ITM 301 Chapter 4: Chapter 4 Medium Access Control Sublayer PART 2
Document Summary
The 802. 11 standard defines three different classes of frames in the air: data, control, and management. Each of these has a header with a variety of fields used within the mac sublayer. Data frame: first comes the frame control field which is made up of 11 subfields: frame control field(bits): protocol version which is 00 to allow future versions of 802. 11 to operate. Type (data, control, or management) and subtype fields (rts or cts). The to ds and from ds bits are set to indicate whether the frame is going to or coming from the network connected to the aps = distribution system. More fragments bit means more fragments will follow. The retry marks a retransmission of a frame sent earlier. Power management indicates that the sender is going into power save made. More-data bit indicates that the sender has additional frames for the receiver. Protected demonstrates that the frame body has been encrypted for security.