frame control (TR/FDDI/802.11) (FC)
- In the token ring frame, the frame control field is a 1- byte long data field. The first two bits of the FC field are used to identify the type of data packet, whereby a distinction is made between three different types: the MAC frame, the LLC frame and an undefined type.
- In the FDDI frame, the frame control (FC) field is also one byte long and identifies the frame for the transmission of data, tokens and control information, or it is used for error recovery. The FC data field specifies the size of the address field and whether the data frame contains synchronous or asynchronous data.
- In 802.11WLANs, the frame control field is 2 bytes long and consists of several elements: protocol used. The 2 bit long Type field identifies the function of the frame and distinguishes between Control Frames, Data Frames and Management Frames. The 4 bit long data field Subtype specifies in connection with the Type field the functionality of the frame and distinguishes 25 different subtypes. The following two 1 bit data fields To Distribution System( DS) and From Distribution System are set if the frame is intended for distribution systems. More Fragments is set to 1 for all data and management packets if they are not the last fragment. Retry (1) is set to 1 for data and management packets that have already been transmitted. The 1 bit long data field Power Management indicates the power saving mode of a station. More Data indicates to a station in power saving mode that more data packets are present at the access point( AP). WEP (1) is for the WEP algorithm and Order (1) is for data packets transported according to the highest class of service.
- In the low bit rate Wireless PersonalArea Networks(WPAN) according to 802.15.4, Frame Control is a 2 byte data field in the MAC header. One bit of this frame is used to activate the security control, Security Control, a data field in the Auxiliary Security Header.