has a group DA, then the MSDU is buffered for transmission and is also sent to
the DS.

When an MSDU is received from the MAC_SAP and the recipient STA is not a QoS STA, the MSDU is
transmitted using a non-QoS data frame.
When a QoS data frame is received from another STA, the service class parameter in the
MA-UNITDATA.indication primitive is set to
— QoSAck, if the frame is a QoS data frame with the Ack Policy subfield in the QoS Control field
equal to either Normal Ack or Block Ack.
— QoSNoAck, if the frame is a QoS data frame with the Ack Policy subfield in the QoS Control field
equal to No Ack. This service class is also used where the DA parameter is a group address.
When a non-QoS data frame is received from a STA, the service class parameter in the
MA-UNITDATA.indication primitive is set to
— QoSAck, if the frame is an individually addressed frame and is acknowledged by the STA.
— QoSNoAck, if the frame is a group addressed frame and is not acknowledged by the STA.
Note that the group addressed frames sent by a non-QoS STA are not acknowledged regardless of the value
of the service class parameter in the MA-UNITDATA.indication primitive.