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The very first two octets transmitted by a station are the Frame Control. The first three subfields within the frame control and the last field are always present in all types of 802.11 frames. These three subfields consist of two bits Protocol Version subfield, two bits Type subfield, and four bits Subtype subfield.
802.11 Beacon frame. A beacon frame is a type of management frame in IEEE 802.11 WLANs. It contains information about the network. Beacon frames are transmitted periodically; they serve to announce the presence of a wireless LAN and to provide a timing signal to synchronise communications with the devices using the network (the members of a service set).
Current 802.11 standard defines "frame" types for use in management and control of wireless links. IEEE 802.11w is the Protected Management Frames standard for the IEEE 802.11 family of standards. Task Group 'w' worked on improving the IEEE 802.11 Medium Access Control layer. [1]
Type: Two bits identifying the type of WLAN frame. Control, Data, and Management are various frame types defined in IEEE 802.11. Subtype: Four bits providing additional discrimination between frames. Type and Subtype are used together to identify the exact frame. ToDS and FromDS: Each is one bit in size. They indicate whether a data frame is ...
IEEE 802.11 RTS/CTS (request to send/clear to send) is the optional mechanism used by the 802.11 wireless networking protocol to reduce frame collisions introduced by the hidden node problem. Originally the protocol fixed the exposed node problem as well, but later RTS/CTS does not, but includes ACKs.
Traffic indication map (TIM) is a structure used in 802.11 wireless network management frames.. The traffic indication map information element is covered under section 7.3.2.6 of 802.11-1999 standard.
Every frame transmitted by an 802.11 device has a significant amount of overhead, including radio level headers, media access control (MAC) frame fields, inter-frame spacing, and acknowledgement of transmitted frames. At the highest data rates, this overhead can consume more bandwidth than the payload data frame. [1]
Block acknowledgement (BA) was initially defined in IEEE 802.11e as an optional scheme to improve the MAC efficiency. 802.11n amendment ratified in 2009 enhances this BA mechanism then made it as mandatory to support by all 802.11n-capable devices (formally known as HT - High Throughput devices).