Data frame
From Free net encyclopedia
In telecommunications, a frame is a packet which has been encoded for transmission over a particular link.
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How framing works
This process involves, at a minimum, adding delimiters to distinguish the packet from dead air, address and control fields specific to the link, and checksums to detect errors.
- Sometimes the address, control, and checksum fields from the higher-level protocol are used directly.
Image:Packets-and-Frames illustration.png
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A multiplex interpretation of 'Frames'
Frame may also refer to the way a multiplexer divides the underlying communication channel so that it can be used simultaneously for more than one transmission. Notionally, each frame is a slot which could be filled by a transmitted packet. In these schemes, not all frames are necessarily in use at once.
- In the multiplex structure of pulse-code modulation (PCM) systems, a frame is a set of consecutive time slots in which the position of each digit can be identified by reference to a frame-alignment signal. (This signal does not necessarily occur in each frame.)
- In a time-division multiplexing (TDM) system, a frame is a repetitive group of signals resulting from a single sampling of all channels. The term in-frame is used to indicate that a time-division multiplexer is properly synchronized with the demultiplexer on the other end of the link, so that (barring in-flight data corruption) packets will be properly received.